血管去内皮损伤后平滑肌细胞凋亡的实验观察

The experimental observation of apoptosis of vascular smooth muscle cells after vascular endothelium denudation

目的 了解血管去内皮损伤后新内膜形成及平滑肌细胞(SMCs)凋亡的时相变化。方法用氮气干燥剥脱大鼠颈动脉内皮复制血管损伤模型,HE染色光镜形态计量内膜/中膜比(I/M),末端脱氧核苷酸转移酶(TdT)介导的荧光素d-uTP缺口末端标记(TRNEL)方法观察不同时间新内膜形成(I/M)及VSMC凋亡。结果 血管去内皮后四天,在SMCs增生形成的新内膜中有TUNEL法证实的细胞凋亡,I/M加比,凋亡指数(TUNELI)分别为0.12±0.06,2.4±1.98。在七天,内膜明显增厚(I/M为0.6±0.15,与四天比,P<0.05),TUNELI达到最大值(为9.3±3.8,与四天比,P<0.05)。到第14天,内膜明显增厚约为中膜的1.25倍(I/M比1.25±0.14,与七天比,P<0.05),TUNELI逐渐减小(为8.75±4.01;与七天比,P>0.05)。损伤后21天,内膜开始变薄(I/M比为0.98±0.41,与14天比,P<0.05),凋亡水平进一步下降(TUNELI为6.58±3.97,但差异无显著性,P=NS)。结论 血管壁对损伤刺激诱发增生反应的同时激活凋亡机制。凋亡调节血管壁细胞数和内膜增厚演变。细胞凋亡的平衡失调可能是动脉粥样硬化(AS)、再狭窄(RS)等血管疾病发生的机制之一。

Objective To observe the time course of apoptosis of vascular smooth muscle cells (VSMC) after vascular injury. Methods The neointimal formation and apoptosis of VSMC were examined in a nitrogen air dry denuded-endothe-lium rat carotid model with HE staining, and terminal deoxynucleotide transferase (TdT) mediated-fluorosceine d-uTP nick-end labelling (TUNED. Results 4 days after vascular injury, the apoptosis of VSMC identified with TUNEL method had been found in the neointima ,intima/media ratio (I/M), and TUNEL index were 0. 12 + 0. 06,2. 4+1. 98,repectively. In 7 days, neointima thickened markedly and TUNELI increased to maximum (I/M 0.6 + 0. 15 and TUNELI 9. 3 + 3. 8,vs those in 4 days, P < 0. 05, respectively. ). In 14 days, the thickness of neointima was 1.25 fold that of media, TUNELI began to decrease (8. 75 + 4. 01,vs that in 7 days,P> 0. 05). By 21 days,the thickness of neointima began to decrease (0. 98 + 0. 41, P < 0. 05) and TUNELI was furthur decreased (6. 58 + 3. 97, P = NS). Conclusion Apoptosis of VSMC induced by vascular injury occurred concomitantly with the neointimal formation, apoptosis modulate the cell number in vascular wall and inti-mal thickening evolution, imbalance of apoptosis of VSMC may be one of the mechanism of the development and progression of atheroclerosis and restenosis.