Bifidobacterium longum subsp. infantis NKU FB3-14 attenuates loperamide-induced constipation through regulation of gut microbiota

Abstract Objectives Constipation is a prevalent gastrointestinal issue, and the efficacy of probiotics in alleviating constipation has been well proved. This study aimed to investigate the impact of Bifidobacterium longum subsp. infantis NKU FB3-14 on loperamide- induced constipation by focusing on improving intestinal barrier function and modulating gut microbiota composition Materials and Methods The constipated model mice induced by loperamide were treated with NKU FB3-14, and the laxative effect was assessed based on the fecal water content, first black stool time and gastrointestinal transit rate. Gastrointestinal regulatory peptides in serum, intestinal neurotransmitter and inflammatory cytokines in colon tissues were measured using ELISA kits. Changes of gut microbiota composition were analyzed through 16S ribosomal DNA sequencing identification. Additionally, HPLC detection was performed to quantify short chain fatty acids levels in feces Results Treatment with NKU FB3-14 led to increase the fecal water content, shorten the first black stool time and improve small intestine transit rate. Motilin and substance-P significantly decreased in the model group, and only motilin increased in FB3-14 group; somatostatin and vasoactive intestinal peptide were decreased in model mice and both increased in FB3-14 group; 5-HT levels in the colon tissue were upregulated following NKU FB3-14 treatment. Histological examination revealed thinner colonic mucosa in the model group along with significant in TNF-α, IL-1β and IL-17 levels form the colon tissues which were all relieved by NKU FB 3-14 treatment. Furthermore, NKU FB3-14 intervention resulted in reduced abundance of Desulfobacterota and Desulfovibrio while increasing the abundance of Ruminococcaceae and Eubacterium; higher level of butyric acid was observed in feces Conclusions In summary, our findings demonstrated that NKU FB3-14 treatment significantly enhanced the intestinal motility, regulated the expression levels of gastrointestinal regulatory peptides, prevented damage to colonic barriers as well as ameliorated gut microbiota imbalance associated with loperamide-induced constipation.