Name: establishment of deep hypothermic circulatory arrest in rats
Uploaded: 2022-12-16T12:30:00.000+00:00
Duration: 8 min 39 s
Description: Watch this Scientific Journal Video about Establishment of Deep Hypothermic Circulatory Arrest in Rats at JoVE.com

The authors thank Liang Zhang for helping to collect the video data during the experiment. This study was supported by the National Natural Science Foundation of China (Grant number: 82070479) and the Fundamental Research Funds for the Central Universities (Grant number: 3332022128).

The protocols underwent an institutional review and received approval from the Institutional Animal Care and Use Committee, Fuwai Hospital, Chinese Academy of Medical Sciences (FW-2021-0005). All the experimental procedures were performed in accordance with the Guide for the Care and Use of Laboratory Animals published by the National Institutes of Health.
NOTE: Male Sprague-Dawley rats (weight: 500-600 g, age: 12-14 weeks) were kept under standard laboratory conditions with free access to food and water. The rats were randomly allocated into two groups (n = 6, each group): the DHCA group, and the normal temperature CPB group (NtCPB group).
1. Preparatory work
<ol>
	<li>Sterilize the surgical instruments (forceps, scissors, micro-forceps, an electrocoagulator, a shaver, etc.) before the experiment (Figure 1).</li>
	<li>Ensure the availability of the consumables, which include 2-0 silk, a 16 G cannula (endotracheal catheter), a 22 G cannula, a homemade 16-G cannula (multi-orifice intravenous catheter), injection syringes, gauze, and tape. 
	NOTE: For the homemade 16 G cannula, use a scalpel to cut two or three orifices of 2 mm diameter at the tip of the cannula, which will help to make the venous drainage smoother.</li>
	<li>Ensure the availability of sevoflurane, 2% lidocaine, saline, heparin (5 IU/mL, 250 IU/mL), epinephrine (40 &#181;g/mL), norepinephrine (20 &#181;g/mL), hydroxyethyl starch, and bicarbonate.</li>
	<li>Ensure the DHCA circuits contain a reservoir (modified from Murphy&#39;s dropper), a roller pump, a heat exchanger, a membrane oxygenator, connecting tubes, and a water tank (Figure 2). Connect the circuit, and mix 12 mL of hydroxyethyl starch with 1 mL of heparin sodium (250 IU) and 1 mL of saline. Prime the circuit with 14 mL of the priming solution with the roller pump gently rotating (10-40 mL/min). 
	NOTE: The reservoir is remolded from a blood transfusion device with Murphy&#39;s dropper. The venous inflow part of the dropper remains at 10-15 cm, and the venous outlet part remains at 10 cm.</li>
</ol>
2. Anesthesia and cannulation
<ol>
	<li>Anesthetize the rats with 2%-3% sevoflurane, and then test for the lack of the conjunctival reflex and muscle relaxation after the rat loses consciousness. 
	NOTE: The conjunctival reflex refers to the instant closure of the eyelid whenever the cornea is touched. Use a cotton swab to touch the cornea slightly. When the anesthesia depth is sufficient, the eyelids will not close.</li>
	<li>Perform endotracheal intubation with a 16 G cannula after the conjunctival reflex disappears and no muscular resistance is observed. Connect the tube to a ventilator, and set the parameters by clicking the buttons on the ventilator (tidal volume: 1.0-1.2 mL/100g, heart rate: 80 beats per minute [bpm], I:E = 1:1, inspired oxygen fraction: 60%).</li>
	<li>Put an electric heating blanket under the rat, and fix the rat with tape. Apply ophthalmic ointment to the eyes to prevent dryness. Shave the hair on the left inguinal region, right cervical region, and tail with a shaver. Then, disinfect the skin three times with iodine and alcohol.</li>
	<li>Check the depth of anesthesia before moving to the next steps. If the respiratory rate is higher than that set by the ventilator (80 bpm), or if there is muscle rigidity, then increase the output concentration of sevoflurane. 
	NOTE: When the depth of anesthesia is adequate, the respiratory rhythm should be synchronized with the ventilator, and the muscles should be completely relaxed without tension. Check the depth of anesthesia every 30 min to ensure that the rat is not experiencing any return of consciousness throughout the procedure.</li>
	<li>Use a scalpel to cut the skin at the left inguinal region (approximately 1 cm), and dissect the muscle and tissue softly to expose the left femoral vein and artery. Separate the artery carefully.</li>
	<li>Cannulate a 22 G intravenous catheter into the left femoral artery. Ligate the artery and catheter with a 2-0 silk (at the region of cannulation). Use saline-containing heparin (5 UI/mL) to flush the cannula to avoid clotting. Connect the catheter with the pressure sensor to monitor the blood pressure.</li>
	<li>Cut the skin of the tail (approximately 1.5 cm), and then use a scalpel to cut the superficial fascia of the tail artery to expose the tail artery, which is in the middle of the surgical field.</li>
	<li>Cannulate the tail artery with a 22 G intravenous catheter. Ligate the artery and catheter with a 2-0 silk (at the region of cannulation). Use saline-containing heparin (5 UI/mL) to flush the catheter to avoid clotting. 
	NOTE: When cannulating the intravenous catheter, the left hand holds the artery/vein with forceps, and the right hand pierces the artery/vein with the needle inside the catheter and then puts the cannula into the artery.</li>
	<li>Cut the skin on the right jugular vein (approximately 2 cm), and then separate the muscle and tissue to expose the vein. Insert a 16 G homemade multi-orifice intravenous catheter into the right external jugular vein, and put it into the right inferior vena cava or the right atrium carefully. 
	NOTE: The left femoral vein and artery are under the surface of the left inguinal region. The vein is thicker than the artery, and the blood color of the arteries is bright red. The right jugular vein is in the middle of the right cervical region; when the skin is cut and the muscles are separated, the vein can be seen (approximately 0.3-0.4 cm wide). When the tip of the catheter touches the right atrium, the wave of blood pressure will fluctuate. Then, after pulling the catheter back a little bit, the tip of the catheter will be in the superior vena cava.</li>
	<li>Administer heparin sodium (500 IU/kg) via the right external vein. Cover each cannulated region with moist gauze to avoid contamination. 
	&#8203;NOTE: Put a box under the operating table to elevate it about 40 cm.</li>
</ol>
3. DHCA initiation
<ol>
	<li>Connect the DHCA circuit with the catheter in the tail artery first, and keep the pump flow rate at 1-2 mL/min. Then, connect the reservoir with the catheter in the right external jugular vein. Make sure there is always a blood level of about 1 cm in the reservoir.</li>
	<li>Turn on the water tank, and set the water temperature at 37 &#176;C first.</li>
	<li>After the blood pressure is stable, gently increase the pump flow up to 80-100 mL/kg/min to pump the blood.</li>
</ol>
4. Cooling
<ol>
	<li>Set the room temperature to around 20 &#176;C. Put ice cubes in disposable gloves, and then place them on the rat&#39;s head and sides. Adjust the temperature of the tank in real-time according to the rectal temperature of the rats.</li>
	<li>Collect 0.1 mL of blood from the left femoral artery, and place it on the blood gas machine for blood gas analysis. Change the relevant parameters of the ventilator appropriately according to the results of the blood gas analysis (e.g., PaCO2). 
	&#8203;NOTE: The heart rate and blood pressure may change, and the pump flow rate should be adjusted accordingly. The temperature gradient between the water tank and the rat needs to be less than 10 &#176;C. Make sure the temperature can be reduced to 15-20 &#176;C within 30 min. The normal range of PaCO2 is 35-45 mmHg. If the blood gas results show a lower PaCO2, one may decrease the tidal volume and vice versa.</li>
</ol>
5. Deep hypothermic circulatory arrest
<ol>
	<li>When the rectal temperature drops to 15-20 &#176;C, change the disposable gloves (containing ice) to ensure the maintenance of deep hypothermia during the circulatory arrest.</li>
	<li>Stop the roller pump, keep the reservoir in contact with the environment, and drain the blood slowly from the external jugular vein to the reservoir.</li>
	<li>Pay attention to the blood pressure waveform. When the blood pressure and the heart beat rate are 0, stop the drainage, and keep the reservoir closed. Turn off the ventilator. 
	&#8203;NOTE: The duration of the circulatory arrest varies according to the purpose of the experiment.</li>
</ol>
6. Warm-up and reperfusion
<ol>
	<li>Remove all the disposable gloves, and increase the room temperature to 25 &#176;C. Restore the membrane oxygenator ventilation while keeping the venous drainage tube clipping. Turn on the roller pump to make sure the blood in the reservoir slowly goes back to the rat&#39;s body.</li>
	<li>Turn on the ventilator. Once the blood level in the reservoir remains at 1 cm, loosen the drainage tube, and drain the blood from the right atrium to the reservoir slowly.</li>
	<li>Turn on the heating lamp, the heating pad, and the water tank. Set the temperature of the water tank to 25 &#176;C firstly, and then adjust its outlet temperature in a timely manner according to the rectal temperature of the rat. 
	NOTE: The heating lamp should be directed at the large blood vessels in the rat thoracic cavity, and it should be kept at a certain distance to avoid burning the tissues. Pay attention to the temperature difference between the outlet temperature and the rat&#39;s rectal temperature (&#60;10 &#176;C). If necessary, test the blood gas, and then adjust the ventilator parameters accordingly, and administer bicarbonate, electrolytes, etc.</li>
	<li>Remove the heating lamp after the rectal temperature returns to 34 &#176;C. 
	&#8203;NOTE: This step, as a continuation of the rapid rewarming process, should be slow. At this stage, the equipment parameters of the sevoflurane vaporizer, mechanical ventilator, and roller pump can be restored to the levels at the beginning of the CPB.</li>
</ol>
7. Weaning off the CPB
<ol>
	<li>Slowly and gradually reduce the roller pump flow rate, and adjust the venous drainage speed until the flow rate reduces to 1 mL/min. 
	NOTE: Each flow rate adjustment should be observed for 3-5 min.</li>
	<li>Keep the reservoir in contact with the environment (by taking the reservoir cap off). Infuse the remaining blood in the circuit with a flow rate of 1 mL/min.</li>
	<li>Stop the membrane oxygenation and the roller pump.</li>
	<li>Euthanize the rat after a period of mechanical ventilation under deep anesthesia. 
	NOTE: This is a terminal procedure. The duration between weaning off the CPB and euthanasia varies according to the different study protocols. Remember to disinfect the wounds with iodine and alcohol and then cover each cannulated region with moist gauze to avoid contamination before euthanasia. Increase the output concentration of sevoflurane to increase the depth of anesthesia.</li>
</ol>

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The authors have nothing to disclose.

Cannulation is the most fundamental procedure for establishing DHCA in rats. Before cannulation, soaking the artery with 0.5 mL of 2% lidocaine will make it easier to cannulate. After cannulation, heparinization with 500 IU/kg heparin via the external jugular vein is necessary to avoid microthrombus formation17. We have repeatedly found that this dose of heparin can achieve the goal of an activated clotting time (ACT) &gt;480 s. The rewarming period is the most difficult part. It took mor...

Deep hypothermic circulatory arrest (DHCA) has been used in cardiac surgery since 19531. DHCA involves reducing the patient&#39;s core temperature to profoundly hypothermic levels (15-22 &#176;C) before globally interrupting the blood flow to the body2. The circulatory arrest can provide a relatively bloodless operating field. Deep hypothermia decreases the metabolism, especially in the brain and myocardium, which is an effective method of protection against ischemia3. DHCA is commonly applied during surgeries for complex congenital heart disease, aortic arch disease, and even renal or adrenal tumors with a vena cava thrombus4,5. Therefore, establishing DHCA animal models provides an important reference for the refinement of the procedure and the prevention of complications in clinical settings.
Although models can be established with canines6, rabbits7, and other animals, it is preferable to use rats because of their operability and low cost. The DHCA rat model was described for the first time in 2006 by Jungwirth et al.8. It was found that the duration of circulatory arrest had an impact on the neurologic outcomes. Since then, DHCA rat models have been investigated broadly. It has been clarified that DHCA could provoke systemic inflammatory response syndrome (SIRS)9. In subsequent studies, pharmacologists found that the DHCA-related neuroinflammation induced by SIRS could be attenuated by resveratrol10 and triptolide11. Our team also found that DHCA-related neuroinflammation could be attenuated by inhibiting the cold-inducible RNA-binding protein12. In the cardiovascular system, superoxide dismutase has a cardioprotective effect on ischemia/reperfusion (I/R) injuries during DHCA13. These results expanded the understanding of DHCA-related pathophysiologic processes and offered new directions for improving the outcomes of DHCA. However, the results regarding endotoxemia, oxidative stress, and autophagy after DHCA are inconclusive. DHCA uses the same operational technology as the cardiopulmonary bypass (CPB)14, but its management strategy is different, and the steps to generate DHCA differ across various teams8,9,10,11. The present study aims to provide a method for establishing the DHCA procedure in rats.

<table><tbody><tr><td>Heat Exchanger</td><td>Xi&amp;rsquo;an Xijing Medical Appliance Co., Ltd</td><td>Animal-M</td><td></td></tr><tr><td>Membrane Oxygenator</td><td>Dongguan Kewei Medical Instrument Co., Ltd.</td><td>Micro-M</td><td></td></tr><tr><td>Monitor</td><td>Chengdu Techman Co., Ltd</td><td>BL-420s</td><td></td></tr><tr><td>Roller Pump</td><td>Changzhou Prefluid Technology Co.,Ltd</td><td>BL100</td><td></td></tr><tr><td>SD Rat</td><td>HFK Bioscience Co.,Ltd.</td><td>/</td><td></td></tr><tr><td>Sevoflurane</td><td>Maruishi Pharmaceutical Co. Ltd</td><td>H20150020</td><td></td></tr><tr><td>Shaver</td><td>Hangzhou Huayuan Pet Products Co.,Ltd.</td><td>/</td><td></td></tr><tr><td>Vaporizer</td><td>SPACECABS</td><td>/</td><td></td></tr><tr><td>Ventilator</td><td>Shanghai Alcott Biotech Co., Ltd</td><td>ALC-V8S</td><td></td></tr><tr><td>Water Tank</td><td>Maquet Critical Care AB</td><td>Jostra HCU20-600</td><td></td></tr></tbody></table>

establishment of deep hypothermic circulatory arrest in rats

Deep hypothermic circulatory arrest (DHCA) is routinely applied during surgeries for complex congenital heart disease and aortic arch disease. The present study aims to provide a method for establishing DHCA in rats. To evaluate the impact of the DHCA process on vital signs, a normal temperature cardiopulmonary bypass (CPB) rat model without circulatory arrest was used as a control. As expected, DHCA led to a significant decrease in body temperature and mean arterial blood pressure. The blood gas analysis indicated that DHCA increased lactic acid levels but did not influence the blood pH and the concentrations of hemoglobin, hematocrit, Na+, Cl&#8722;, K+, and glucose. Furthermore, compared with the normal temperature CPB rats, the results of the transmission electron microscopy showed a mild increase in hippocampal autophagosomes in the DHCA rats.

As the control group, the normal temperature CPB (NtCPB) rats without circulatory arrest showed a stable mean arterial blood pressure (MAP) and body temperature during the whole procedure, while the MAP of the DHCA rats decreased during the cardiac arrest (p &#60; 0.01, Figure 3A). The temperature of the DHCA rats dropped quickly during the cooling phase and recovered gradually during the rewarming phase. When weaning the rats off the DHCA circuits, the temperature of the DHCA rats ...

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Establishment of Deep Hypothermic Circulatory Arrest in Rats

This protocol presents the establishment of deep hypothermic circulatory arrest in rats, which can be applied to investigate systemic inflammatory response syndrome, ischemia/reperfusion injury, oxidative stress, neuroinflammation, etc.

Deep hypothermic circulatory arrest (DHCA) is routinely applied during surgeries for complex congenital heart disease and aortic arch disease. The present ...

establishment-of-deep-hypothermic-circulatory-arrest-in-rats

Research

JoVE Journal

Immunology and Infection

2.1K Views.  Peking Union Medical College. This protocol presents the establishment of deep hypothermic circulatory arrest in rats, which can be applied to investigate systemic inflammatory response syndrome, ischemia/reperfusion injury, oxidative stress, neuroinflammation, etc. 

Video: Establishment of Deep Hypothermic Circulatory Arrest in Rats

Normothermic Cardiac Arrest and Cardiopulmonary Resuscitation: A Mouse Model of Ischemia-Reperfusion Injury

Acute Kidney Injury (AKI) is a common, highly lethal, complication of critical illness which has a high mortality1-4 and which is most 
frequently caused by whole-body hypoperfusion.5,6 Successful reproduction of whole-body hypoperfusion in rodent models has been fraught with 
difficulty.7-9,9,10 Models which employ focal ischemia have repeatedly demonstrated results which do not translate to the clinical setting, and larger 
animal models which allow for whole body hypoperfusion lack access to the full toolset of genetic manipulation possible in the mouse.11,12 However, in recent 
years a mouse model of cardiac arrest and cardiopulmonary resuscitation has emerged which can be adapted to model AKI.13 This model reliably reproduces 
physiologic, functional, anatomic, and histologic outcomes seen in clinical AKI, is rapidly repeatable, and offers all of the significant advantages of a murine surgical 
model, including access to genetic manipulative techniques, low cost relative to large animals, and ease of use. Our group has developed extensive experience 
with use of this model to assess a number of organ-specific outcomes in AKI.14,15

A powerful model for perioperative and critical care related acute kidney injury is presented. Using whole body hypoperfusion induced by cardiac arrest it is possible to nearly replicate the histologic and functional changes of clinical AKI.

Acute Kidney Injury (AKI) is a common, highly lethal, complication of critical illness which has a high mortality1-4 and which is most 
frequently caused ...

Medicine

2-Vessel Occlusion/Hypotension: A Rat Model of Global Brain Ischemia

Cardiac arrest followed by resuscitation often results in dramatic brain damage caused by ischemia and subsequent reperfusion of the brain. Global brain ischemia produces damage to specific brain regions shown to be highly sensitive to ischemia 1. Hippocampal neurons have higher sensitivity to ischemic insults compared to other cell populations, and specifically, the CA1 region of the hippocampus is particularly vulnerable to ischemia/reperfusion 2.
The design of therapeutic interventions, or study of mechanisms involved in cerebral damage, requires a model that produces damage similar to the clinical condition and in a reproducible manner. Bilateral carotid vessel occlusion with hypotension (2VOH) is a model that produces reversible forebrain ischemia, emulating the cerebral events that can occur during cardiac arrest and resuscitation. We describe a model modified from Smith et al. (1984) 2, as first presented in its current form in Sanderson, et al. (2008) 3, which produces reproducible injury to selectively vulnerable brain regions 3-6. The reliability of this model is dictated by precise control of systemic blood pressure during applied hypotension, the duration of ischemia, close temperature control, a specific anesthesia regimen, and diligent post-operative care. An 8-minute ischemic insult produces cell death of CA1 hippocampal neurons that progresses over the course of 6 to 24 hr of reperfusion, while less vulnerable brain regions are spared. This progressive cell death is easily quantified after 7-14 days of reperfusion, as a near complete loss of CA1 neurons is evident at this time.
In addition to this brain injury model, we present a method for CA1 damage quantification using a simple, yet thorough, methodology. Importantly, quantification can be accomplished using a simple camera-mounted microscope, and a free ImageJ (NIH) software plugin, obviating the need for cost-prohibitive stereology software programs and a motorized microscopic stage for damage assessment.

Bilateral carotid occlusion coupled with systemic hypotension produces global brain ischemia in the rat, resulting in damage to the hippocampus with reproducible severity. Animal subjects are impaired with predictable patterns of brain damage, they recover expediently, and mortality rates are comparatively low.

Cardiac arrest followed by resuscitation often results in dramatic brain damage caused by ischemia and subsequent reperfusion of the brain. Global brain ...

Remote Limb Ischemic Preconditioning:  A Neuroprotective Technique in Rodents

Sublethal ischemia protects tissues against subsequent, more severe ischemia through the upregulation of endogenous mechanisms in the affected tissue. Sublethal ischemia has also been shown to upregulate protective mechanisms in remote tissues. A brief period of ischemia (5-10 min) in the hind limb of mammals induces self-protective responses in the brain, lung, heart and retina. The effect is known as remote ischemic preconditioning (RIP). It is a therapeutically promising way of protecting vital organs, and is already under clinical trials for heart and brain injuries. This publication demonstrates a controlled, minimally invasive method of making a limb &#8211; specifically the hind limb of a rat &#8211; ischemic. A blood pressure cuff developed for use in human neonates is connected to a manual sphygmomanometer and used to apply 160 mmHg pressure around the upper part of the hind limb. A probe designed to detect skin temperature is used to verify the ischemia, by recording the drop in skin temperature caused by pressure-induced occlusion of the leg arteries, and the rise in temperature which follows release of the cuff. This method of RIP affords protection to the rat retina against bright light-induced damage and degeneration.

Remote ischemic preconditioning (RIP) is a method of conditioning tissues against damaging stress. We have established a method of remote ischemia at the hind limb, by inflating a sphygmomanometer cuff for 5-10 min. The neuroprotective capabilities of RIP have been demonstrated in a model of retinal degeneration in rodents.

Sublethal ischemia protects tissues against subsequent, more severe ischemia through the upregulation of endogenous mechanisms in the affected tissue. ...

A Recovery Cardiopulmonary Bypass Model Without Transfusion or Inotropic Agents in Rats

Cardiopulmonary bypass (CPB) is indispensable in cardiovascular surgery. Despite the dramatic refinement of CPB technique and devices, multi-organ complications related to prolonged CPB still compromise the outcome of cardiovascular surgeries, and may worsen postoperative morbidity and mortality. Animal models recapitulating the clinical usage of CPB enable the clarification of the pathophysiological processes that occur during CPB, and facilitate pre-clinical studies to develop strategies protecting against these complications. Rat CPB models are advantageous because of their greater cost-effectiveness, convenient experimental processes, abundant testing methods at the genetic or protein levels, and genetic consistency. They can be used for investigating the immune system activation and synthesis of proinflammatory cytokines, compliment activation, and production of oxygen free radicals. The rat models have been refined and have gradually taken the place of large-animal models. Here, we describe a simple CPB model without transfusion and/or inotropic agents in a rat. This recovery model allows the study of the long-term multiple organ sequelae of CPB.

Here, we present a protocol to describe a simple recovery cardiopulmonary bypass model without transfusion or inotropic agents in a rat. This model allows the study of the long-term multiple organ sequelae of cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) is indispensable in cardiovascular surgery. Despite the dramatic refinement of CPB technique and devices, multi-organ ...

Cardiopulmonary Bypass in a Mouse Model: A Novel Approach

As prolonged cardiopulmonary bypass becomes more essential during cardiac interventions, an increasing clinical demand arises for procedure optimization and for minimizing organ damage resulting from prolonged extracorporal circulation. The goal of this paper was to demonstrate a fully functional and clinically relevant model of cardiopulmonary bypass in a mouse. We report on the device design, perfusion circuit optimization, and microsurgical techniques. This model is an acute model, which is not compatible with survival due to the need for multiple blood drawings. Because of the range of tools available for mice (e.g., markers, knockouts, etc.), this model will facilitate investigation into the molecular mechanisms of organ damage and the effect of cardiopulmonary bypass in relation to other comorbidities.

This paper describes how to perform cardiopulmonary bypass in mice. This novel model will facilitate the investigation of the molecular mechanisms involved in organ damage.

As prolonged cardiopulmonary bypass becomes more essential during cardiac interventions, an increasing clinical demand arises for procedure optimization ...

Establishment of Acute Pontine Infarction in Rats by Electrical Stimulation

Pontine infarction is the most common stroke subtype in the posterior circulation, while there lacks a rodent model mimicking pontine infarction. Provided here is a protocol for successfully establishing a rat model of acute pontine infarction. Rats weighing about 250 g are used, and a probe with an insulated sheath is injected into the pons using a stereotaxic apparatus. A lesion is produced by the electrical stimulation with a single pulse. The Longa score, Berderson score, and beam balance test are used to assess neurological deficits. Additionally, the adhesive-removal somatosensory test is used to determine sensorimotor function, and the limb placement test is used to evaluate proprioception. MRI scans are then used to assess the infarction in vivo, and TTC staining is used to confirm the infarction in vitro. Here, a successful infarction is identified that is located in the anterolateral basis of the rostral pons. In conclusion, a new method is described to establish an acute pontine infarction rat model.

Presented here is a protocol for establishing acute pontine infarction in a rat model via electrical stimulation with a single pulse.

Pontine infarction is the most common stroke subtype in the posterior circulation, while there lacks a rodent model mimicking pontine infarction. Provided ...

Neuroscience

The Superficial Inferior Epigastric Artery Axial Flap to Study Ischemic Preconditioning Effects in a Rat Model

Fasciocutaneous flaps (FCF) have become the gold standard for complex defect reconstruction in plastic and reconstructive surgery. This muscle-sparing technique allows transferring vascularized tissues to cover any large defect. FCF can be used as pedicled flaps or as free flaps; however, in the literature, failure rates for pedicled FCF and free FCF are above 5%, leaving room for improvement for these techniques and further knowledge expansion in this area. Ischemic preconditioning (I.P.) has been widely studied, but the mechanisms and the optimization of the I.P. regimen are yet to be determined. This phenomenon is indeed poorly explored in plastic and reconstructive surgery. Here, a surgical model is presented to study the I.P. regimen in a rat axial fasciocutaneous flap model, describing how to safely and reliably assess the effects of I.P. on flap survival. This article describes the complete surgical procedure, including suggestions to improve the reliability of this model. The objective is to provide researchers with a reproducible and reliable model to test various ischemic preconditioning regimens and assess their effects on flap survivability.

This protocol describes harvesting, suturing, and monitoring fasciocutaneous flaps in rats that allow for good visualization and manipulation of blood flow through the superficial inferior epigastric vessels by means of clamping and ligating the femoral vessels. This is critical for studies involving ischemic preconditioning.

Fasciocutaneous flaps (FCF) have become the gold standard for complex defect reconstruction in plastic and reconstructive surgery. This muscle-sparing ...

Short-Duration Hypothermia Induction in Rats using Models for Studies examining Clinical Relevance and Mechanisms

Therapeutic hypothermia (TH) is a powerful neuroprotective strategy that has provided robust evidence for neuroprotection in pre-clinical studies of neurological disorders. Despite strong pre-clinical evidence, TH has not shown efficacy in clinical trials of most neurological disorders. The only successful trials employing therapeutic hypothermia were related to cardiac arrest in adults and hypoxic ischemic injury in neonates. Further investigations into the parameters of its use, and study design comparisons between pre-clinical and clinical studies, are warranted. This article demonstrates two methods of short-duration hypothermia induction. The first method allows for rapid hypothermia induction in rats using ethanol spray and fans. This method works by cooling the skin, which has been less commonly used in clinical trials and may have different physiological effects. Cooling is much more rapid with this technique than is achievable in human patients due to differences in surface area to volume ratio. Along with this, a second method is also presented, which allows for a clinically achievable cooling rate for short-duration hypothermia. This method is easy to implement, reproducible and does not require active skin cooling.

This article describes two methods of whole-body short-duration hypothermia induction in rats. The first, rapid induction method, employs active cooling using fans and ethanol spray for a rapid decrease in temperature. The second method is a gradual cooling method. This is achieved using the combination of isoflurane anesthesia and the reduction of temperature settings on the homeothermic heat mat. This results in a gradual decrease in core body temperature without the use of any external cooling devices.&#160;

Therapeutic hypothermia (TH) is a powerful neuroprotective strategy that has provided robust evidence for neuroprotection in pre-clinical studies of ...

Tracheotomy-Based Endotracheal Intubation Protocol for Non-Survival Rat Models

Endotracheal Intubation via Tracheotomy and Subsequent Thoracotomy in Rats for Non-Survival Applications

Endotracheal intubation and subsequent ventilation are often basic requirements for translational research in rat models for various interventions that require controlled or high ventilation pressures or access to the thoracic cavity and organs. Conventional endoorotracheal intubation using the anatomically existing route through the mouth is well suited for survival experiments. However, this procedure poses some challenges, including generally higher levels of the required experience and technical skill, more advanced equipment, and greater time effort with relevant intubation failure rates and complications such as tracheal perforation, temporary systemic hypooxygenation, and relevant aerial leakage.
This manuscript, therefore, presents a detailed step-by-step protocol for endotracheal intubation through tracheotomy in non-survival rat models when guaranteed intubation success, constant oxygenation levels, high ventilation pressures, or open thoracotomy are required.
The protocol emphasizes the importance of meticulous surgical technique to ensure consistent and reliable outcomes, especially for researchers who are inexperienced or lack routine in the technique of endoorotracheal intubation via direct laryngoscopy. This procedure is, therefore, expected to minimize animal suffering and unnecessary animal losses.

Here we introduce a standardized procedure for endotracheal intubation via tracheotomy followed by thoracotomy in rats, aimed at enhancing the precision and reproducibility of non-survival applications requiring invasive ventilation and exposure of thoracic organs in in vivo rat models.

Endotracheal intubation and subsequent ventilation are often basic requirements for translational research in rat models for various interventions that ...

Study of Experimental Organ Donation Models for Lung Transplantation

Experimental models are important tools for understanding the etiological phenomena involved in various pathophysiological events. In this context, different animal models are used to study the elements triggering the pathophysiology of primary graft dysfunction after transplantation to evaluate potential treatments. Currently, we can divide experimental donation models into two large groups: donation after brain death and donation after circulatory arrest. In addition, the deleterious effects associated with hemorrhagic shock should be considered when considering animal models of organ donation. Here, we describe the establishment of three different lung donation models (post-brain death donation, post-circulatory death donation, and post-hemorrhagic shock donation) and compare the inflammatory processes and pathological disorders associated with these events. The objective is to provide the scientific community with reliable animal models of lung donation for studying the associated pathological mechanisms and searching for new therapeutic targets to optimize the number of viable grafts for transplantation.

The present study shows the establishment of three different lung donation models (post-brain death donation, post-circulatory death donation, and post-hemorrhagic shock donation). It compares the inflammatory processes and pathological disorders associated with these events.

Experimental models are important tools for understanding the etiological phenomena involved in various pathophysiological events. In this context, ...