This work was supported by grants from the National Institutes of Health, National Institute of General Medical Science (R01GM063075) and the National Center of Complementary and Alternative Medicine (R01AT05076).

1. Establishment of Animal Model of Sepsis
<ol>
	<li>Mice are anesthetized with ketamine (75 mg/kg, intramuscular, i.m.) and xylazine (10 mg/kg, i.m.), and placed in supine position.</li>
	<li>Fix the feet of the mouse with tape to ensure a stable position.</li>
	<li>Clean the abdomen with 3 alternating scrubs of betadine or other skin disinfectant and alcohol. Then, make a 15 mm midline incision to expose the cecum.</li>
	<li>Ligate the cecum with a 4-0 silk suture at approximately 5.0 mm from the cecal tip, and then puncture the ligated cecal stump once with a 22-gauge needle to allow extrusion of stool.</li>
	<li>The cecum is immediately replaced back to its normal intra-abdominal position.</li>
	<li>Close the incision site in two layers, by first closing the musculature of the abdomen with absorbable sutures, and then closing the skin with wound clips or nonabsorbable sutures. </li>
	<li>Resuscitate mouse with 0.5 ml normal saline solution and a single dose of imipenem (0.5 mg/mouse, subcutaneously) immediately after the completion of the surgical procedure.</li>
	<li>Return the mouse back to a clean cage with free access to food and water.</li>
	<li>At various time points post CLP, herbal extract or component is administered intraperitoneally.</li>
	<li>Animal survival is monitored for more than two weeks. Moribund animals exhibiting difficulties to stand, agonal breathing, severe muscular atrophy and uncontrolled bleeding should be euthanized by overdose carbon dioxide inhalation. </li>
	<li>It is important to note that circulating cytokine levels are important parameters in these studies. Various analgesics have been shown to affect cytokine release and activities, and therefore have been intentionally avoided in postoperative care. </li>
</ol>
2. Preparation of Herbal Extract
<ol>
	<li>Extract herbs in hot water (85 &deg;C) for 1-4 hr (1 hr for leaves, and 4 hr for roots).</li>
	<li>Centrifuge the water-soluble fraction (3300 g, 20 min, 4 &deg;C) to remove insoluble particles.</li>
	<li>Filtrate the supernatant fraction through a 0.2 &mu;m filter.</li>
	<li>The clear water-soluble filtrate fraction is then fractionated by ultrafiltration using Centriprep YM-10 Centrifugal Filter (Catalog no. 4305, Millipore).</li>
	<li>The resulted low (&lt;10 kDa) and high (&gt; 10 kDa) molecular weight fractions (MWF) are screened for HMGB1-inhibiting activities using macrophage cultures.</li>
	<li>Intraperitoneal administration of HMGB1-inhibiting herbal extract or components at 24 hr post CLP to evaluate their therapeutic efficacy.</li>
</ol>
3. Peritoneal Macrophage Isolation
<ol>
	<li>Thioglycollate broth (4%, 2.0 ml) is administered intraperitoneally into normal mice.</li>
	<li>Primary peritoneal macrophages are harvested at 3 days as previously described10.</li>
	<li>Macrophages are pre-cultured in DMEM medium (Gibco BRL, Grand Island, NY) supplemented with 10% fetal bovine serum (FBS), 2 mmol/L glutamine, and 1% penicillin.</li>
	<li>Adherent macrophages are gently washed with, and cultured in, serum-free OPTI-MEM I medium two hours before stimulation with bacterial endotoxin (lipopolysaccharide, LPS, E. coli 0111:B4, Sigma-Aldrich).</li>
	<li>At 16 hours after LPS stimulation, levels of HMGB1 in the culture medium are determined by Western blotting analysis11.</li>
	<li>The relative band intensity was quantified by using the NIH image 1.59 software to determine HMGB1 levels with reference to standard curves generated with purified HMGB1.</li>
</ol>
4. Representative Results
1. CLP induces systemic and local inflammation.
Within a few hours of CLP surgery, animals exhibit clinical signs of sepsis that include piloerection, lethargy, huddling, and decrease in food and water intake. Animals developing a severe peritonitis with consecutive systemic infection normally die within 48 - 96 hr. However, even age-, sex-, and genetic background-matched animals can respond to CLP surgery in a distinguishable manner in the course of experimental sepsis. For instance, at 48 hr post CLP, while some animals may have approached the moribund state (as defined in Figure 1), others may remain at a non-moribund state.
Comprehensive surveys of circulating cytokines revealed dramatic differences in levels of several cytokines (e.g., IL-6, KC, MIP-2, and sTNFR1) between mice in the moribund and non-moribund states (Figure 1)12. Notably, these inflammatory mediators have been classified as surrogate markers of sepsis because their circulating levels are reliable predictors of lethal outcome in experimental12-14 or clinical sepsis15. In addition, CLP also induced local release of various pro- and anti-inflammatory cytokines and chemokines. For instance, at 48 hr post CLP, significant amounts of cytokines (e.g., IL-6) and chemokines (KC and MIP-2) can still be measured not only systemically in the blood, but also locally in the peritoneal lavage fluid (Figure 2).
2. Screening for HMGB1-inhibiting herbal extract or components.
Using macrophage cultures, we were able to evaluate the capacities of various herbal extract or components in inhibiting endotoxin-induced HMGB1 release (Figure 3). In light of their capacity in inhibiting HMGB1 release, we further explored their efficacy in animal models sepsis. Given the late and prolonged kinetics of HMGB1 accumulation in experimental sepsis8, the first dose of HMGB1 inhibitors was given 24 hr after the onset of sepsis - a time point when mice developed clear signs of sepsis including lethargy, diarrhea, and piloerection. As shown in Figure 4, delayed and repeated administration of a major green tea component, epigallocatechin-3- gallate (EGCG), beginning at 24 h after onset of sepsis, significantly rescued mice from lethal sepsis12. Even when given orally, EGCG still rescued mice from lethal sepsis, significantly increasing animal survival rates from 16% to 44%16. It would be important to determine whether combinational therapies with several herbal components could achieve a significant better protection in animal models of sepsis. Taken together, these experimental data validated our approach to screen novel therapeutic agents using an animal model of CLP-induced sepsis.
5. Representative Results
<img alt="Figure 1" src="/files/ftp_upload/3926/3926fig1.jpg" /> 
Figure 1. Circulating levels of surrogate markers are dramatically higher in septic animals approaching moribund state. Balb/C mice were subjected to sepsis by CLP and monitored for the development of signs of sickness. At a late stage of sepsis (52 hr post CLP), blood was collected from 3 normal mice (-CLP), 3 septic mice approaching the moribund state, and 3 septic mice in the non-moribund state. Serum was pooled from each group, and assayed for the cytokine profile by antibody arrays. Note the dramatic difference in the relative levels of several surrogate markers between different groups. Adapted from doi:10.1371/journal.pone.0001153.g006 with granted permission from the publisher.
<img alt="Figure 2" src="/files/ftp_upload/3926/3926fig2.jpg" /> 
Figure 2. Detection of local and systemic cytokines and chemokines at 48 hr post CLP. Balb/C mice were subjected to sepsis by CLP, and blood or peritoneal fluid were harvested at 48 h post CLP. Relative levels of several cytokines and chemokines in pooled serum or peritoneal lavage fluid were measured by cytokine antibody arrays, and expressed as arbitrary units (AU). As controls, blood and peritoneal fluid samples were obtained from normal healthy animals (-CLP) without laparotomy.
<img alt="Figure 3" src="/files/ftp_upload/3926/3926fig3.jpg" /> 
Figure 3. Herbal component dose-dependently inhibited endotoxin-induced HMGB1 release in primary macrophage cultures. Primary murine peritoneal macrophages were stimulated with LPS in the absence, or presence of herbal component (e.g., EGCG, 15 &mu;M). At 16 hours after LPS stimulation, levels of HMGB1 in the culture medium were determined by Western blotting analysis. Adapted from doi:10.1371/journal.pone.0001153.g006 with granted permission from the publisher.
<img alt="Figure 4" src="/files/ftp_upload/3926/3926fig4.jpg" /> 
Figure 4. Herbal component rescued mice from lethal sepsis. Balb/C mice were subjected to lethal sepsis by CLP, and herbal component (EGCG) was intraperitoneally administered at +24, +48, +72 hours post the onset of sepsis. Animal survival was monitored for up to two weeks. The Kaplan-Meier method was used to compare the differences in mortality rates between groups. *, p &lt; 0.05 versus saline. Adapted from doi:10.1371/journal.pone.0001153.g006 with granted permission from the publisher.

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A.E.S. and H.W. are co-inventors of patent applications related to HMGB1 inhibitors (tanshinones) as potential therapeutic agents for sepsis.

In the laboratory, several animal models of sepsis have been employed to understand the pathogenesis of sepsis in order to develop potential novel therapies. Their clinical relevance remains a subject of debate before the successful translation of animal studies into clinical applications for sepsis. Although neutralizing antibodies against early cytokines (e.g., TNF) were protective in animal models of bacteremia/endotoxemia17,18, they actually worsen survival in animal model of sepsis19. Similarly...

<table border="1">
 <tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Company</td>
 <td>Catalogue number</td>
 </tr>
 <tr>
 <td>Betadine </td>
 <td>Purdue Products L.P.</td>
 <td>25655-41-8</td>
 </tr>
 <tr>
 <td>imipenem</td>
 <td>Merck &amp; Co., Inc.</td>
 <td>9882821</td>
 </tr>
 <tr>
 <td>Ketamine HCl</td>
 <td>Hospira Inc.</td>
 <td>RL-0065</td>
 </tr>
 <tr>
 <td>Xylazine</td>
 <td>Lloyd Laboratories</td>
 <td>4821</td>
 </tr>
 <tr>
 <td>Autoclip </td>
 <td>Becton Dickinson</td>
 <td>427631</td>
 </tr>
 <tr>
 <td>4-0 silk suture</td>
 <td>Roboz</td>
 <td>SUT-15-2</td>
 </tr>
 <tr>
 <td>Surflo I.V. Catheter</td>
 <td>Terumo</td>
 <td>SR*OX2419CA</td>
 </tr>
 <tr>
 <td>RayBio mouse cytokine antibody array</td>
 <td>RayBiotech, Inc.</td>
 <td>AAM-CYT-3</td>
 </tr>
 <tr>
 <td>Thioglycollate </td>
 <td>Becton Dickinson</td>
 <td>211716</td>
 </tr>
 </tbody>
</table>

use of animal model of sepsis to evaluate novel herbal therapies

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection. It has been routinely simulated in animals by several techniques, including infusion of exogenous bacterial toxin (endotoxemia) or bacteria (bacteremia), as well as surgical perforation of the cecum by cecal ligation and puncture (CLP)1-3. CLP allows bacteria spillage and fecal contamination of the peritoneal cavity, mimicking the human clinical disease of perforated appendicitis or diverticulitis. The severity of sepsis, as reflected by the eventual mortality rates, can be controlled surgically by varying the size of the needle used for cecal puncture2. In animals, CLP induces similar, biphasic hemodynamic cardiovascular, metabolic, and immunological responses as observed during the clinical course of human sepsis3. Thus, the CLP model is considered as one of the most clinically relevant models for experimental sepsis1-3.
Various animal models have been used to elucidate the intricate mechanisms underlying the pathogenesis of experimental sepsis. The lethal consequence of sepsis is attributable partly to an excessive accumulation of early cytokines (such as TNF, IL-1 and IFN-&gamma;)4-6 and late proinflammatory mediators (e.g., HMGB1)7. Compared with early proinflammatory cytokines, late-acting mediators have a wider therapeutic window for clinical applications. For instance, delayed administration of HMGB1-neutralizing antibodies beginning 24 hours after CLP, still rescued mice from lethality8,9, establishing HMGB1 as a late mediator of lethal sepsis. The discovery of HMGB1 as a late-acting mediator has initiated a new field of investigation for the development of sepsis therapies using Traditional Chinese Herbal Medicine. In this paper, we describe a procedure of CLP-induced sepsis, and its usage in screening herbal medicine for HMGB1-targeting therapies.

Watch this Scientific Journal Video about Use of Animal Model of Sepsis to Evaluate Novel Herbal Therapies at JoVE.com

Use of Animal Model of Sepsis to Evaluate Novel Herbal Therapies

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection, and can be simulated by a surgical technique termed cecal ligation and puncture (CLP). Here we describe a method to use CLP-induced animal model to screen medicinal herbs for therapeutic agents.

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection. It has been routinely simulated in animals by several ...

use-of-animal-model-of-sepsis-to-evaluate-novel-herbal-therapies

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Medicine

19.3K Views.  North Shore – LIJ Health System. Sepsi si riferisce ad una sindrome da risposta infiammatoria sistemica risultante da una infezione microbica, e può essere simulato da una tecnica chirurgica denominata legatura cecale e puntura (CLP). Qui si descrive un metodo per utilizzare CLP-indotta modello animale per lo screening erbe medicinali per gli agenti terapeutici.

Video: Use of Animal Model of Sepsis to Evaluate Novel Herbal Therapies

The CYP2D6 Animal Model: How to Induce Autoimmune Hepatitis in Mice

Autoimmune hepatitis is a rare but life threatening autoimmune disease of the liver of unknown etiology1,2. In the past many attempts have been made to generate an animal model that reflects the characteristics of the human disease 3-5. However, in various models the induction of disease was rather complex and often hepatitis was only transient3-5. Therefore, we have developed a straightforward mouse model that uses the major human autoantigen in type 2 autoimmune hepatitis (AIH-2), namely hCYP2D6, as a trigger6. Type 1 liver-kidney microsomal antibodies (LKM-1) antibodies recognizing hCYP2D6 are the hallmark of AIH-27,8. Delivery of hCYP2D6 into wildtype FVB or C57BL/6 mice was by an Adenovirus construct (Ad-2D6) that ensures a direct delivery of the triggering antigen to the liver. Thus, the ensuing local inflammation generates a fertile field9 for the subsequent development of autoimmunity. A combination of intravenous and intraperitoneal injection of Ad-2D6 is the most effective route to induce a long-lasting autoimmune damage to the liver (section 1). Here we provide a detailed protocol on how autoimmune liver disease is induced in the CYP2D6 model and how the different aspects of liver damage can be assessed. First, the serum levels of markers indicating hepatocyte destruction, such as aminotransferases, as well as the titers of hCYP2D6 antibodies are determined by sampling blood retroorbitaly (section 2). Second, the hCYP2D6-specific T cell response is characterized by collecting lymphocytes from the spleen and the liver. In order to obtain pure liver lymphocytes, the livers are perfused by PBS via the portal vein (section 3), digested in collagen and purified over a Percoll gradient (section 4). The frequency of hCYP2D6-specific T cells is analyzed by stimulation with hCYP2D6 peptides and identification of IFN&gamma;-producing cells by flow cytometry (section 5). Third, cellular infiltration and fibrosis is determined by immunohistochemistry of liver sections (section 6). Such analysis regimen has to be conducted at several times after initiation of the disease in order to prove the chronic nature of the model. The magnitude of the immune response characterized by the frequency and activity of hCYP2D6-specific T and/or B cells and the degree of the liver damage and fibrosis have to be assessed for a subsequent evaluation of possible treatments to prevent, delay or abrogate the autodestructive process of the liver.

Infection of mice with an Adenovirus expressing the major human autoantigen cytochrome P450 2D6 (hCYP2D6) recognized by sera of patients suffering from type 2 autoimmune hepatitis results in a persistent form of autoimmune-mediated liver disease characterized by extensive hepatitis, fibrosis and generation of a CYP2D6-specific immune response.

Autoimmune hepatitis is a rare but life threatening autoimmune disease of the liver of unknown etiology1,2. In the past many attempts have been made to ...

A Mouse Tumor Model of Surgical Stress to Explore the Mechanisms of Postoperative Immunosuppression and Evaluate Novel Perioperative Immunotherapies

Surgical resection is an essential treatment for most cancer patients, but surgery induces dysfunction in the immune system and this has been linked to the development of metastatic disease in animal models and in cancer patients. Preclinical work from our group and others has demonstrated a profound suppression of innate immune function, specifically NK cells in the postoperative period and this plays a major role in the enhanced development of metastases following surgery. Relatively few animal studies and clinical trials have focused on characterizing and reversing the detrimental effects of cancer surgery. Using a rigorous animal model of spontaneously metastasizing tumors and surgical stress, the enhancement of cancer surgery on the development of lung metastases was demonstrated. In this model, 4T1 breast cancer cells are implanted in the mouse mammary fat pad. At day 14 post tumor implantation, a complete resection of the primary mammary tumor is performed in all animals. A subset of animals receives additional surgical stress in the form of an abdominal nephrectomy. At day 28, lung tumor nodules are quantified. When immunotherapy was given immediately preoperatively, a profound activation of immune cells which prevented the development of metastases following surgery was detected. While the 4T1 breast tumor surgery model allows for the simulation of the effects of abdominal surgical stress on tumor metastases, its applicability to other tumor types needs to be tested. The current challenge is to identify safe and promising immunotherapies in preclinical mouse models and to translate them into viable perioperative therapies to be given to cancer surgery patients to prevent the recurrence of metastatic disease.

A mouse tumor model of surgical stress is used to explore how postoperative immune suppression promotes metastatic disease and to evaluate immunostimulatory perioperative therapies.

Surgical resection is an essential treatment for most cancer patients, but surgery induces dysfunction in the immune system and this has been linked to ...

Bioluminescence Imaging of an Immunocompetent Animal Model for Glioblastoma

In contrast to commonly reported human glioma xenograft animal models, GL261 murine glioma xenografts recapitulate nearly all relevant clinical and histopathologic features of the human disease. When GL261 cells are implanted intracranially in syngeneic C57BL/6 mice, the model has the added advantage of maintaining an intact immune microenvironment. Stable expression of luciferase in GL261 cells allows non-invasive cost effective bioluminescence monitoring of intracranial tumor growth. We have recently demonstrated that luciferase expression in GL261 cells does not affect the tumor growth properties, tumor cell immunomodulatory cytokine expression, infiltration of immune cells into the tumor, or overall survival of animals bearing the intracranial tumor. Therefore, it appears that the GL261 luciferase glioma model can be useful in the study of novel chemotherapeutic and immunotherapeutic modalities. Here we report the technique for generating stable luciferase expression in GL261 cells and how to study the in vitro and in vivo growth of the tumor cells by bioluminescence imaging.

GL261 glioma cells provide a useful immunocompetent animal model of glioblastoma. The goals of this protocol are to demonstrate proper techniques for monitoring intracranial tumor growth using in vivo bioluminescence imaging, and to verify the utility of luciferase-modified GL261 cells for studying tumor immunology and immunotherapeutic approaches for treating glioblastoma.

In contrast to commonly reported human glioma xenograft animal models, GL261 murine glioma xenografts recapitulate nearly all relevant clinical and ...

A Small Animal Model of Ex Vivo Normothermic Liver Perfusion

There is a significant shortage of liver allografts available for transplantation, and in response the donor criteria have been expanded. As a result, normothermic ex vivo liver perfusion (NEVLP) has been introduced as a method to evaluate and modify organ function. NEVLP has many advantages in comparison to hypothermic and subnormothermic perfusion including reduced preservation injury, restoration of normal organ function under physiologic conditions, assessment of organ performance, and as a platform for organ repair, remodeling, and modification. Both murine and porcine NEVLP models have been described. We demonstrate a rat model of NEVLP and use this model to show one of its important applications &#8212; the use of a therapeutic molecule added to liver perfusate. Catalase is an endogenous reactive oxygen species (ROS) scavenger and has been demonstrated to decrease ischemia-reperfusion in the eye, brain, and lung. Pegylation has been shown to target catalase to the endothelium. Here, we added pegylated-catalase (PEG-CAT) to the base perfusate and demonstrated its ability to mitigate liver preservation injury. An advantage of our rodent NEVLP model is that it is inexpensive in comparison to larger animal models. A limitation of this study is that it does not currently include post-perfusion liver transplantation. Therefore, prediction of the function of the organ post-transplantation cannot be made with certainty. However, the rat liver transplant model is well established and certainly could be used in conjunction with this model. In conclusion, we have demonstrated an inexpensive, simple, easily replicable NEVLP model using rats. Applications of this model can include testing novel perfusates and perfusate additives, testing software designed for organ evaluation, and experiments designed to repair organs.

A Small Animal Model of Ex Vivo Normothermic Liver Perfusion

There is a significant liver donor shortage, and criteria for liver donors have been expanded. Normothermic ex vivo liver perfusion (NEVLP) has been developed to evaluate and modify organ function. This study demonstrates a rat model of NEVLP and tests the ability of pegylated-catalase, to mitigate liver preservation injury.

There is a significant shortage of liver allografts available for transplantation, and in response the donor criteria have been expanded. As a result, ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

Novel Methods for Intranasal Administration Under Inhalation Anesthesia to Evaluate Nose-to-Brain Drug Delivery

Intranasal administration has been reported to be a potential pathway for nose-to-brain delivery of therapeutic agents that circumvents the blood-brain barrier. However, there have been few reports regarding not only the quantitative analysis but also optimal administration conditions and dosing regimens for investigations of nose-to-brain delivery. The limited progress in research on nose-to-brain pathway mechanisms using rodents represents a significant impediment in terms of designing nose-to-brain delivery systems for candidate drugs.
To gain some headway in this regard, we developed and evaluated two novel methods of stable intranasal administration under inhalation anesthesia for experimental animals. We also describe a method for the evaluation of drug distribution levels in the brain via the nose-to-brain pathway using radio-labeled [14C]-inulin (molecular weight: 5,000) as a model substrate of water-soluble macromolecules.
Initially, we developed a pipette-based intranasal administration protocol using temporarily openable masks, which enabled us to perform reliable administration to animals under stable anesthesia. Using this system, [14C]-inulin could be delivered to the brain with little experimental error.
We subsequently developed an intranasal administration protocol entailing reverse cannulation from the airway side through the esophagus, which was developed to minimize the effects of mucociliary clearance (MC). This technique led to significantly higher levels of [14C]-inulin, which was quantitatively detected in the olfactory bulb, cerebrum, and medulla oblongata, than the pipette method. This appears to be because retention of the drug solution in the nasal cavity was substantially increased by active administration using a syringe pump in a direction opposite to the MC into the nasal cavity.
In conclusion, the two methods of intranasal administration developed in this study can be expected to be extremely useful techniques for evaluating pharmacokinetics in rodents. The reverse cannulation method, in particular, could be useful for evaluating the full potential of nose-to-brain delivery of drug candidates.

Here, we describe two novel methods of stable intranasal administration under inhalation anesthesia with minimal physical stress for experimental animals. We also describe a method for quantitative evaluation of drug distribution levels in the brain via the nose-to-brain pathway using radiolabeled [14C]-inulin as a model substrate of water-soluble macromolecules.

Intranasal administration has been reported to be a potential pathway for nose-to-brain delivery of therapeutic agents that circumvents the blood-brain ...

Functional Assessment of the Donor Heart During Ex Situ Perfusion: Insights from Pressure-Volume Loops and Surface Echocardiography

Heart transplantation remains the gold standard treatment for advanced heart failure. However, the current critical organ shortage has resulted in the allocation of a growing number of donor hearts with extended criteria. These marginal grafts are associated with a high risk of primary graft failure and may benefit from ex situ perfusion before transplant. This technology allows for extended organ preservation using warm oxygenated blood perfusion with continuous metabolic monitoring. The only NESP device currently available for clinical practice perfuses the organ in an unloaded non-working state, which does not allow for functional assessment of the beating heart. We therefore developed an original platform of NESP in working mode conditions with adjustment of left ventricular preload and afterload. This protocol was applied in porcine hearts. Ex situ functional assessment of the heart was achieved with intracardiac conductance catheterization and surface echocardiography. Along with a description of the experimental protocol, we herein report the main results, as well as pearls and pitfalls associated with the acquisition of pressure-volume loops and myocardial power during NESP. Correlations between hemodynamic findings and ultrasound variables are of major interest, especially for further rehabilitation of donor hearts before transplantation. This protocol aims to improve the assessment of donor hearts to both increase the donor pool and reduce the incidence of primary graft failure.

Functional Assessment of the Donor Heart During Ex Situ Perfusion: Insights from Pressure-Volume Loops and Surface Echocardiography

A reliable noninvasive approach for functional assessment of the donor heart during normothermic ex situ heart perfusion (NESP) is lacking. We herein describe a protocol for ex situ assessment of myocardial performance using the epicardial echocardiography and conductance catheter method.

Heart transplantation remains the gold standard treatment for advanced heart failure. However, the current critical organ shortage has resulted in the ...

Partial Sciatic Nerve Ligation: A Mouse Model of Chronic Neuropathic Pain to Study the Antinociceptive Effect of Novel Therapies

Management of chronic pain remains challenging to this day, and current treatments are associated with adverse effects, including tolerance and addiction. Chronic neuropathic pain results from lesions or diseases in the somatosensory system. To investigate potential therapies with reduced side effects, animal pain models are the gold standard in preclinical studies. Therefore, well-characterized and well-described models are crucial for the development and validation of innovative therapies. 
Partial ligation of the sciatic nerve (pSNL) is a procedure that induces chronic neuropathic pain in mice, characterized by mechanical and thermal hypersensitivity, ongoing pain, and changes in limb temperature, making this model a great fit to study neuropathic pain preclinically. pSNL is an advantageous model to study neuropathic pain as it reproduces many symptoms observed in humans with neuropathic pain. Furthermore, the surgical procedure is relatively fast and straightforward to perform. Unilateral pSNL of one limb allows for comparison between the ipsilateral and contralateral paws, as well as evaluation of central sensitization. 
To induce chronic neuropathic hypersensitivity, a 9-0 non-absorbable nylon thread is used to ligate the dorsal third of the sciatic nerve. This article describes the surgical procedure and characterizes the development of chronic neuropathic pain through multiple commonly used behavioral tests. As a plethora of innovative therapies are now being investigated to treat chronic pain, this article provides crucial concepts for standardization and an accurate description of surgeries required to induce neuropathic pain.

Partial sciatic nerve ligation induces long-lasting chronic neuropathic pain, characterized by exaggerated responses to thermal and mechanical stimuli. This mouse model of neuropathic pain is commonly used to study innovative therapies for pain management. This article describes in detail the surgical procedure to improve standardization and reproducibility.

Management of chronic pain remains challenging to this day, and current treatments are associated with adverse effects, including tolerance and addiction. ...

Mongolian Gerbils as an Animal Model of Wound Healing

Corneal wound healing studies have been conducted for a long time and have helped to reduce suffering and develop treatments that contribute to improving patients' eye health. Historically, corneal healing has been studied in rodents such as mice and rats, but these models might not completely mimic human disorders. However, information on other rodents such as Mongolian gerbils (Meriones unguiculatus) is scant in corneal research.
Here, we describe a technique to develop a novel animal model for studying corneal healing after photorefractive keratectomy. Due to the limited literature available on the cornea of M. unguiculatus, we also describe a histological analysis of the normal cornea. These research techniques can also be employed in the study of eye diseases because of the similarity between the corneas of Mongolian gerbils and humans in terms of genetics, anatomy, and physiology.

This article describes a new animal model developed to study the anatomy and histology of the cornea and its healing processes. This new animal model uses the Mongolian gerbil, which has a cornea with many similarities to the human cornea.

Corneal wound healing studies have been conducted for a long time and have helped to reduce suffering and develop treatments that contribute to improving ...

Hickman Catheter for Long-Term Vascular Access in Swine

Hickman Catheter Use for Long-Term Vascular Access in a Preclinical Swine Model

Central venous catheters (CVCs) are invaluable devices in large animal research as they facilitate a wide range of medical applications, including blood monitoring and reliable intravenous fluid and drug administration. Specifically, the tunneled multi-lumen Hickman catheter (HC) is commonly used in swine models due to its lower extrication and complication rates. Despite fewer complications relative to other CVCs, HC-related morbidity presents a significant challenge, as it can significantly delay or otherwise negatively impact ongoing studies. The proper insertion and maintenance of HCs is paramount in preventing these complications, but there is no consensus on best practices. The purpose of this protocol is to comprehensively describe an approach for the insertion and maintenance of a tunneled HC in swine that mitigates HC-related complications and morbidity. The use of these techniques in &gt;100 swine has resulted in complication-free patent lines up to 8 months and no catheter-related mortality or infection of the ventral surgical site. This protocol offers a method to optimize the lifespan of the HC and guidance for approaching issues during use.

Author Spotlight: Hickman Catheter Use for Long-Term Vascular Access in a Preclinical Swine Model  

A reliable and reproducible approach for the insertion and maintenance of a tunneled Hickman catheter for long-term vascular access in swine is described. Placement of a central venous catheter allows for convenient daily sampling of whole blood from awake animals and intravenous administration of medication and fluids.

Central venous catheters (CVCs) are invaluable devices in large animal research as they facilitate a wide range of medical applications, including blood ...