Therapeutic potential of heat-killed Lactobacillus reuteri against bile acid-induced male reproductive toxicity.

Exposure of testicular tissue to supraphysiological concentrations of bile acids can lead to infertility. This study aimed to investigate the protective effects of heat-killed Lactobacillus reuteri (L. reuteri) against male reproductive toxicity induced by bile duct ligation (BDL). Thirty-two male Wistar rats were randomly assigned to four groups (N = 8): control normal (CN), sham-control (SC), BDL-control (underwent BDL surgery), and BDL + heat-killed L. reuteri (received probiotic supplementation for 7 days before and 21 days after BDL). At the end of the study, reproductive parameters, including sex hormones, sperm characteristics, oxidative stress markers, antioxidant status, and inflammatory gene expression in testicular tissue, were analyzed. Additionally, histological assessments of the testis and epididymis were performed. The administration of heat-killed L. reuteri significantly improved sperm viability (p ≤ 0.05) and luteinizing hormone levels (p ≤ 0.05) while reducing total oxidative status, carbonyl protein, and oxidative stress index (p ≤ 0.05) compared to the BDL-control group. Moreover, nitric oxide levels were significantly increased (p ≤ 0.05) in the probiotic-treated group. The expression levels of TNF-α and IL-6 were notably downregulated (p ≤ 0.05), indicating reduced testicular inflammation. Histological analysis demonstrated significant improvements in epithelial height, spermatogenic epithelial area ratio, lumen diameter, and lumen area (p ≤ 0.05) in the probiotic-treated group. These findings suggest that heat-killed L. reuteri alleviates cholestasis-related male reproductive toxicity through its antioxidant and anti-inflammatory effects.