TLR4 and renal fibrosis: LPS interaction with TLR4 activates NF-κB signaling pathways, which mediates the secretion of a large number of inflammatory cytokines (TNF⁃α, IL⁃6, IL⁃1β) and chemotactic proteins, such as MCP⁃1, to strengthen the inflammatory response of the kidney and form an “inflammatory cascade” that finally results in renal fibrosis.