Abstract: Objective: To find the key intestinal flora correlated with the development of middle-aged men's metabolic syndrome, and discuss the microbiological mechanism of the intervention of Wuqinxi on middle-aged men's metabolic syndrome. Methods: Sixty participants were randomly divided into four groups: health control group, health Wuqinxi group, metabolic syndrome control group and metabolic syndrome Wuqinxi group. Health control group and metabolic syndrome control group remained their normal lifestyle and no intervention was applied, whereas health Wuqinxi group and metabolic syndrome Wuqinxi group received Wuqinxi interventional training for 6 months. Intestinal flora, lipopolysaccharide, short-chain fatty acid, glucagon-like peptide-1, glucagon-like peptide-2, fasting blood glucose, fasting insulin, insulin resistance index of participants from four groups were assessed at four time points: one day before, two-, four-, and six-month after Wuqinxi interventional training. Results: The quantities of bifidobacteria, lactobacilli, bifidobacteria/scherichia coli and bacteria producing short-chain fatty acid were significantly decreased, and they were negatively correlated with insulin resistance index. The quantities of escherichia coli, staphylococcus and lipopolysaccharide were significantly increased, and they were positively correlated with insulin resistance index. The intestinal flora and its metabolites of middle-aged men who were healthy or patients with metabolic syndrome could be significantly optimized and the time-dose effect was also evident after Wuqinxi interventional training. Conclusion: It may be an important microbiological mechanism for improving middle-aged men's metabolic syndrome that the intestinal flora, lipopolysaccharide, short-chain fatty acid, glucagon-like peptide-1 and glucagon-like peptide-2 could be optimized after Wuqinxi interventional training.

Key words: Wuqinxi, middle-aged men, metabolic syndrome, intestinal flora