镍钛自膨胀支架置入血管后细胞凋亡与增生的实验观察

Experimental observation on apoptosis and proliferation of smooth muscle cells after implantation of NITI self-expanding stent

目的 血管内支架置入后的再狭窄是尚未解决的主要课题 ,本研究对置入镍钛 (NITI)自膨胀支架的动物进行研究 ,观察支架置入后血管平滑肌细胞 (VSMC)的凋亡与增生的关系 ,为再狭窄的防治提供新的方法。方法 在兔的腹主动脉内置入 30个NITI合金自膨胀支架 ,按不同时间处死动物 ,采用电镜和 3′ 末端DNA原位标记法 (TUNEL)观察VSMC的凋亡。结果 从支架置入后的 2 4h到 8周 ,支架置入部位均可见到凋亡的VSMC ,3～ 6周时 ,凋亡达到高峰 ,8周以后凋亡细胞开始减少。凋亡的细胞主要分布于血管的新生内膜层 ,但中膜层也存在有少量的凋亡细胞。结论 NITI自膨胀支架置入后 ,不仅有SMC的增生 ,也有SMC的凋亡。

Objective Stent implantation is the most important achievement in the therapy of cardiovascular diseases.Stent can prevent restenosis,but it can not reduce the proliferation of smooth muscle cells.Now,most methods of treating restenosis aim at inhibiting proliferation of SMCs.The objective of the present study was to observe the effects of apoptosis on the restenosis after stenting.Methods 30 rabbits were studied and 30 NITI stents were implanted in the normal abdominal aorta.TUNEL and electron microscope were used to examine the apoptosis cells.Results Apoptosis cells appeared in the wall of stenting segment from 24hr to 8 weeks after implantation of the stent,with the peak of apoptosis between 3-6 weeks,while the new intima was formed completely and covered by a single layer of cells-endotheliocyte.The apoptosis cells were distributed in both new intima and media.Conclusion After implantation of stent,the SMCS not only proliferate but also die (apoptosis),which may play an important role in maintaining the number of SMCs.Increase in apoptosis cells may reduce restenosis after stenting.