Bifidobacterium animalis Subsp. lactis PB200 Improves Intestinal Barrier Function and Flora Disturbance in Mice with Antibiotic-Induced Intestinal Injury

<b>Background/Objectives</b>: Overuse or misuse of antibiotics could cause adverse effects such as gut microbiota dysbiosis and intestinal barrier dysfunction. Probiotic intervention could effectively alleviate these symptoms. However, the precise efficacy of <i>Bifidobacterium animalis</i> subsp. <i>lactis</i> PB200 (<i>B. lactis</i> PB200) in mitigating antibiotic-induced intestinal injury remains unclear. <b>Objective:</b> The aim of this study was to systematically evaluate the effects of <i>B. lactis</i> PB200 on intestinal barrier injury and gut microbiota dysbiosis in a murine model of antibiotic-induced intestinal injury. <b>Methods:</b> BALB/c mice were administered ceftriaxone sodium via oral gavage for seven consecutive days, followed by probiotic intervention daily via gastric gavage for 4 weeks. <b>Results:</b> The results indicated that <i>B. lactis</i> PB200 played a positive role in enhancing intestinal barrier function, as evidenced by the restored intestinal morphology, and elevated the expression of tight junctions including ZO-1, Claudin-4 and Occludin (2.76-fold, 4.39-fold, and 2.61-fold, respectively) compared to that in the Model group. <i>B. lactis</i> PB200 normalized the levels of serum pro- and anti-inflammatory factors, including IL-1β, IL-6, TNF-α and IL-10, and elevated the diversity and richness of gut microbiota. <i>B. lactis</i> PB200 significantly elevated the levels of propionic acid and butyric acid, with increases of 1.67-fold and 2.82-fold, respectively, compared to the Model group. Notably, <i>B. lactis</i> PB200 reduced the abundance of <i>Enterocloster</i> and increased the abundance of <i>Parabacteroides</i>, promoting the rebalance of gut microbiota. <b>Conclusions:</b> Taken together, these findings highlighted the significant potential of <i>B. lactis</i> PB200 in alleviating intestinal barrier damage and restoring the balance of gut microbiota caused by an antibiotic.