The role of gut microbiota on skeletal muscle strength in LDLR knockdown aging mice.

To investigate the role of gut microbiota and bile acids metabolism on skeletal muscle strength in low density lipoprotein receptor (LDLR) knockdown aging mice. Forty-eight male C57BL/6J mice were employed in the experiment, twelve adult mice and twelve old mice were separately knocked down skeletal muscle LDLR (ALKd group, OLKd group). Other adult mice and old mice were injected with empty vectors as control (Acon group, Ocon group). After eight weeks of injection, each mouse was tested for skeletal muscle strength. The serum glycolipid biomarkers, the gut microbiota composition, the ileum apical sodium-dependent bile acid transporter (ASBT), farnesoid X receptor (FXR), fibroblast growth factor 15 (FGF15), and gastrocnemius fibroblast growth factor receptor 4 (FGFR4) were detected. When compared to the Ocon group, increased grip strength, and the relative abundance of Akkermansia and Ileibacterium were found in the OLKd group. The FGF15 protein of the ileum and FGFR4 protein of the gastrocnemius were found to increase in the OLKd group than those of the Ocon group. The gut microbiota and bile acid metabolism both play an important role in the partially improved skeletal muscle strength of LDLR knockdown aging mice.