Effects of Clostridium tyrobutyricum on Lipid Metabolism, Intestinal Barrier Function, and Gut Microbiota in Obese Mice Induced by High-Fat Diet

Obesity and its complications constitute a main threat to global human health. The purpose of this investigation was to explore the influences of Clostridium tyrobutyricum (Ct) on lipid metabolism, intestinal barrier function, and intestinal microbiome in obese mice induced by a high-fat diet (HFD). After establishing the obesity model, 107 CFU/mL and 108 CFU/mL C. tyrobutyricum were used to intervene in HFD-fed mice by gavage for six weeks, and indexes related to obesity were measured. In the liver of HFD-fed mice, the results revealed that C. tyrobutyricum reduced liver weight and the levels of triglyceride (TG), total cholesterol (TC), and nonesterified fatty acid (NEFA), along with decreasing red lipid droplets and fat vacuoles. After C. tyrobutyricum intervention, the mRNA expression of peroxisome proliferator-activated receptor-γ (PPARγ) was downregulated, and AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor-α (PPARα), adipose triglyceride lipase (ATGL), and hormone-sensitive lipase (HSL) were upregulated in the liver. Additionally, C. tyrobutyricum alleviated intestinal morphology injury caused by HFD, decreased the expression of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and IL-1β in the colon, and upregulated tight junction protein expression. In addition, 16S rRNA sequencing revealed that C. tyrobutyricum increases the diversity of intestinal microbiota. Overall, C. tyrobutyricum improved HFD-induced lipid metabolism disorders, preserved the intestinal barrier's integrity, and modulated the structure of the intestinal microbiome. These findings provide a novel insight into the role of C. tyrobutyricum as a probiotic in regulating lipid metabolism.

Clostridium tyrobutyricum Protects against LPS-Induced Colonic Inflammation via IL-22 Signaling in Mice

This study aimed to investigate the effects of Clostridium tyrobutyricum (C. tyrobutyricum) on colonic immunity and the role of IL-22 in the protective function of C. tyrobutyricum. Mice were supplemented with 108 CFU/mL C. tyrobutyricum daily for 20 days, followed by injecting with LPS for 24 h. In vivo interference of IL-22 via injecting with an adeno-associated virus was conducted to elucidate the role of IL-22 in C. tyrobutyricum attenuating colonic inflammation. The results showed that C. tyrobutyricum decreased the mRNA expression of IL-6 and IL-1β. C. tyrobutyricum enhanced the mRNA expression of IL-22 and the expression of MUC2 in the colon. The in vivo interference results showed that C. tyrobutyricum enhanced the mRNA expression of IL-6 and IL-1β while decreased the expression of MUC2 after knocking down IL-22. The flow cytometric analysis showed that C. tyrobutyricum decreased the proportions of macrophages, DCs, and mast cells and effectively regulated the proportion of Th17 cells, indicating that C. tyrobutyricum may stimulate the expression of IL-22 via regulating Th17 cells. Our study concluded that C. tyrobutyricum protected against LPS-induced colonic barrier dysfunction and inflammation via IL-22 signaling, suggesting that C. tyrobutyricum could be a potential probiotic in regulating colonic health.