Impact d’un probiotique sur la réponse biochimique à l’inflammation chez la souris Balb/c

Abstract

Exposure to Escherichia coli induces intestinal inflammation associated with oxidative stress, gut microbiota dysbiosis, and impairment of the intestinal barrier. Lactobacilli exert a protective effect by modulating the immune response, reducing pro-inflammatory cytokines and free radicals, and promoting the maintenance of intestinal homeostasis. The present study aims to investigate the effects of exposure to Escherichia coli on inflammation, oxidative stress, and intestinal dysbiosis in mice, as well as to evaluate the protective effect of Lactobacillus through its immunomodulatory and anti-inflammatory activity. 18 Balb/c mice aged 3 to 4 weeks were divided into 3 groups of 6 mice each, comprising an equal number of males and females. The experimental groups consisted of a control group (naive mice), an inflamed group (receiving sterile saline solution for 14 days, followed by two intraperitoneal injections of E. coli at 10⁶ CFU/mL spaced 24 hours apart), and a treated group (receiving the same bacterial strain after a 14-day pretreatment with Lactobacillus sp. at 10⁸ CFU/mL via intragastric route). The impact of inflammation and the preventive effect of the probiotic were assessed through analysis of intestinal morphological changes, hematological and biochemical parameters, oxidative stress (TBARS assay), and clinical signs of inflammation. The main results obtained show that exposure to E. coli induces a systemic inflammatory response, characterized by alterations in clinical, hematological, and biochemical parameters, as well as a disruption of redox homeostasis. In contrast, pretreatment with Lactobacillus sp. significantly improved the body weight of mice compared to the control and inflamed groups (p<0.001), and significantly reduced C-reactive protein (CRP) levels, indicating a pronounced anti-inflammatory effect. Furthermore, a significant elevation in TBARS, a marker of lipid peroxidation, was observed only in inflamed females. Overall, these findings indicate that Lactobacillus sp. appears to be capable of favorably modulating the immune response, limiting lipid peroxidation, and preserving the functional integrity of the host against bacterial challenge.