Intraperitoneal E.coli–Induced Sepsis: A Preliminary Study of Rat Model

Sepsis remains a complex clinical challenge, with experimental animal models being crucial for developing effective therapeutic strategies. Current approaches often struggle to establish clinically relevant animal models that accurately represent human sepsis pathogenesis. This study aimed to determine the optimal intraperitoneal Escherichia coli (E. coli) dose for inducing a reproducible sepsis state in male rats. A preliminary experimental study was conducted using male Rattus norvegicus rats divided into three groups: a control group and two sepsis groups induced with E. coli at doses of ۱×۱۰۶ and ۱.۵×۱۰۶ CFU/kg. Biomarkers including neutrophils, procalcitonin (PCT), interleukin-۶ (IL-۶), and malondialdehyde (MDA) were measured at ۲۴-, ۴۸-, and ۷۲-hours post-induction. Histopathological examinations of liver, kidney, spleen, and heart tissues were performed using hematoxylin and eosin staining. Both E. coli doses significantly increased inflammatory and infection biomarkers. Dose of ۱.۵×۱۰۶ CFU/kg demonstrated higher biomarker levels and more severe organ damage compared to control group and ۱×۱۰۶ CFU/kg dose. In dose of ۱.۵×۱۰۶ CFU/kg group, Neutrophil levels increased from baseline ۱.۴×۱۰۳ to ۷.۷۱×۱۰۳ mmol/dL, IL-۶ from ۲۰.۷۲ to ۷۷.۴۹ pg/mL, MDA from ۱.۳۷ to ۱۲.۱۵ nmol/mL and PCT from a normal level of ۳.۱ to ۵.۷۹ ng/mL within ۷۲ hours, meeting the criteria for sepsis. Histopathological examination revealed significant organ damage, with higher induction doses correlating with increased histopathological damage scores. Intraperitoneal E. coli induction at ۱.۵×۱۰۶ CFU/kg effectively creates a reproducible sepsis model in rats, providing a valuable experimental approach for studying sepsis pathogenesis and potential interventions.

Keywords:

Sepsis , E. coli , rat model , inflammatory biomarkers , Organ Damage