Highly Active Probiotic Yogurt Protects Against Cyclophosphamide-Induced Immunosuppression in Mice by Regulating Immune Response and gut microbiota

Probiotics play a crucial role in modulating the immune system and maintaining the integrity of intestinal epithelial barrier. The study investigates the effects of high-activity probiotic yogurt on immunosuppressed mice induced by cyclophosphamide. On days 7, 8, and 9 of the experiment, ICR male mice (eight-week-old) were injected intraperitoneally with cyclophosphamide (80 mg/kg body weight/day) to establish an immunosuppressive model (n = 10). Mice fed with normal diet or high-activity probiotic yogurt for consecutive 14 days. The effect of high-activity probiotic yogurt on immunosuppressed mice was investigated by HE staining, enzyme-linked immunosorbent assay (ELISA), Western blotting, and 16s rRNA assay. Results indicated that after the treatment of high-activity probiotic yogurt, the immune organ indices, interleukin-6(IL-6), interleukin-12(IL-12), tumor necrosis factor-α (TNF-α), and intestinal structure are significantly increased in immunosuppressed mice (P < 0.05). Western blotting analysis find that high-activity probiotic yogurt improves the expression of toll-like receptor 4 (TLR4), nuclear factor kappa-B –p65(p65), TNF receptor associated factor 6(TRAF6). Furthermore, microbiota analysis showed that high-activity probiotic yogurt significantly increased the diversity and richness of the gut microbiota(P < 0.05). These findings indicated that high-activity probiotic yogurt may improve the immune function of mice by improve intestinal homeostasis and activation of TLR pathway.