Alleviating effect and mechanism of Lactobacillus helveticus ZJUIDS18 on colitis induced by DSS in mice

Inflammatory bowel disease (IBD) is a prevalent intestinal disorder that profoundly affects human and animal health. Emerging evidence highlights the therapeutic potential of lactic acid bacteria (LAB) in mitigating gastrointestinal pathologies. Prior studies have shown that Lactobacillus helveticus ZJUIDS18 exhibits favorable in vitro growth characteristics, and has the potential to alleviate colitis. This study aimed to investigate the therapeutic effect and mechanism of L. helveticus ZJUIDS18 on mice colitis induced by sodium dextran sulfate (DSS). Key findings demonstrated that L. helveticus ZJUIDS18 intervention can effectively alleviate the symptoms of colitis induced by DSS in mice, including inhibiting the weight loss, colon shortening, and reducing disease activity index score as well as colonic tissue lesions. It increased the expression of tight junction proteins (ZO-1, claudin-1, and occludin) and mucin (MUC2) in colon tissue and decreased the level of myeloperoxidase (MPO), malondialdehyde (MDA), and pro-inflammatory factors IL-6 in colon tissue. Moreover, L. helveticus ZJUIDS18 intervention restored intestinal dysbiosis by down-regulating the relative abundance of harmful genera, namely Parabacteroides, Escherichia-Shigella, and Bacteroides and up-regulating the relative abundance of Bifidobacterium and Erysipelotrichaceae_uncultured. It also significantly increased the content of short-chain fatty acids, including acetic acid and propionic acid. Metabolic profiling further identified the tryptophan metabolism pathway as a critical mediator of the strain's anti-inflammatory effects, with L. helveticus ZJUIDS18 effectively ameliorating DSS-induced metabolic dysregulation. In summary, L. helveticus ZJUIDS18 could be as a probiotic candidate for developing targeted therapeutic strategies against IBD.