TLR4 and type 2 diabetes mellitus: Administration of HQLHS inhibits harmful bacteria and enriches beneficial ones, especially Christensenella, which alleviates type 2 diabetes by promoting GLP-1 secretion, regulating hepatic glucose metabolism, inhibiting intestinal glucose absorption, enhancing intestinal barrier, reducing inflammation via LPS/TLR4/NF-κB pathway, and improving liver metabolism.