Lactobacillus johnsonii JJB3 Ameliorates Oxidative Stress-Induced Intestinal Injury and Mitochondrial Damage by Promoting BNIP3L-Mediated Mitophagy.

The intestine is particularly susceptible to oxidative damage given its extensive exposure to environmental toxins, dietary components, and microbial metabolites, which leads to various gastrointestinal and systemic diseases. There is an urgent need for effective and safe therapies to maintain intestinal redox balance. This study aimed to explore whether the pig-native strain Lactobacillus johnsonii JJB3, known for its potential in mitigating oxidative stress, can prevent intestinal oxidative stress and elucidate its underlying mechanisms. Our study found that L. johnsonii JJB3 supernatant (sJJB3) effectively ameliorated hydrogen peroxide (HO)-induced oxidative stress in intestinal porcine epithelial cell line-J2 (IPEC-J2), manifested by reduced levels of reactive oxygen species (ROS) and increased levels of catalase and glutathione. RNA sequencing revealed that the mitophagy pathway plays a crucial role in this protective effect. Specifically, sJJB3 treatment further enhanced HO-induced upregulation of BNIP3L and LC3B at both mRNA and protein levels, promoting mitophagy. These findings were validated in a mouse model of diquat (DQ)-induced intestinal oxidative stress. sJJB3 supplementation reversed DQ-induced oxidative damage, especially in the jejunum, and increased BNIP3L and LC3B expression. Transmission electron microscopy further confirmed that sJJB3 preserved mitochondrial ultrastructure and supported effective mitophagy. Additionally, 16S rRNA sequencing showed that sJJB3 improved gut microbiota composition. These results provide a new theoretical foundation for the application of sJJB3 in mitigating oxidative stress-related intestinal injury.