Effects of total C-21 steroidal glucosides from Cynanchum auriculatum on renal fibrosis in rats and mechanisms involved / 中草药

ABSTRACT

Objective: To investigate the effects of C-21 steroidal glucosides from Cynanchum auriculatum on renal fibrosis in rats caused by unilateral ureteral ligation and explore its mechanisms. Methods: A total of 15 rats were randomly chosen as sham operation group (Sham), while the remaining rats underwent unilateral ureteral ligation. The rats after the operation were randomly divided into four groups, namely the Sham operation group, the model group, the positive control group (20 mg/kg), C. auriculatum high group (400 mg/kg), C. auriculatum low group (200 mg/kg), 15 per group, and the rats in each group were administrated with corresponding drugs. After the intervention of 28 d, all the rats were sacrificed and the kidneys were then removed. The content of hydroxyproline was measured. HE and Masson staining were conducted to assess kidney pathological changes and renal fibrosis. The protein expression of TGF-β1, α-SMA, and E-cadherin were tested with immunohistochemistry and Western blotting. The mRNA expression of collagen-I and collagen-III was evaluated using qRT-PCR. Results: Compared with the model group, C-21 steroid glycosides significantly alleviated the kidney pathological injury and renal fibrosis, and reduced fibrous tissue and collagen proliferation. C-21 steroid glucosides from C. auriculatum can significantly reduce the kidney/body weight ratio and the content of hydroxyproline in kidney tissue (P < 0.05, 0.01), and it showed in a dose-dependent manner. Compared with the model group, the expression of α-SMA and TGF-β1 was decreased significantly, and the expression of E-cadherin was increased significantly (P < 0.05, 0.01) in C. auriculatum group. Moreover, compared with the model group, C-21 steroidal glucosides significantly down-regulated the mRNA expression of collagen-I and collagen-III mRNA (P < 0.01). Conclusion: C-21 steroid glycosides from C. auriculatum can effectively attenuate renal fibrosis in rats with unilateral ureteral ligation and its underlying mechanisms may be related to inhibiting the over-expression of collagen-I and collagen-III, down-regulating the expression of α-SMA and TGF-β1, and up-regulating the expression of E-cadherin. By regulating the tubular epithelial-mesenchymal transition, it exerts its anti-fibrotic effect.