| The proliferation and migration of vascular smooth muscle cells (VSMCs) play important roles in the development of restenosis after percutaneous transluminal coronary angioplasty. Atorvastatin (AT) is a novel hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor for the treatment of hypercholesterolemia, and has pleiotropic effects such as antiinflammatory and anti-atherosclerosis. Beyond causing vasodilation through inhibition of calcium channels, long-acting calcium channel blocker amlodipine besylate (AM) has been demonstrated to produce clinical benefits in patients with coronary artery disease. To investigate whether AM and AT have additive beneficial effects on the neointimal hyperplasia, the present study detected the effects of AM and AT alone and combination of both drugs (AT+AM) on the neointimal hyperplasia after balloon injury and the related mechanisms.Methods and Results:1 AM and AT inhibit neointimal hyperplasia induced by balloon injuryMorphology analysis showed that the injured group showed marked neointimal formation at 14 days after balloon injury. The I/M (intima/media) ratio in injured group was 3.40±0.17. However, AM alone and AT+AM significantly reduced neointimal hyperplasia and I/M ratio (AM, 1.86±0.26; AT+AM, 0.58±0.23), compared with injured group (P < 0.01), respectively. The inhibitory effects in AT+AM group was more than that of AM alone (P < 0.01), while AT alone merely showed a slight effect.2 AM and AT inhibit the expression of PCNA and KLF5 in neointima induced by balloon injuryImmunohistochemical staining showed that the expression of PCNA (proliferating cell nuclear antigen) and KLF5 (Krüppel-like factor 5) was rarely detected in carotid arteries of sham group. However, the number of PCNA and KLF5 positive cells was markedly increased at 14 days after balloon injury, and significantly reduced in groups treated with AM alone and combination with AT, compared with that of injured group (P < 0.01).3 AM and AT inhibit the expression of migration related proteins in neointima induced by balloon injuryImmunohistochemical staining showed that the expression of VCAM-1 (vascular cell adhesion molecule 1), ICAM-1 (intercellular adhesion molecule 1), OPN (osteopontin) and MMP-9 (matrix metalloproteinases 9) was rarely detected in carotid arteries of sham group. However, the number of VCAM-1, ICAM-1, OPN and MMP-9 positive cells in injured group was significantly increased at 14 days after balloon injury, respectively. The expression of VCAM-1, ICAM-1, OPN and MMP-9 in neointima injured by balloon was significantly reduced following treatment with AM alone and combination with AT, compared with that of injured group (P < 0.01).4 AM inhibits the proliferation of VSMCs induced by serum in vitro Cell counting analysis showed that AM treatment resulted in a significant reduction of VSMC proliferation activity in a dose-dependent manner (P < 0.05). Western blot analysis also showed that the expression of proliferation marker proteins PCNA, KLF5, and c-Jun was significantly reduced in VSMCs treated with AM (5, 10 ng/ml) in a dose-dependent manner (P < 0.05).5 AM inhibits the migration of VSMCs induced by serum in vitro Wound healing assays showed that the migration activity of VSMCs was significantly decreased in a dose-dependent manner after incubation with AM (5, 10 ng/ml), compared with serum-treated group (P < 0.05). Zymography analysis also showed that the activity of MMP-2 (matrix metalloproteinases 2) and MMP-9 in VSMCs was significantly decreased in a dose-dependent manner (P < 0.05) under the same conditions.Conclusions:1 AM alone and combination with AT inhibit neointimal hyperplasia induced by balloon injury in carotid arteries of rats. 2 AM alone and combination with AT inhibit the expression of PCNA, KLF5, VCAM-1, ICAM-1, OPN and MMP-9 in neointima induced by balloon injury.3 AM inhibits the expression of PCNA, KLF5, c-Jun, MMP-2 and MMP-9 in VSMCs in vitro.4 AM inhibits neointimal hyperplasia induced by balloon injury via inhibiting the proliferation and migration of VSMCs. |
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