Ginsenoside Rb1 inhibits the carotid neointimal hyperplasia induced by balloon injury in rats via suppressing the phenotype modulation of vascular smooth muscle cells

This study aims to investigate the effects of ginsenoside Rb1 on vascular intimal hyperplasia in rats and explore the mechanisms. The rat vascular neointimal hyperplasia model was made by rubbing the endothelia of carotid artery with a balloon and Rb1 (10 and 30 mg/kg/day) was given the day after surgery for 14 consecutive days. The neointimal hyperplasia level and the degree of vascular smooth muscle cells (VSMCs) proliferation were evaluated by histopathology and by calculating the proliferating cell nuclear antigen (PCNA) positive expression percentage; protein expressions of PCNA, phosphorylation extracellular signal-regulated kinase 1/2 (pERK1/2), smooth muscle α-actin (SM α-actin), and the mRNA expressions of proto-oncogene c-myc, SM α-actin, SM-emb (embryonic smooth muscle myosin heavy chain) and p38 MAPK were detected by immunohistochemistry and Real Time RT-PCR, respectively. Compared with the endothelia rubbing model group, Rb1 10 and 30 mg/kg/day medication significantly ameliorated the neointimal hyperplasia (P < 0.05), and decreased the positive expression percentage of PCNA(P < 0.05). Rb1 medication also significantly decreased the elevated protein expression of pERK1/2 and the mRNA expression of c-myc(P < 0.05), and tended to reduce the expression of p38 MAPK mRNA. Endothelial rubbing increased the SM-emb mRNA expression, but decreased the expression of SM α-actin mRNA which was reversed by Rb1 (P < 0.05). The results indicate that Rb1 inhibits the vascular neointimal hyperplasia induced by balloon-injury in rats via suppressing the VSMC proliferation, which may be involved in part the inhibition of pERK1/2 protein and related to its inhibition on VSMC phenotype modulation.