protective effects of encapsulated bacillus subtilis on oxidative stress, spermatogenesis, and fertility outcomes in experimental cholestasis

Objective: probiotics such as bacillus subtilis exhibit antioxidant and anti-inflammatory activities. however, their viability may be reduced in the gastrointestinal tract (git) due to acidity and enzymatic degradation. encapsulation can improve probiotic survival and bioactivity. probiotics have also been implicated in mitigating oxidative stress–induced reproductive toxicity. this study evaluated the effects of encapsulated b. subtilis on oxidative balance, sperm quality, and testicular histology in an experimental model of liver cholestasis. methods: forty-eight male wistar rats were randomly assigned to four groups: control, probiotic, free capsule, and encapsulated probiotic. encapsulated b. subtilis (3 × 109 cfu/day) was administered orally for one week prior to bile duct ligation (bdl) and for three weeks afterward. at the end of the experiment, rats were euthanized, and blood and testes were collected for biochemical, hormonal, and histological analyses. results: bdl markedly reduced sperm concentration and viability while increasing morphological abnormalities. encapsulated b. subtilis significantly improved sperm parameters compared to free probiotics. testicular oxidative stress, evidenced by increased protein carbonyls and total oxidant status with decreased reduced glutathione, was attenuated by encapsulated probiotics. histological analysis revealed disrupted testicular architecture and decreased johnson's scores after bdl, whereas encapsulated b. subtilis restored seminiferous tubule integrity and spermatogenesis. conclusion: encapsulated b. subtilis enhanced probiotic efficacy, improving sperm quality, antioxidant status, and testicular structure in cholestatic rats. these findings suggest a protective role for encapsulated probiotics in male infertility associated with oxidative stress and liver disease.