Bacillus subtilis attenuates acetaminophen-induced liver injury and preserves gut–liver homeostasis in mice

Abstract

Abstract Acetaminophen (APAP) overdose produces an early oxidative insult followed by sterile inflammation and tissue repair, but whether probiotic interventions can influence these distinct phases remains unclear. Here, we evaluated the effects of Bacillus subtilis on APAP-induced liver injury in mice. B. subtilis pretreatment reduced serum aminotransferases and hepatic necrosis, restored the hepatic GSH/GSSG ratio, and decreased cellular ROS and p-JNK level at 24 h. When B. subtilis treatment was initiated after APAP and continued daily, it did not significantly reduce liver injury at 48 h but lowered serum aminotransferases and residual hepatic necrosis at days 5 and 7, consistent with a later recovery-associated benefit. B. subtilis pretreatment reduced the frequencies of Ly-6G⁺ neutrophils and total myeloid cells during acute injury, increased the proportion of TIM4⁺ Kupffer cells during recovery, and shifted serum cytokines toward a less inflammatory profile. In parallel, B. subtilis preserved colonic morphology and occludin/ZO-1 expression and lowered circulating LPS. Recovery-stage transcriptomic and microbiome analyses associated B. subtilis with antioxidant and metabolic programs and altered microbial community structure. Metabolomic analysis identified candidate metabolites elevated in B. subtilis -treated mice; among these, histidine and acetyl-L-carnitine were selected for functional testing and provided partial biochemical protection, whereas only live B. subtilis reproduced the combined hepatic and intestinal effects. These findings show that viable B. subtilis limits acute APAP hepatotoxicity and supports recovery while preserving intestinal barrier integrity.