Protective effect of melatonin on cigarette smoke-induced restenosis in rat carotid arteries after balloon injury

Vascular restenosis after the interventional angioplasty remains the main obstacle to a favorable long-term patency. Many researches suggest cigarette smoking is one of the most important causes of restenosis. This study was designed to investigate whether melatonin could protect against the cigarette smoke-induced restenosis in rat carotid arteries after balloon injury. Three groups of male rats (normal condition, cigarette smoke exposed, cigarette smoke exposed, and melatonin injected) were used in this study. An established balloon-induced carotid artery injury was performed, and the carotid arteries were harvested from these three groups 14 days later. The ratio of intima to media, the infiltration of inflammatory cells, the expression of inflammatory cytokines (NF-κB, IL-1β, IL-6, TNF-α, MCP-1), adhesion molecules (ICAM-1, VCAM-1), and eNOS were measured. The results showed that cigarette smoke exposure aggravated the stenosis of the lumen, promoted the infiltration of inflammatory cells and induced the expression of the inflammatory cytokines and adhesion molecules after the balloon-induced carotid artery injury. Moreover, cigarette smoke exposure can inhibit the expression of eNOS. Particularly, we surprised that melatonin could minimize this effect caused by cigarette smoke. These results suggested that melatonin could prevent the cigarette smoke-induced restenosis in rat carotid arteries after balloon injury and the mechanism of its protective effect may be the inhibition of the inflammatory reaction. This also implies melatonin has the potential therapeutic applicability in prevention of restenosis after the vascular angioplasty in smokers.