兔动脉内膜损伤后增生内膜中c-myc、c-fos和p53基因表达与细胞凋亡的研究

A study on c-myc, c-fos and p53 gene expressions and SMC apoptosis in proliferative intima of rabbit injured arteries

目的探讨动脉内膜损伤后内膜增殖灶中平滑肌细胞凋亡现象及其相关调控基因的表达.方法取血管内膜损伤后4小时、24小时、7天、14天、28天、3个月、4个月时的兔动脉进行光镜、电镜检查、原位细胞凋亡标记实验(TUNEL)以及c-fos、c-myc、p53mRNA原位杂交实验.结果电镜观察到凋亡细胞早期的表现;7～120天内膜中细胞凋亡的发生率仅为1%～2%左右;原位杂交显示7天组c-fos、c-myc呈阳性表达,以后表达强度逐渐下降直至转阴,与内膜细胞增殖动力学变化的趋势一致,p53仅在7天组有弱阳性表达.结论动脉内膜损伤后增殖灶中细胞凋亡的作用非常微弱,在内膜增殖的形成中不是主要的影响因素.c-fos、c-myc、p53基因的表达与内膜中平滑肌细胞增殖动力学和细胞凋亡的变化趋势相吻合.

Objective to evaluate the effect of SMC apoptosis in the proliferous intima of injured arteries and relationship between c-myc, c-fos, p53 gene expressions and the kinetics of SMC proliferation. Methods The histological chnges of rabbit abdominal aorta were observed by light microscope and electron microscope at 4 hours, 1 day, 7 days, 14 days, 28 days, 3 months and 4 months after the artery intima was injured. And SMC apoptosis was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling(TUNEL). The expressions of c:myc, c-fos and p53 were tested by in situ hybridization assay. Results Only early apoptotic ultrastructures of proliferative SMC of intima were observed under electron microscope; 1% -2% of intima cell apoptosis was indicated by TUNEL from 7 day to 4 month groups ;c-myc and c-fos were highly expressed in 7 day group and then decreased gradually to negative, being coincident with the pattern of intima proliferation; p53 was slightly expressed only in 7 day group and could not be tested thereafter. Conclusions Cell apoptosis was not an important interference factor in the formation of hyperplasic intima. The expressions of c-fos, c-myc and p53 have a coincident relationship with the kinetics of SMC proliferation and apoptosis in injured rabbit arteries.