Objective: To explore the mechanism of Salidroside regulating the phenotypic transformation of cavernous smooth muscle cells (CCSMCs) in rats.
Methods: Primary CCSMCs were isolated from male SD rats, cultured in hypoxic environment for 24 hours, and treated with Salidroside at 30 μg/mL. Then the expressions of HIF-1α, platelet-derived growth factor receptor (PDGFR) and phenotypic transformation-related proteins α-SMA and Collagen I were detected by Western blot. The culture system of the CCSMCs was treated with exogenous PDGF-BB at 20 ng/mL for 24 hours, and the effects of Salidroside or PDGFR inhibitor Crenolanib (100 nmol/L) were observed. The expressions of PDGFR, phosphorylated PDGFR, phenotypic transformation-related proteins α-SMA and Collagen I, STAT3, phosphorylated STAT3, STAT5 and phosphorylated STAT5 were determined by Western blot. The intervention effects of Salidroside and/or the overexpression of STAT3 were observed after stimulation of the CCSMCs by exogenous PDGF-BB, followed by detection of the expressions of phenotypic transformation-related proteins α-SMA and Collagen I, STAT3 and phosphorylated STAT3 proteins.
Results: The expression of HIF-1α in the CCSMCs was significantly upregulated after cultured in hypoxic environment for 24 hours (P < 0.05), suggesting the successful construction of the hypoxia model of CCSMCs. Meanwhile, the expressions of PDGFRα, PDGFRβ and Collagen I were remarkably increased (all P < 0.05), and that of α-SMA markedly decreased (P < 0.05) in the CCSMCs. However, the expressions of the all the proteins above were significantly inhibited by Salidroside intervention (all P < 0.05). After stimulated by exogenous PDGF-BB for 24 hours, the phosphorylation ratios of PDGFRα, PDGFRβ and STAT3 and the expression of Collagen I were significantly elevated (all P < 0.05), that of α-SMA remarkably reduced (P < 0.05), and all were inhibited by intervention with crenolanib or Salidroside (all P < 0.05). No statistically significant difference was observed in the STAT5 phosphorylation ratio between different groups (P > 0.05). Overexpression of STAT3 in the CCSMCs treated with exogenous PDGF-BB and Salidroside significantly decreased the expression of α-SMA (P < 0.05) and increased that of Collagen I (P < 0.05).
Conclusion: Salidroside could improve the phenotypic transformation of CCSMCs in male rats through the PDGFR/STAT3 signaling pathway, which needs further exploration and verification.
Keywords: corpus cavernosum smooth muscle cell; phenotypic transformation; hypoxia; Salidroside; platelet-derived growth factor receptor; signal transducer and activator of transcription 3; rat.