产单核细胞李斯特菌诱导胸腺细胞凋亡及其基因调控

Apoptosis of Mouse Thymocytes and Its Gene Regulation Induced by Listeria Monocytogenesis

为研究产单核细胞李斯特菌 (LM )感染对小鼠胸腺细胞凋亡的诱导作用及胸腺细胞凋亡过程中的基因调控 ,小鼠经尾静脉注射LM后 ,以DNA琼脂糖凝胶电泳和流式细胞仪 (FCM )检测细胞凋亡及凋亡细胞的基因产物表达水平。结果表明LM能诱导小鼠胸腺细胞凋亡 ,琼脂糖凝胶电泳分析显示胸腺细胞出现典型的DNA“梯状带” ,FCM分析显示特征性的凋亡峰。胸腺细胞凋亡于LM (5× 10 5CFU )感染后 8h出现 ,48h达高峰。胸腺细胞凋亡百分率随LM感染剂量增加而增高。LM诱导小鼠胸腺细胞凋亡中p5 3、Bax及c myc基因表达产物明显增加 ,而Bcl 2基因表达产物水平无明显改变。提示LM以时间和剂量依赖方式诱导小鼠胸腺细胞凋亡 ,p5 3、Bax及c myc基因在LM诱导小鼠胸腺细胞凋亡的基因调控中起重要作用。

To study the apoptosis of thymocytes and its gene regulation induced by Listeria monocytogenesis (LM),the apoptosis of thymocytes and the expression levels of gene products in apoptotic cells were examined by DNA electrophoresis and flow cytometry (FCM) analysis. Experimental results showed that LM could induce apoptosis of murine thymocytes with typical 'ladder pattern' in agarose electrophoresis,and the FCM analysis showed typical apoptotic peak. The percentage of apoptosis increased from 8 hours after infection and reached its highest level at 48 hour,correlating with the increase of infecting dosage of LM. The dynamic observations displayed that the expressions of gene products of p53. Bax,and c-myc increased significantly with no significant changes of Bcl-2 gene product. It suggests that LM can induce apoptosis of murine thymocytes in a dose and time dependent manner,and the p53,bax,and c-myc genes might play an important roles in the gene regulation of thymocyte apoptosis.