Lactobacillus kefiranofaciensJKSP109 andSaccharomyces cerevisiaeJKSP39 isolated from Tibetan kefir grain co-alleviated AOM/DSS induced inflammation and colorectal carcinogenesis

This study aimed to investigate the alleviative effects of Lactobacillus kefiranofaciens JKSP109 (LK) and Saccharomyces cerevisiae JKSP39 (SC) isolated from Tibetan kefir grain on colon inflammation and colorectal carcinogenesis. Azoxymethane (AOM) and dextran sulfate sodium (DSS) were used to establish a mouse model of colorectal cancer (CRC). The treatment group mice were administered with LK, SC, or the combination of LK and SC for five days per week from the day of receiving AOM. The composition of the gut microbiota was assessed using internal transcribed spacer 2 and 16S rRNA gene high-throughput sequencing. Furthermore, the biomarkers associated with gut barrier integrity, inflammation, regulators of cell proliferation, and apoptosis were evaluated. The results showed that the administration of LK, SC, and their combination increased the body weights and decreased the disease activity index (DAI) score and tumor multiplicity. As compared to the CRC model group, the three treatment groups positively regulated the gut microbiota. Meanwhile, the three treatments also enhanced the gut barrier, decreased the expression of proinflammatory cytokines and oncocyte proliferation indicators, and increased the expression of terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive tumor epithelial cells and content of short chain fatty acids in fecal samples. All these results indicated that the LK and SC alleviated the inflammation and colorectal carcinogenesis in AOM/DSS-induced CRC mouse models, and the majority of tested indexes in the combination group were superior to single strain groups.