Abstract

Objective: It is acknowledged that Radix Rehmanniae Praeparata (RR) can regulate hormone metabolism, reduce blood glucose, resist aging, help to sedate patients and promote diuresis. The study aims to investigate the mechanism of how RR influences the development of renal fibrosis by regulating the miR-122-5p/PKM axis. Methods: Unilateral ureteral obstruction (UUO) was applied to induce renal fibrosis in mice in vivo , and human tubular epithelial HK2 cells treated by transforming growth factor-β (TGF-β1) were used to induce renal fibrosis in vitro . Interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) in mouse serum were detected by Enzyme-linked immunosorbent assay (ELISA); fibronectin (FN) and type I collagen (Col-I) in renal tissue were detected by Western blotting; serum creatinine (Cr) and blood urea nitrogen (BUN) were analyzed by kits. Hematoxylin-eosin (HE) staining and Masson staining were utilized to assess the degree of pathological damage and fibrosis. Cell viability and apoptosis in the in vitro model were detected by MTT and Flow cytometry. Dual-luciferase reporter assay was performed to determine intermolecular targeting relationships. Results: RR could inhibit IL-6 and TNF-α levels, decrease the levels of FN and Col-I and improve the renal function indexes (serum Cr and BUN) in UUO mice (all P<0.05). In addition, RR was able to promote the up-regulation of miR-122-5p expression in UUO mice in vivo (P<0.05). MiR-122-5p expression was down-regulated and PKM expression was up-regulated in HK2 cells treated with TGF-β1 (all P<0.05). RR inhibited renal fibrosis progression by regulating the miR-122-5p/PKM axis. Inhibition of miR-122-5p or overexpression of PKM could promote apoptosis of TGF-β1-treated HK2 cells, inhibit their viability, aggravate fibrosis, and attenuate the protective effect of RR on the cells. The protective effect of RR promoted by overexpression of miR-122-5p was partially counteracted by PKM. Conclusion: RR can inhibit ren