Name: injections of lipopolysaccharide into mice to mimic entrance of microbial-derived products after intestinal barrier breach
Uploaded: 2018-05-02T15:00:00
Description: Watch this Scientific Journal Video about Injections of Lipopolysaccharide into Mice to Mimic Entrance of Microbial-derived Products After Intestinal Barrier Breach at JoVE.com

JHN is supported by the Swiss National Foundation (SNSF 310030_146290).

Mice were bred and kept under specific pathogen-free (SPF) conditions in the animal facility of Department of Biomedicine, University of Basel (Basel, Switzerland). All mouse experiments were performed in accordance with the Swiss Federal and Cantonal regulations (animal protocol number 2816 [Canton of Basel-Stadt]).
1. Preparation of LPS Solution
<ol>
	<li>Open the stock of LPS purified from Escherichia coli 0111:B4 under sterile conditions and reconstitute it in water to the conce...

<ol>
	<li>Backhed, F., Ley, R. E., Sonnenburg, J. L., Peterson, D. A., Gordon, J. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Host-bacterial+mutualism+in+the+human+intestine.">Host-bacterial mutualism in the human intestine.</a> Science. 307, 1915-1920 (2005).</li><li>Abreu, M. T., 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=Mutations+in+NOD2+are+associated+with+fibrostenosing+disease+in+patients+with+Crohn's+disease.">Mutations in NOD2 are associated with fibrostenosing disease in patients with Crohn's disease.</a> Gastroenterology. 123, 679-688 (2002).</li><li>Liu, Y., 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=Immunocytochemical+evidence+of+Listeria,+Escherichia+coli,+and+Streptococcus+antigens+in+Crohn's+disease.">Immunocytochemical evidence of Listeria, Escherichia coli, and Streptococcus antigens in Crohn's disease.</a> Gastroenterology. 108, 1396-1404 (1995).</li><li>Schaffer, T., 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=Anti-Saccharomyces+cerevisiae+mannan+antibodies+(ASCA)+of+Crohn's+patients+crossreact+with+mannan+from+other+yeast+strains,+and+murine+ASCA+IgM+can+be+experimentally+induced+with+Candida+albicans.">Anti-Saccharomyces cerevisiae mannan antibodies (ASCA) of Crohn's patients crossreact with mannan from other yeast strains, and murine ASCA IgM can be experimentally induced with Candida albicans.</a> Inflamm Bowel Dis. 13, 1339-1346 (2007).</li><li>Sellon, R. K., 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=Resident+enteric+bacteria+are+necessary+for+development+of+spontaneous+colitis+and+immune+system+activation+in+interleukin-10-deficient+mice.">Resident enteric bacteria are necessary for development of spontaneous colitis and immune system activation in interleukin-10-deficient mice.</a> Infect Immun. 66, 5224-5231 (1998).</li><li>Gkouskou, K. K., Deligianni, C., Tsatsanis, C., Eliopoulos, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+gut+microbiota+in+mouse+models+of+inflammatory+bowel+disease.">The gut microbiota in mouse models of inflammatory bowel disease.</a> Front Cell Infect Microbiol. 4, 28 (2014).</li><li>Schaubeck, 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=Dysbiotic+gut+microbiota+causes+transmissible+Crohn's+disease-like+ileitis+independent+of+failure+in+antimicrobial+defence.">Dysbiotic gut microbiota causes transmissible Crohn's disease-like ileitis independent of failure in antimicrobial defence.</a> Gut. 65, 225-237 (2016).</li><li>Steinert, 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=The+Stimulation+of+Macrophages+with+TLR+Ligands+Supports+Increased+IL-19+Expression+in+Inflammatory+Bowel+Disease+Patients+and+in+Colitis+Models.">The Stimulation of Macrophages with TLR Ligands Supports Increased IL-19 Expression in Inflammatory Bowel Disease Patients and in Colitis Models.</a> J Immunol. 199, 2570-2584 (2017).</li><li>Gabele, E., 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=DSS+induced+colitis+increases+portal+LPS+levels+and+enhances+hepatic+inflammation+and+fibrogenesis+in+experimental+NASH.">DSS induced colitis increases portal LPS levels and enhances hepatic inflammation and fibrogenesis in experimental NASH.</a> J Hepatol. 55, 1391-1399 (2011).</li><li>Saunders, S. P., 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=C-type+lectin+SIGN-R1+has+a+role+in+experimental+colitis+and+responsiveness+to+lipopolysaccharide.">C-type lectin SIGN-R1 has a role in experimental colitis and responsiveness to lipopolysaccharide.</a> J Immunol. 184, 2627-2637 (2010).</li><li>Spadoni, I., 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=A+gut-vascular+barrier+controls+the+systemic+dissemination+of+bacteria.">A gut-vascular barrier controls the systemic dissemination of bacteria.</a> Science. 350, 830-834 (2015).</li><li>Balmer, M. 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=The+liver+may+act+as+a+firewall+mediating+mutualism+between+the+host+and+its+gut+commensal+microbiota.">The liver may act as a firewall mediating mutualism between the host and its gut commensal microbiota.</a> Sci Transl Med. 6, 237ra266 (2014).</li><li>Maier, R. V., Mathison, J. C., Ulevitch, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactions+of+bacterial+lipopolysaccharides+with+tissue+macrophages+and+plasma+lipoproteins.">Interactions of bacterial lipopolysaccharides with tissue macrophages and plasma lipoproteins.</a> Prog Clin Biol Res. 62, 133-155 (1981).</li><li>Lu, Y. C., Yeh, W. C., Ohashi, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LPS/TLR4+signal+transduction+pathway.">LPS/TLR4 signal transduction pathway.</a> Cytokine. 42, 145-151 (2008).</li><li>Deng, 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=Lipopolysaccharide+clearance,+bacterial+clearance,+and+systemic+inflammatory+responses+are+regulated+by+cell+type-specific+functions+of+TLR4+during+sepsis.">Lipopolysaccharide clearance, bacterial clearance, and systemic inflammatory responses are regulated by cell type-specific functions of TLR4 during sepsis.</a> J Immunol. 190, 5152-5160 (2013).</li><li>Kagan, J. 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=TRAM+couples+endocytosis+of+Toll-like+receptor+4+to+the+induction+of+interferon-beta.">TRAM couples endocytosis of Toll-like receptor 4 to the induction of interferon-beta.</a> Nat Immunol. 9, 361-368 (2008).</li><li>Akira, S., Uematsu, S., Takeuchi, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogen+recognition+and+innate+immunity.">Pathogen recognition and innate immunity.</a> Cell. 124, 783-801 (2006).</li><li>Cohen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+immunopathogenesis+of+sepsis.">The immunopathogenesis of sepsis.</a> Nature. 420, 885-891 (2002).</li><li>Suffredini, A. 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=Effects+of+recombinant+dimeric+TNF+receptor+on+human+inflammatory+responses+following+intravenous+endotoxin+administration.">Effects of recombinant dimeric TNF receptor on human inflammatory responses following intravenous endotoxin administration.</a> J Immunol. 155, 5038-5045 (1995).</li><li>Fink, M. P. <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.">Animal models of sepsis.</a> Virulence. 5, 143-153 (2014).</li><li>Poltorak, 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=Defective+LPS+signaling+in+C3H/HeJ+and+C57BL/10ScCr+mice:+mutations+in+Tlr4+gene.">Defective LPS signaling in C3H/HeJ and C57BL/10ScCr mice: mutations in Tlr4 gene.</a> Science. 282, 2085-2088 (1998).</li><li>Hoshino, K., 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=Cutting+edge:+Toll-like+receptor+4+(TLR4)-deficient+mice+are+hyporesponsive+to+lipopolysaccharide:+evidence+for+TLR4+as+the+Lps+gene+product.">Cutting edge: Toll-like receptor 4 (TLR4)-deficient mice are hyporesponsive to lipopolysaccharide: evidence for TLR4 as the Lps gene product.</a> J Immunol. 162, 3749-3752 (1999).</li><li>Corral, J., 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=Role+of+lipopolysaccharide+and+cecal+ligation+and+puncture+on+blood+coagulation+and+inflammation+in+sensitive+and+resistant+mice+models.">Role of lipopolysaccharide and cecal ligation and puncture on blood coagulation and inflammation in sensitive and resistant mice models.</a> Am J Pathol. 166, 1089-1098 (2005).</li><li>Shrum, 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=A+robust+scoring+system+to+evaluate+sepsis+severity+in+an+animal+model.">A robust scoring system to evaluate sepsis severity in an animal model.</a> BMC Res Notes. 7, 233 (2014).</li><li>Brandwein, S. 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=Spontaneously+colitic+C3H/HeJBir+mice+demonstrate+selective+antibody+reactivity+to+antigens+of+the+enteric+bacterial+flora.">Spontaneously colitic C3H/HeJBir mice demonstrate selective antibody reactivity to antigens of the enteric bacterial flora.</a> J Immunol. 159, 44-52 (1997).</li><li>Macpherson, A. J., McCoy, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standardised+animal+models+of+host+microbial+mutualism.">Standardised animal models of host microbial mutualism.</a> Mucosal Immunol. 8, 476-486 (2015).</li><li>Masopust, D., Sivula, C. P., Jameson, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Of+Mice,+Dirty+Mice,+and+Men:+Using+Mice+To+Understand+Human+Immunology.">Of Mice, Dirty Mice, and Men: Using Mice To Understand Human Immunology.</a> J Immunol. 199, 383-388 (2017).</li><li>Wirtz, S., 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=Protection+from+lethal+septic+peritonitis+by+neutralizing+the+biological+function+of+interleukin+27.">Protection from lethal septic peritonitis by neutralizing the biological function of interleukin 27.</a> J Exp Med. 203, 1875-1881 (2006).</li></ol>

This protocol mimics immunological processes that occur after the invasion by microbial-derived products. Critical steps within the protocol are the selection of the mouse line, the hygiene status of the mice, the dose of LPS, the monitoring of the animals for the occurrence of endotoxemia, and the time point of experiment termination. Most importantly, the genetic background of the mouse strain has to be considered. Different mouse strains have different susceptibility to LPS. For example, the C3H/HeJ and C57BL/10ScCr m...

The human intestine is colonized with a large consortium of microorganisms that forms the microbiota, who has developed a mutually beneficial relationship with the host during the evolution. In this relationship, the host provides a secure niche for the microbiota, whereas the microbiota provides vitamins, nutrient digestion and protection from pathogens to the host, where the microbiota resides1. When this beneficial relationship between the host and the microbiota is disturbed, diseases can develop, such as inflammatory bowel disease (IBD). IBD is a multifactorial chronic inflammatory disease of the intestine caused by genetic and environmental factors that occur in two major forms, Crohn&#39;s disease (CD) and ulcerative colitis (UC). Despite similarities between the two IBD forms, they are characterized by certain differences in the location and nature of inflammatory modifications. CD is a relapsing transmural inflammatory disorder that can potentially extend to any part of the gastrointestinal tract, while UC is non-transmural and is restricted to the colon. Furthermore, mutations in Nucleotide-binding oligomerization domain-containing protein 2 (NOD2), a pattern recognition receptor (PRR) that recognizes muramyl dipeptide (MDP), a component of the cell wall of most Gram-positive and - negative bacteria, is associated with CD2. Furthermore, Escherichia coli (E. coli), Listeria and Streptococci and their products were all found within macrophages in CD patients that have entered the host after a barrier breach3. When bacteria or their products enter the host during the development of CD, the immune system develops a response leading to the production of circulating anti-bacterial antibodies4. Maybe, the most convincing evidence for the role of the microbiota in the pathogenesis of IBD stems from mouse models. When animals are treated with antibiotics, or when mice are kept in germ-free (GF) conditions, the severity of the disease is reduced in most colitis models, such as in IL-10-/- mice that do not develop colitis in GF facilities5,6. Furthermore, colitis also disturbs the composition of the microbiota, which is characterized by an imbalanced composition and reduced richness called dysbiosis7. The consequence of IBD can be an increased intestinal permeability that can lead to the entrance of microbes and microbial-derived products into the host.
In animals, the application of Dextran Sodium Sulfate (DSS) induces an intestinal epithelial breach leading to an increased permeability of the epithelial barrier8. Portal LPS concentrations are elevated in animals with DSS colitis9. Interestingly, animals lacking the C type lectin receptor specific intracellular adhesion molecule-3 grabbing nonintegrin homolog-related 1 (SIGN-R1) are protected from DSS colitis and LPS-induced endotoxemia10. To further disseminate into the host, bacteria or bacteria derived products have to pass the vascular barrier11, the peritoneal cavity, in which the small and large intestine is located, the mesenteric lymph nodes and/or the liver12. To reduce the complexity of this system, a defined bacterial-derived compound was used. LPS, which causes endotoxemia after intraperitoneal (i.p.) or intravenous (i.v.) injection13 was injected into mice, to study the expression of the interleukins Il6 and Ilb and the cytokine Tnfa in response to LPS.
LPS is a pathogen-associated molecular pattern (PAMP) expressed as a cell-wall component of Gram-negative bacteria, that consists of lipid A (the main PAMP in the structure of LPS), a core oligosaccharide and an O side chain14. Toll-like receptor 4 (TLR4) expressed by dendritic cells, macrophages, and epithelial cells recognizes LPS15, that requires co-receptors for appropriate binding. The acute phase protein LPS-binding protein (LBP) binds LPS to form a complex that transfers LPS to the cluster of differentiation 14 (CD14), a glycosylphosphatidylinositol-anchored membrane protein. CD14 further shuttles LPS to Lymphocyte antigen 96 or also known as MD-2, which is associated with the extracellular domain of TLR4. The binding of LPS to MD-2 facilitates the dimerization of TLR4/MD-2 to induce conformational changes to recruit intracellular adaptor molecules to activate the downstream signaling pathway14, which includes the myeloid differentiation primary response gene 88 (MyD88)-dependent pathway and the TIR domain-containing adaptor-inducing interferon-&#946; (TRIF)-dependent pathway16. The recognition of LPS by TLR4 then activates the NF-&#954;B pathway and induces the expression of proinflammatory cytokines, such as TNF&#945;, IL-6, and IL-1&#946;17.
In particular, when LPS is injected into animals, the concentration of LPS given to the animals, the genetic background of the animal and the diet has to be considered. High concentrations of LPS leads to a septic shock, characterized by hypotension and multiple organ failures, and finally to death18. Mice are less sensitive to LPS compared to humans, where LPS concentrations between 2-4 ng/kg body weight (BW) are able to induce a cytokine storm19. For mice, the lethal dose (LD50), which induces death in half of the mice ranges from 10-25 mg/kg BW20 depending on the mouse strain used. For the commonly used mouse strains, C57Bl/6 and BALB/c, the lethal dose 50% (LD50) is 10 mg/kg BW. In contrast, the strains C3H/HeJ and C57BL/10ScCr are protected from LPS induced endotoxemia, which is due to mutations in Tlr421. Consequently, Tlr4-deficient mice are hyporesponsive to injections with LPS22. Other genetically modified mouse lines, such as PARP1-/- mice23 are resistant to LPS-induced toxic shock.
The mouse model described here uses a sublethal dose of LPS administered systemically to mimic the consequences of LPS dissemination after a barrier breach of the body`s surfaces. The chosen LPS concentration (2 mg/kg BW) did not induce mortality in C56Bl/6 mice, but the induced release of pro-inflammatory cytokines.

<table border="0" cellpadding="0" cellspacing="0" width="896">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:307px;">DreamTaq Green PCR Master Mix (2x)</td>
			<td style="width:303px;">Thermo Fisher Scientific, Waltham, MA, USA</td>
			<td style="width:119px;">K1081</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">High Capacity cDNA Reverse Transcription Kit,</td>
			<td style="width:303px;">Applied Biosystems, Foster City, CA, USA</td>
			<td>4368813</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RNase-Free DNase Set,</td>
			<td>Qiagen, Hilden, Germany</td>
			<td>79254</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LPS Escherichia coli O111:B4</td>
			<td>Invivogen, San Diego, CA, USA.</td>
			<td>tlrl-eblps</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Omnican 50 Single-use insulin syringe</td>
			<td>B. Braun Melsungen, Melsungen, Germany</td>
			<td>9151125</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bioanalyzer 2100</td>
			<td>Agilent Technologie, Santa Clara, USA</td>
			<td style="width:119px;">not applicable</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Centrifuge 5430</td>
			<td>Eppendorf, Hamburg, Germany</td>
			<td style="width:119px;">not applicable</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Centrifuge Mikro 220R</td>
			<td>Hettich, Kirchlengern, Germany</td>
			<td style="width:119px;">not applicable</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dissection tools</td>
			<td>Aesculap, Tuttlingen, Germany</td>
			<td style="width:119px;">not applicable</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fast-Prep-24 5G Sample Preparation System</td>
			<td>M.P. Biomedicals, Santa Ana, CA, USA</td>
			<td style="width:119px;">not applicable</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NanoDrop ND-1000</td>
			<td>NanoDrop Products, Wilmington, DE, USA</td>
			<td style="width:119px;">not applicable</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TRI Reagent</td>
			<td>Zymo Research, Irvine, CA, USA</td>
			<td>R2050-1</td>
			<td></td>
		</tr>
	</tbody>
</table>

injections of lipopolysaccharide into mice to mimic entrance of microbial-derived products after intestinal barrier breach

The intestinal epithelial barrier separates the host from the microbiota that is normally tolerated or ignored. The breach of this barrier results in the entrance of bacteria or bacteria-derived products into the host, accessing the host circulation and inner organs leading to the uncontrolled inflammation as observed in patients with inflammatory bowel disease (IBD), that are characterized by an increased intestinal epithelial permeability.
To mimic the entrance of bacterial-derived compounds into the host, an endotoxemia model has been adopted in which lipopolysaccharide (LPS), a component of the outer cell wall of Gram-negative bacteria, were injected into mice. In this study, a sublethal dose of LPS was intraperitoneally injected and the mice were subsequently monitored for 8 h using a disease score. Furthermore, the expression levels of the inflammatory cytokines Il6, Il1b, and Tnfa were analyzed in the spleen, liver and colon by qPCR at different time points post LPS injection. This model could be useful for the studies involving investigation of immune responses after the invasion of microorganisms or bacterial-derived products caused by a barrier breach of body surfaces.

To mimic the consequences for the host after the entrance of bacteria or bacterial-derived products that occurs after intestinal barrier breach, LPS was injected into C57Bl/6 mice in a sublethal dose (2 &#181;g/g body weight). Every single mouse was monitored and scored for the occurrence of endotoxemia with parameters listed in score sheet that includes, the appearance of the mice, the activity of the animals, the condition of eyes, and the respiration rate and quality (Table 1</...

Watch this Scientific Journal Video about Injections of Lipopolysaccharide into Mice to Mimic Entrance of Microbial-derived Products After Intestinal Barrier Breach at JoVE.com

Injections of Lipopolysaccharide into Mice to Mimic Entrance of Microbial-derived Products After Intestinal Barrier Breach

Here a protocol to mimic the entrance of bacterial-derived compounds after intestinal barrier breach is presented. A low sublethal dose of lipopolysaccharide was injected systemically into mice, which were monitored for 24 h post-injection. The expression of pro-inflammatory cytokines was determined at several time points in spleen, liver, and colon.

The intestinal epithelial barrier separates the host from the microbiota that is normally tolerated or ignored. The breach of this barrier results in the ...

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