All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.<ol><li>Intraperitoneal Injection of lipopolysaccharide (LPS) to Mice<ol style='list-style-type:decimal;'><li>Aspirate the LPS working solution in a 0.5 mL syringe with a 30 G needle in a laminar air flow.</li><li>Weigh female C57Bl/6 mice (six to 10 weeks of age) and calculate the amount of LPS that will be injected: 10 &#181;L (2 &#181;g)/g body weight. NOTE: For example, if a mouse weighs 20 g, then 20 g x 10 &#181;L = 200 &#181;L LPS working solution needs to be injected.</li><li>Handle the mouse gently but firmly and restrain the animal in one hand. Ensure that the animal is able to breathe normally but not to twist and turn during the restraint.</li><li>Tilt the mouse nose slightly towards the floor to expose the abdomen for injection. Locate the midline of the abdomen and the injection place in the low abdomen left or right from the midline. Inject intraperitoneally (i.p.) phosphate-buffered saline (PBS) instead of LPS into control mice.</li><li>With the free hand, inject the appropriate volume (the volume calculated in step 1.2) of the LPS working solution. Make sure that the needle has entered the peritoneal cavity as otherwise, mis-injections into the abdominal muscle layer may occur. Still, do not go too deep with the needle into the peritoneal cavity to avoid injuring inner organs located in that area.</li><li>Return the animal carefully to the cage with up to 5 mice per cage.</li></ol></li></ol>

<table class='ck-table-resized'><tbody><tr><td>LPS Escherichia coli O111:B4</td><td>Invivogen, San Diego, CA, USA.</td><td>tlrl-eblps</td><td>&#160;</td></tr><tr><td>Omnican 50 Single-use insulin syringe</td><td>B. Braun Melsungen, Melsungen, Germany</td><td>9151125</td><td>&#160;</td></tr></tbody></table>

intraperitoneal injection of bacterial lipopolysaccharide in mice to study systemic immune responses

Source: <a href='https://app.jove.com/v/57610/injections-lipopolysaccharide-into-mice-to-mimic-entrance-microbial'>Radulovic, K., et al. Injections of Lipopolysaccharide into Mice to Mimic Entrance of Microbial-derived Products After Intestinal Barrier Breach. J. Vis. Exp. (2018)</a>This video demonstrates a step-by-step procedure for injecting lipopolysaccharide (LPS) into mice intraperitoneally to induce systemic inflammation.

Intraperitoneal Injection of Bacterial Lipopolysaccharide in Mice to Study Systemic Immune Responses

Source: Radulovic, K., et al. Injections of Lipopolysaccharide into Mice to Mimic Entrance of Microbial-derived Products After Intestinal Barrier Breach. ...

Begin with an awake mouse, restrained to limit its movement.Tilt the head downward to expose the lower abdomen.Locate the abdominal midline and identify an injection site slightly off-center to avoid internal organs.Next, take a syringe containing a solution of lipopolysaccharides, a component of Gram-negative bacterial cell envelope.Insert the needle into the site to access the peritoneal cavity, and inject the solution.Once injected, LPS enters systemic circulation and triggers an immune response.In the bloodstream, LPS binds to LPS-binding protein, which transfers it to CD14, a membrane protein on immune cells.CD14 delivers LPS to MD-2, a glycoprotein that associates with Toll-like receptor 4 (TLR4), enabling TLR4 dimerization.Dimerized TLR4 recruits adaptor proteins that activate downstream signaling pathways, inducing proinflammatory cytokine expression and systemic inflammation.This models microbial translocation and systemic immune activation in the intestines and other organs caused by bacterial products.Handle the mouse gently but firmly, and restrain the animal in one hand. Ensure that the mouse is securely held and can breathe normally.Tilt the mouse nose slightly towards the floor to expose the abdomen for injection. Locate the midline of the abdomen and inject the volume of LPS required on the lower-left or right side.It is very important to ensure that the needle enters the peritoneal cavity to avoid misinjections.The needle should also not go too deep into the peritoneal cavity to avoid injury of inner organs.Gently return the animal to the home cage.Monitor the mice for the occurrence and severity of endotoxemia at the time of injection and every 2 hours thereafter for 8 hours. Record observations in the attached score sheet.

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518 Views. Begin with an awake mouse, restrained to limit its movement.Tilt the head downward to expose the lower abdomen.Locate the abdominal midline and identify an injection site slightly off-center to avoid internal organs.Next, take a syringe containing a solution of lipopolysaccharides, a component of Gram-negative bacterial cell envelope.Insert the needle into the site to access the peritoneal cavity, and inject the solution.Once injected, LPS enters systemic ci...

Intraperitoneal Injection of Bacterial Lipopolysaccharide in Mice to Study Systemic Immune Responses

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