结肠腺癌组织细胞的凋亡和Bax/Bcl-2蛋白的表达

Apoptosis of cells and expressions of Bax and Bcl-2 in human colonic adenocarcinoma

目的研究结肠腺癌组织细胞的凋亡、Bcl-2家族主要基因/蛋白（Bax和Bcl-2）的表达及Bax/Bcl-2比值在结肠腺癌发生和发展过程中的作用。方法选取临床标本50例,包括20例结肠腺癌组织和30例正常结肠黏膜组织。分别使用TUNEL法和免疫组化法检测细胞凋亡及其相关蛋白的表达。结果结肠腺癌组织和正常结肠组织细胞凋亡指数的中位数分别为0.26（四分位数间距0.09~0.59）和1.57（0.85~13.13）,结肠腺癌组织的细胞凋亡水平明显低于正常结肠组织（P〈0.001）。Bax蛋白在两种组织中的阳性表达率分别为95%（19/20）和53.3%（16/30）,差异有统计学意义（P=0.002）;Bcl-2的阳性表达率分别为70%（14/20）和46.7%（14/30）,差异无统计学意义（P=0.103）。Bax/Bcl-2≥1的样本数在两种组织中分别为70%（14/20）和36.7%（11/30）（P=0.021）,差异有统计学意义。结论结肠腺癌组织的细胞凋亡水平明显低于正常结肠组织,Bax蛋白在结肠腺癌组织中的表达明显强于正常结肠组织,Bcl-2蛋白的表达未见明显差异,Bax/Bcl-2比值在结肠腺癌的发生和发展过程中可能发挥正相关作用。

Objective To examine the apoptosis of cells,expression of two major apoptosis-related proteins,Bax and Bcl-2,and the role of Bax/Bcl-2 ratio in human colonic adenocarcinoma.Methods Fifty samples were examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling（TUNEL） and immunohistochemistry,including 20 cases of colonic adenocarcinoma and 30 cases of normal colonic mucosa.Results A significantly lower level of enterocyte apoptosis was observed in human colonic adenocarcinomas compared with normal colonic mucosa（median of apoptotic index,0.26 vs 1.57,P0.001）.There were obvious difference in Bax protein（positive expression,95.0% vs 53.3%,P=0.002） and Bax/Bcl-2 ratio（percent of samples having a ratio ≥1,70.0% vs 36.7%,P=0.021） between colonic adenocarcinoma and normal colonic mucosa,but there was not different in Bcl-2 between the two groups（70% vs 46.7%,P=0.103）.Conclusion Decreased apoptosis and expression of protein Bax and Bax/Bcl-2 ratio,not protein Bcl-2,may play some roles in the onset and development of human colonic adenocarcinoma.However,the results are contrary to traditional viewpoints and more studies are required for a better understanding of these changes.