Abstract
Diarrheal disease caused by Escherichia coli is a major cause of disease worldwide. The mutations that bacteria undergo lead to antibiotic resistance, necessitating the development of evidence-based treatment alternatives. This research investigates the immunomodulatory effects of Lactobacillus acidophilus as a probiotic and pomegranate peel aqueous extract (PPE) from the pomegranate plant (Punica granatum L.), individually and in combination, on certain innate and adaptive immunity markers in experimentally infected BALB/c mice with E. coli-induced diarrhea. 40 male BALB/c mice (6–8 weeks old, weighing 20–25 g) were randomly assigned to five groups (8 mice per group): negative control (G1), positive control infected with E. coli only (G2), E. coli with Lactobacillus acidophilus (109 CFU/day) (G3), E. coli with pomegranate peel extract (200 mg/kg/day) (G4), and E.coli with the Mix therapy (G5). All treatments were administered orally for 21 days. The concentrations of cytokines (IL-6, TNF-α, IFN-γ, IL-10), immunoglobulins (IgG, IgM, IgA), splenic lymphocyte subsets (CD4+, CD8+, and natural killer cells), and the phagocytic index of phagocytes were measured at the end of the experiment. A significant decrease in the levels of the pro-inflammatory cytokines IL-6, TNF-α, and IFN-γ was observed in group G5 compared to group G2 (p ≤ 0.05), while IL-10 did not show a statistically significant difference between the two groups. Serum IgG and CD4+ T cell levels returned to normal significantly in group G5 (p ≤ 0.05), while IgM, IgA, CD8+ T cell levels, the CD4+/CD8+ ratio, and the frequency of natural killer cells remained largely unchanged. The phagocytosis index was also significantly higher in group G5 compared to group G2 (p ≤ 0.05). The synergistic action of L. acidophilus and the aqueous PPE extract demonstrated statistically significant immunomodulatory activity, suggesting its potential as an alternative treatment in the management of E. coli-induced diarrhea.