犬冠状动脉支架植入术后细胞凋亡及凋亡相关基因蛋白表达的变化

目的观察犬冠状动脉支架植入术后血管内膜凋亡及凋亡相关基因蛋白表达的动态变化.方法15只犬进行冠状动脉左回旋支支架植入术,前降支相应血管作为对照,分别于术后1周、4周和12周处死,进行病理学检查、TUNEL法和透射电镜检测凋亡细胞、PCNA和Bcl-xl免疫组织化学染色以及Bcl-xl蛋白质印迹杂交.结果支架植入术后1～12周内膜面积持续增加;正常血管未见凋亡细胞和PCNA阳性细胞,术后1周内膜中凋亡细胞阳性率和PCNA阳性细胞率均达高峰,术后4周和12周不断降低,但凋亡细胞阳性率在各时间段均低于PCNA阳性细胞率;Bcl-xl免疫组织化学染色和蛋白印迹杂交均显示正常对照血管偶见表达,术后1周在内膜中表达增加,术后4周在内膜中大量表达,并可维持至12周.结论细胞凋亡相对不足可能是支架植入术后再狭窄形成的一个原因,Bcl-xl在内膜中高表达可能是造成细胞凋亡相对不足的因素之一.

Changes of apoptosis and expression of related apoptosis regulatory factors in neointima after canine coronary angioplasty

Objective To investigate the changes of apoptosis and expression of related apoptosis regulatory factors in neointima after canine coronary angioplasty Methods Stents were implanted in the left circumflex coronary artery in 15 canines Arteries were harvested at 1, 4, and 12 weeks after stenting Uninjured arteries were used as controls Apoptosis was demonstrated by the terminal uridine nick end labeling (TUNEL) method and transmission electron microscopy Proliferating cells were identified by immunostaining for proliferating cell nuclear antigen (PCNA) Expressions of Bcl xl proteins were detected by immunohistochemical method and Western blot Results Stents implantment induced intimal hyperplasia Apoptosis was not detected in control vessels Apoptotic cells and PCNA positive cells were identified at 1, 4, and 12 weeks with a peak at 1 week Profiles of apoptosis and cell proliferation after stenting were accordant in neointima, but cell proliferation rates were higher than cell apoptosis rates at all time points Expressions of Bcl-xl proteins were detected at 1 week, peaked at 4 weeks, and lasted till 12 weeks after stenting Conclusion Apoptosis may be an important determinant of in stent restenosis Bcl xl appears to play a critical role in regulating cell apoptosis