TGFB1 and renal fibrosis: Rong et al. studied type 2 diabetic db/db mice and HG-induced HK-2 cells and found that berberine decreased the expression of alpha smooth muscle actin (α-SMA), collagen I, collagen IV, FN, and TGF-β1, thus reducing renal tubulointerstitial injury and renal fibrosis in diabetic db/db mice.