IL6 and renal fibrosis: Furthermore, renal fibrosis results in a progressive decline of renal function, ultimately entering the UR stage (Klahr and Morrissey 2002), which is marked by a notable rise in the expression levels of fibroblast markers α-SMA and TGF-β1 (Li et al. 2019), along with the heightened secretion of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β.