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目的 :研究细胞凋亡及一些凋亡相关基因 (p53,bcl 2 ,bax)的表达在急性放射性皮肤溃疡发生发展过程中的作用。方法 :采用Wistar大鼠以6 0 Coγ射线进行局部照射 ,建立急性放射性皮肤溃疡动物模型 ,观察病变 4 0d ,然后采用免疫组化方法检测皮肤溃疡组织中P53,Bcl 2 ,Bax蛋白表达 ,并采用原位末端标记法 (TUNEL)检测细胞凋亡。结果 :照后 14d照射野内开始出现皮肤溃疡 ,之后逐渐扩大、融合、加深 ;照后 11～ 4 0d ,P53蛋白表达明显增强 ,主要定位于血管内皮细胞和小血管平滑肌中 ;照后 14～ 2 1d为Bax蛋白表达高峰 ,之后逐渐减弱 ,主要定位于血管内皮细胞、部分成纤维细胞及新生表皮细胞中 ;Bcl 2则在照后 1～ 11d呈弱或中度阳性 ,定位于表皮、毛囊上皮及血管内皮中 ,之后为阴性或可疑阳性 ;照后 11～ 35d ,上述细胞特别是血管内皮细胞凋亡率较正常伤口愈合早期增高。结论 :辐射诱导的P53,Bax ,Bcl 2表达的变化及细胞凋亡率特别是血管内皮细胞凋亡率的增高与放射性皮肤溃疡发生、发展及难愈合 (不能形成有效肉芽组织 )的分子机制相关
Objective: To study the role of apoptosis and expression of some apoptosis-related genes (p53, bcl 2 and bax) in the development of acute radiation-induced skin ulcers. METHODS: Wistar rats were irradiated with 60 Co γ-rays to establish an animal model of acute radiation skin ulcer. The lesions were observed for 40 days. The expression of P53, Bcl 2 and Bax protein in skin ulcer tissues was detected by immunohistochemistry. Apoptosis was detected by TUNEL. RESULTS: Skin ulcers began to appear within 14 days after irradiation, and then gradually enlarged, merged, and deepened. After 11 to 40 days, the expression of P53 protein was significantly enhanced, mainly localized in vascular endothelial cells and small blood vessel smooth muscle; 14 to 2 after exposure. 1d was the peak expression of Bax protein, then gradually weakened, mainly localized in vascular endothelial cells, some fibroblasts, and neonatal epidermal cells; Bcl 2 was weak or moderately positive in 1 to 11 days after irradiation, localized to the epidermis and hair follicle epithelium. And in the vascular endothelium, it was negative or suspiciously positive; after 11 to 35 days, the apoptotic rate of the above-mentioned cells, especially vascular endothelial cells, was higher than that of normal wounds. Conclusion : Radiation-induced changes in the expression of P53, Bax, and Bcl 2 and apoptosis rate, especially in vascular endothelial cells, are related to the molecular mechanism of the occurrence, development, and difficult healing of radioactive skin ulcers (cannot form effective granulation tissue)