Creating a Septic Shock Model in Adult Wistar Rats and Observing the Effect of Noradrenaline

Sajo, Thomas (2020) Creating a Septic Shock Model in Adult Wistar Rats and Observing the Effect of Noradrenaline. Masters thesis, Christian Medical College, Vellore.


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BACKGROUND: septic shock experiments usually use lipopolysaccharides (endotoxemia model) or polymicrobial model (using caecal ligation or puncture methods), while researchers rarely use live bacterial injections. Our broader aim is to create animal models of septic shock using different strains of live bacteria to understand sepsis pathophysiology better. AIM OF THE STUDY: 1. Creation of a rat model of septic shock using live strains of Escherichia coli and studying the various cardiovascular parameters. 2. To study the effect of administering Noradrenaline (a sympathomimetic drug). METHODS: After random selection, we anesthetized the Wistar rats (WR) for Intra-arterial pressure recordings from the carotid artery using ADInstruments® data acquisition device. Live E-Coli suspended in normal saline (5Mcfarland concentration; dose - 650uL/100gram) was injected through the tail vein to induce sepsis and observed for the development of shock (i.e., a drop in mean arterial pressure (MAP) of 50% from the initial MAP). The first group (n=7), consisted of the addition of E.coli alone, whereas the second group (n=7), comprised of rats treated with Noradrenaline. A negative control group (n=4), was also included in the study. The recordings were analyzed using a customized Matlab® code written by us. RESULTS: 75% rats (n=14, Group 1 & 2) had a pressure drop in about 2.5 hours (max – 4.2 hrs & min – 0.6hrs) after the addition of E.coli and 75% rats (n=7, group 1) died within 57 minutes (max – 62.3 minutes & min – 9.9 minutes) without any intervention. Addition of noradrenaline subsequent to pressure drop after Ecoli, in 7 rats (group 2) prolonged the time to death significantly to about 170 minutes (max - 496.04 minutes & min - 104.47minutes). CONCLUSION: 1. The above rat model of E.coli septic shock is useful to study various aspects of septic shock. 2. Noradrenaline prolonged the life of the animal in septic shock. 3. The above model paves the way for sepsis studies due to other common agents of sepsis encountered in clinics.

Item Type: Thesis (Masters)
Additional Information: 201715353
Uncontrolled Keywords: Septic shock, Animal model, Escherichia coli, Noradrenaline.
Subjects: MEDICAL > Physiology
Depositing User: Subramani R
Date Deposited: 30 Jan 2021 17:17
Last Modified: 01 Mar 2021 02:30

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