Name: a reproducible intensive care unit-oriented endotoxin model in rats
Uploaded: 2021-02-20T15:00:00
Description: Watch this Scientific Journal Video about A Reproducible Intensive Care Unit-Oriented Endotoxin Model in Rats at JoVE.com

The authors would like to thank Beatrice Beck-Schimmer (MD) and Erik Schadde (MD) for their critical examination and their valuable contribution for this manuscript.

All experiments presented in this protocol were approved by the Veterinary Authorities of the Canton Zurich, Switzerland (approval numbers 134/2014 and ZH088/19). Moreover, all steps performed in this experiment were in accordance with the Guidelines on Experiments with Animals by the Swiss Academy of Medial Sciences (SAMS) and Guidelines of the Federation of European Laboratory Animal Science Associations (FELASA).
1. Anesthesia induction and animal monitoring
<ol>
	<li>Keep male Wistar rat...

<ol>
	<li>Hotchkiss, R. S., Karl, I. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pathophysiology+and+treatment+of+sepsis.">The pathophysiology and treatment of sepsis.</a> New England Journal of Medicine. 348 (2), 138-150 (2003).</li><li>Singer, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Third+International+Consensus+Definitions+for+Sepsis+and+Septic+Shock+(Sepsis-3).">The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3).</a> Journal of the American Medical Association. 315 (8), 801-810 (2016).</li><li>Vincent, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+the+worldwide+burden+of+critical+illness:+the+intensive+care+over+nations+(ICON)+audit.">Assessment of the worldwide burden of critical illness: the intensive care over nations (ICON) audit.</a> Lancet Respiratory Medicine. 2 (5), 380-386 (2014).</li><li>Fleischmann, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+Global+Incidence+and+Mortality+of+Hospital-treated+Sepsis.+Current+Estimates+and+Limitations.">Assessment of Global Incidence and Mortality of Hospital-treated Sepsis. Current Estimates and Limitations.</a> American Journal of Respiratory and Critical Care Medicine. 193 (3), 259-272 (2016).</li><li>Kumar, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Duration+of+hypotension+before+initiation+of+effective+antimicrobial+therapy+is+the+critical+determinant+of+survival+in+human+septic+shock.">Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock.</a> Critical Care Medicine. 34 (6), 1589-1596 (2006).</li><li>Gotts, J. E., Matthay, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sepsis:+pathophysiology+and+clinical+management.">Sepsis: pathophysiology and clinical management.</a> British Medical Journal. 353, (2016).</li><li>Akira, S., Takeda, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toll-like+receptor+signalling.">Toll-like receptor signalling.</a> Nature Reviews Immunology. 4 (7), 499-511 (2004).</li><li>Urner, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insight+into+the+beneficial+immunomodulatory+mechanism+of+the+sevoflurane+metabolite+hexafluoro-2-propanol+in+a+rat+model+of+endotoxaemia.">Insight into the beneficial immunomodulatory mechanism of the sevoflurane metabolite hexafluoro-2-propanol in a rat model of endotoxaemia.</a> Clinical and Experimental Immunology. 181 (3), 468-479 (2015).</li><li>Beck-Schimmer, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Which+Anesthesia+Regimen+Is+Best+to+Reduce+Morbidity+and+Mortality+in+Lung+Surgery?:+A+Multicenter+Randomized+Controlled+Trial.">Which Anesthesia Regimen Is Best to Reduce Morbidity and Mortality in Lung Surgery?: A Multicenter Randomized Controlled Trial.</a> Anesthesiology. 125 (2), 313-321 (2016).</li><li>Deitch, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+sepsis+and+shock:+a+review+and+lessons+learned.">Animal models of sepsis and shock: a review and lessons learned.</a> Shock. 9 (1), 1-11 (1998).</li><li>Buras, J. A., Holzmann, B., Sitkovsky, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+sepsis:+setting+the+stage.">Animal models of sepsis: setting the stage.</a> Nature Reviews Drug Discovery. 4 (10), 854-865 (2005).</li><li>Perretti, M., Duncan, G. S., Flower, R. J., Peers, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serum+corticosterone,+interleukin-1+and+tumour+necrosis+factor+in+rat+experimental+endotoxaemia:+comparison+between+Lewis+and+Wistar+strains.">Serum corticosterone, interleukin-1 and tumour necrosis factor in rat experimental endotoxaemia: comparison between Lewis and Wistar strains.</a> British Journal of Pharmacology. 110 (2), 868-874 (1993).</li><li>Marechal, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+glycocalyx+damage+during+endotoxemia+coincides+with+microcirculatory+dysfunction+and+vascular+oxidative+stress.">Endothelial glycocalyx damage during endotoxemia coincides with microcirculatory dysfunction and vascular oxidative stress.</a> Shock. 29 (5), 572-576 (2008).</li><li>Thiemermann, C., Ruetten, H., Wu, C. C., Vane, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+multiple+organ+dysfunction+syndrome+caused+by+endotoxin+in+the+rat:+attenuation+of+liver+dysfunction+by+inhibitors+of+nitric+oxide+synthase.">The multiple organ dysfunction syndrome caused by endotoxin in the rat: attenuation of liver dysfunction by inhibitors of nitric oxide synthase.</a> British Journal of Pharmacology. 116 (7), 2845-2851 (1995).</li><li>Osuchowski, M. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimum+quality+threshold+in+pre-clinical+sepsis+studies+(MQTiPSS):+an+international+expert+consensus+initiative+for+improvement+of+animal+modeling+in+sepsis.">Minimum quality threshold in pre-clinical sepsis studies (MQTiPSS): an international expert consensus initiative for improvement of animal modeling in sepsis.</a> Intensive Care Medicine Experimental. 6 (1), 26 (2018).</li><li>Fink, M. P., Heard, S. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+models+of+sepsis+and+septic+shock.">Laboratory models of sepsis and septic shock.</a> Journal of Surgical Research. 49 (2), 186-196 (1990).</li><li>Buras, J. A., Holzmann, B., Sitkovsky, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+sepsis:+Setting+the+stage.">Animal models of sepsis: Setting the stage.</a> Nature Reviews Drug Discovery. 4 (10), 854-865 (2005).</li><li>Balls, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+principles+of+humane+experimental+technique:+timeless+insights+and+unheeded+warnings.">The principles of humane experimental technique: timeless insights and unheeded warnings.</a> Altex-Alternatives to Animal Experimentation. 27 (2), 144-148 (2010).</li></ol>

The protocol described here allows for a highly reproducible, yet simple to learn sepsis model, which can be adapted according the research question. Essential in vivo data referring to organ function such as heart rate, blood pressure, and peripheral arterial oxygen saturation may be collected continuously, and blood sampling may be performed repetitively throughout the experiment. In addition, modifications with regard to fluid replacement protocols and vasopressor support can be installed. Given the hemodynamic stabil...

Sepsis and its more severe form, septic shock, are syndromes on the ground of an infection, resulting in an overshooting inflammatory reaction with the release of cytokines, leading to physiological and biochemical changes with a suppressed immune defense and fatal results1,2. This unbalanced inflammatory reaction results in organ dysfunction and organ failure in various vital organs such as lung, kidney, and liver. With 37%3, sepsis is one of the most common reasons for a patient to be admitted to an intensive care unit (ICU). Mortality of sepsis currently ranges around 20-30%4. Early and effective antibiotic treatment is of utmost importance5. Fluid and vasopressor resuscitation need to be installed early, other than that, treatment is purely supportive6.
Sepsis is defined as a proven or suspected infection with bacteria, fungi, viruses, or parasites, which is accompanied by organ dysfunction. Septic shock criteria are met when a further cardiovascular collapse irresponsive to fluid treatment alone, and a lactate level of more than 2 millimole/liter is present2. Sepsis related organ failure may occur in any organ, but is very common in the cardiovascular system, the brain, the kidney, the liver, and the lung. Most patients suffering from sepsis require endotracheal intubation to secure the patient&#39;s airway, to protect from aspiration, and to apply positive end expiratory ventilation with a high fraction of inspired oxygen to prevent or overcome hypoxia. In order to tolerate a tracheal tube and mechanical ventilation, patients usually require sedation.
Endotoxins, such as lipopolysaccharides (LPS) as a component of the membrane of gram negative bacteria induce a strong inflammatory reaction via the toll-like receptor (TLR) 47. Activation of a defined pathway ensures a stable inflammatory reaction. Cytokines like cytokine induced neutrophil chemoattractant protein 1 (CINC-1), monocyte chemoattractant protein 1 (MCP-1), and interleukin 6 (IL-6) are known as prognostic factors for severity and outcome in this model8. Intravenous LPS application has been successfully used to study various aspects of sepsis in rats8,9.
Treatment of sepsis is still a challenge, particularly due to the lack of predictive animal models. If endotoxemia with activation of systemic inflammation is an adequate model for the development of pharmacological therapies is debatable. However, with the well-known LPS-induced TLR 4 pathway important knowledge can be gained.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2-0 silk sutures</td>
			<td>Ethicon, Sommerville, NJ</td>
			<td>K833</td>
			<td>Standard surgical</td>
		</tr>
		<tr>
			<td>26 intravenous catheter</td>
			<td>Becton Dickinson, Franklin Lakes, NJ</td>
			<td>391349</td>
			<td>Standard anesthesia equipment</td>
		</tr>
		<tr>
			<td>6-0 LOOK black braided silk</td>
			<td>Surgical Specalities Corporation, Wyomissing, PA</td>
			<td>SP114</td>
			<td>Standard surgical</td>
		</tr>
		<tr>
			<td>Alaris Syringe Pump</td>
			<td>Bencton Dickinson</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Betadine</td>
			<td>Mundipharma, Basel, Switzerland</td>
			<td>7.68034E+12</td>
			<td>GTIN-number</td>
		</tr>
		<tr>
			<td>Curved fine tips microforceps</td>
			<td>World precision instruments (WPI), Sarasota, FL</td>
			<td>504513</td>
			<td>Facilitates vascular preparation</td>
		</tr>
		<tr>
			<td>Fine tips microforceps</td>
			<td>World precision instruments (WPI), Sarasota, FL</td>
			<td>501976</td>
			<td>Tips need to be polished regularly</td>
		</tr>
		<tr>
			<td>Infinity Delta XL Anesthesia monitoring</td>
			<td>Draeger, L&#252;beck, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane, 250 mL bottles</td>
			<td>Attane, Piramal, Mumbai, India</td>
			<td>LDNI 22098</td>
			<td>Standard vet. equipment</td>
		</tr>
		<tr>
			<td>Ketamine (Ketalar)</td>
			<td>Pfitzer, New York, NY</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Lipopolysaccharide (LPS) from Escherichia coli, serotype 055:B5</td>
			<td>Sigma, Buchs, Switzerland</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Q-tips small</td>
			<td>Carl Roth GmbH, Karlsruhe, Germany</td>
			<td>EH11.1</td>
			<td>Standard surgical</td>
		</tr>
		<tr>
			<td>Ringerfundin</td>
			<td>Bbraun, Melsungen, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tec-3 Isofluorane Vaporizer</td>
			<td>Ohmeda, GE-Healthcare, Chicago, IL</td>
			<td>not available anymore</td>
			<td>Standard vet. equipment</td>
		</tr>
		<tr>
			<td>Xylazine (Xylazin Streuli)</td>
			<td>Streuli AG, Uznach, Switzerland</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

a reproducible intensive care unit-oriented endotoxin model in rats

Sepsis and septic shock remain the leading cause of death in intensive care units. Despite significant improvements in sepsis management, mortality still ranges between 20 and 30%. Novel treatment approaches in order to reduce sepsis-related multiorgan failure and death are urgently needed. Robust animal models allow for one or multiple treatment approaches as well as for testing their effect on physiological and molecular parameters. In this article, a simple animal model is presented.
First, general anesthesia is induced in animals either with the use of volatile or by intraperitoneal anesthesia. After placement of an intravenous catheter (tail vein), tracheostomy, and insertion of an intraarterial catheter (tail artery), mechanical ventilation is started. Baseline values of mean arterial blood pressure, arterial blood oxygen saturation, and heart rate are recorded.
The injection of lipopolysaccharides (1 milligram/kilogram body weight) dissolved in phosphate-buffered saline induces a strong and reproducible inflammatory response via the toll-like receptor 4. Fluid corrections as well as the application of norepinephrine are performed based on well-established protocols.
The animal model presented in this article is easy to learn and strongly oriented towards clinical sepsis treatment in an intensive care unit with sedation, mechanical ventilation, continuous blood pressure monitoring, and repetitive blood sampling. Also, the model is reliable, allowing for reproducible data with a limited number of animals in accordance with the 3R (reduce, replace, refine) principles of animal research. While animal experiments in sepsis research cannot easily replaced, repetitive measurements allow for a reduction of animals and keeping septic animals anesthetized diminishes suffering.

The system presented allows for endotoxemia with hemodynamically stable animals as reported previously9. While the mean arterial pressure remains stable in animals with, and without LPS stimulation LPS treated animal develop characteristics of sepsis such as a negative base excess and a strong inflammatory reaction measured by plasma cytokines (6 hours after application) such as CINC-1 (867 ng/mL), MCP-1 (5027 ng/mL), and IL-6 (867 ng/mL)8, Figure 5</st...

Watch this Scientific Journal Video about A Reproducible Intensive Care Unit-Oriented Endotoxin Model in Rats at JoVE.com

A Reproducible Intensive Care Unit-Oriented Endotoxin Model in Rats

Here, we present a reproducible intensive care unit-oriented endotoxin model in rats.

Sepsis and septic shock remain the leading cause of death in intensive care units. Despite significant improvements in sepsis management, mortality still ...

Research

JoVE Journal

Medicine

Spectral Karyotyping to Study Chromosome Abnormalities in Humans and Mice with Polycystic Kidney Disease

Conventional method to identify and classify individual chromosomes depends on the unique banding pattern of each chromosome in a specific species being ...

A Murine Closed-chest Model of Myocardial Ischemia and Reperfusion

Surgical trauma by thoracotomy in open-chest models of coronary ligation induces an immune response which modifies different mechanisms involved in ...

Lavage-induced Surfactant Depletion in Pigs As a Model of the Acute Respiratory Distress Syndrome (ARDS)

Lavage-induced Surfactant Depletion in Pigs As a Model of the Acute Respiratory Distress Syndrome ARDS

Various animal models of lung injury exist to study the complex pathomechanisms of human acute respiratory distress syndrome (ARDS) and evaluate future ...

A Model of Cardiac Remodeling Through Constriction of the Abdominal Aorta in Rats

Heart failure is one of the leading causes of death worldwide. It is a complex clinical syndromethat includes fatigue, dyspnea, exercise intolerance, and ...

A Model to Simulate Clinically Relevant Hypoxia in Humans

In case of apnea, arterial partial pressure of oxygen (pO2) decreases, while partial pressure of carbon dioxide (pCO2) increases. To avoid damage to ...

Use of a Central Venous Line for Fluids, Drugs and Nutrient Administration in a Mouse Model of Critical Illness

This protocol describes a centrally catheterized mouse model of prolonged critical illness. We combine the cecal ligation and puncture method to induce ...

Observational Study Protocol for Repeated Clinical Examination and Critical Care Ultrasonography Within the Simple Intensive Care Studies

Longitudinal evaluations of critically ill patients by combinations of clinical examination, biochemical analysis and critical care ultrasonography (CCUS) ...

A Protocol to Set Up Needle-Free Connector with Positive Displacement on Central Venous Catheter in Intensive Care Unit

Needle-free connectors were initially designed and promoted to avoid blood exposure for healthcare workers. Some recent data suggest that the latest ...

Inducing Acute Lung Injury in Mice by Direct Intratracheal Lipopolysaccharide Instillation

Airway administration of lipopolysaccharide (LPS) is a common way to study pulmonary inflammation and acute lung injury (ALI) in small animal models. ...

Halogenated Agent Delivery in Porcine Model of Acute Respiratory Distress Syndrome via an Intensive Care Unit Type Device

Acute respiratory distress syndrome (ARDS) is a common cause of hypoxemic respiratory failure and death in critically ill patients, and there is an urgent ...