Lactuca indica L. polysaccharide ameliorates type 1 diabetes via gut microbiota-SCFAs-IRS-1/PI3K/GLUT4-MYD88/NF-κB axis.

Lactuca indica L. is both edible and medicinal, and has various effects such as antioxidant and anticardiovascular diseases. Lactuca indica L. polysaccharide (LIP) is the active constituent of Lactuca indica L. The goal of this study was to provide a preliminary analysis of the structural properties of LIP and to investigate its therapeutic efficacy and possible mechanisms in STZ-induced T1DM. This study isolated a homogeneous polysaccharide, designated LIP, from the crude polysaccharide of Lactuca indica L. This polysaccharide is an acidic polysaccharide consisting of eight monosaccharides. LIP has significant therapeutic effects on T1DM mice, can regulate abnormal glucose metabolism, inhibit excessive inflammation, and alleviate pancreatic and hepatic damage. Furthermore, LIP modulated hepatic insulin signaling and inflammatory pathways, as well as restored the balance of the intestinal microbiota, particularly with regard to the increase in SCFAs-producing bacteria. There is a significant correlation among them. In conclusion, LIP may be a candidate agent to treat diabetes.