Li Ming, Xi Ya-Ming, Chen Che, Chu Hui-Yuan, Zhang Hao, Li Pei, Deng Wei
Department of Hematology, Lanzhou University First Hospital, Lanzhou , Gansu Province, China.
Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2011 Aug;19(4):894-7.
This study was aimed to investigate the effect of clostridium difficile toxin A (Tcd A) on proliferation of K562 cells and its mechanism. The proliferative activity of K562 cells exposed to Tcd A was tested by MTT assay; cell cycle distribution and mitochondrial membrane potential were analyzed by flow cytometry; the protein expression of cytochrome C and DNA fragmentation were observed by immunohistochemistry staining and agarose gel electrophoresis respectively. The results indicated that Tcd A inhibited proliferation of K562 cells in a time-and concentration-dependent manner. Cells were arrested at G(0)/G(1) phase. Peak of apoptosis appeared. The protein expression of cytochrome C increased as compared with control group (p < 0.05). Agarose gel electrophoresis of DNA from K562 treated with Tcd A revealed a "ladder" pattern. It is concluded that clostridium difficile toxin A can inhibit proliferation and induce apoptosis of K562 cells. The mechanism may be in relation to decrease of mitochondrial membrane potential and the release of cytochrome C from mitochondria matrix.
本研究旨在探讨艰难梭菌毒素A（Tcd A）对K562细胞增殖的影响及其机制。采用MTT法检测Tcd A作用后K562细胞的增殖活性；通过流式细胞术分析细胞周期分布及线粒体膜电位；分别采用免疫组织化学染色和琼脂糖凝胶电泳观察细胞色素C蛋白表达及DNA片段化情况。结果表明，Tcd A以时间和浓度依赖的方式抑制K562细胞增殖。细胞阻滞于G(0)/G(1)期，出现凋亡峰。与对照组相比，细胞色素C蛋白表达增加（p < 0.05）。Tcd A处理后的K562细胞DNA琼脂糖凝胶电泳呈现“梯状”条带。结论：艰难梭菌毒素A可抑制K562细胞增殖并诱导其凋亡。其机制可能与线粒体膜电位降低及细胞色素C从线粒体基质释放有关。
