雷帕霉素预防再狭窄的机制探讨

Mechanisms of rapamycin for prevention of restenosis

目的观察肌肉注射雷帕霉素对血管介入治疗后再狭窄的影响,探讨雷帕霉素防止再狭窄的可能机制。方法采用雄性新西兰白兔,给予高脂高胆固醇饮食复制成动脉粥样硬化模型后,再行髂动脉内膜损伤术复制再狭窄模型,随机分为3组:单纯损伤组、雷帕霉素组和联合用药组,雷帕霉素组和联合治疗组又随机分别分为2个亚组:低剂量组和高剂量组。分别对各组进行肌肉注射雷帕霉素、口服抗血小板药和调脂药的干预。4周后使用免疫组织化学方法检测血管壁增殖细胞核抗原(PCNA)表达阳性细胞,即增殖细胞;以及核因子κB(NF-κB)和细胞间黏附分子-1(ICAM-1)的表达;用计算机图像分析法观察血管组织形态学的变化,并对免疫组化结果进行定量分析。结果①雷帕霉素组与单纯损伤组相比:表示内膜增殖程度的指标显著减少(P<0.05),且随注射剂量的增大而改变(P<0.05);血管壁增殖细胞PCNA及NF-κB、ICAM-1的表达均降低(P<0.05),降低程度随注射剂量的增大而增强(P<0.05);②联合组和雷帕霉素组相比:表示内膜增殖程度的指标均减少(P<0.05),且随注射剂量的增大,上述指标的改变差异有统计学意义(P<0.05);血管壁增殖细胞PCNA及NF-κB、ICAM-1的表达降低(P<0.05),降低程度随注射剂量的增大而增强(P<0.05)。结论雷帕霉素可防止再狭窄的形成,在一定范围内注射剂量与新生内膜增殖程度有相关性,联合应用辛伐他汀和氯吡格雷进行干预比单用雷帕霉素效果更加明显。

Objective To investigate the effects of rapamycin on restenosis after interventional therapy and possible mechanism that underlies its protection against restenosis. Methods Male New Zealand white rabbits were given cholesterol diet（1% cholesterol,5% lard） for 6 weeks to induce atherosclerosis. Balloon injury was performed in the right iliac arteries of the rabbit to make models of restenosis. These rabbits were divided into the untreated injury control group,or rapamycin treatment group to receive intramuscular injection of rapamycin,or combined treatment group to receive rapamycin plus oral use of clopidogel and simavastatin. The treatment groups were further divided high-and low-dose groups. At 4 weeks later,immunohistochemistry was used to detect the cells with nuclear factor（NF-κB） -positive expression（proliferating cells） on vessel walls,as well as the expressions of NF-κB and intercellular adhesion molecule（ICAM-1） . Computer analysis of photomicrogram was performed to examine the histomorphology of iliac arteries and expressions of PCNA,NF-κB and ICAM-1. Results ①Compared with the untreated injury controls,rapamycin group showed significant reductions in markers of intimal proliferation（P0.05） ,in a dose-dependent manner（P0.05） ,and also in expressions of PCNA,NF-κB and ICAM-1（P0.05） in a dose-dependent manner（P0.05） . ②Compared with rapamycin group,combined treatment group showed significant reductions（P0.05） in a dose-dependent manner（P0.05） ,and in expressions of PCNA,NF-κB and ICAM-1（P0.05） in a dose-dependent manner（P0.05） . Conclusion Rapamycin could prevent restenosis with a conspicuous correlation between certain range of injection dose and proliferation of neointima. Rapamycin in combination with clopidogel and simvastatin may lead to more favorable treatment outcomes than Rapamycin alone.