冷冻治疗对G422胶质瘤细胞凋亡的影响

Apoptosis Induced by Freezing in G422 Glioma and Mechanism

目的 研究局部冷冻对G422胶质瘤细胞凋亡及其调控机制的影响。方法 建立小鼠脑胶质瘤动物模型,于冷冻治疗后6、12、24、48、72 h留取标本,用光镜、末端标记法(TUNEL)、DNA凝胶电泳检测细胞凋亡,用免疫组化技术检测凋亡相关基因bcl-2、bax的表达产物。结果G422胶质瘤经冷冻治疗后,冷冻灶中心区呈坏死改变,冷冻周边区出现凋亡的形态学改变,DNA呈“梯状”降解,冷冻后各时间点凋亡细胞数目均明显多于对照组(P<0.01)。bax表达阳性细胞数也多于对照组(P<0.05),而冷冻对bcl-2表达无明显影响。结论 除坏死外,诱导细胞凋亡可能是冷冻杀伤胶质瘤细胞的另一重要机制;这种细胞凋亡可能是通过上调bax基因的表达来实现。

Objective To investigate the effects of cryotherapy on apoptosis in mouse G422 glioma and to explore its mechanism. Methods Mouse experimental models of glioma was established. The specimens were taken at 6, 12, 24, 48, 72 h after freezing. Microscopy, TUNEL staining and DNA gel electrophore-sis were made to detect apoptosis. The expression of bcl-2 and bax was detected by immunohistochemical assay. Results Morphological changes of apoptosis appeared in the periphery of freezing in mouse G422 glioma. DNA fragmentation showed a 'ladder' break. The number of apoptotic cells was significantly increased as compared with that in the control group (P<0. 01). The changes of necrosis appeared in the core of cryotherapy. Meanwhile, the number of bax positive cells was significantly increased as compared with that in the control group (P<0. 05) at all time points. There was no effect of cryotherapy on the expression of bcl-2. Conclusion Besides necrosis, the activation of apoptotic cell death may be one of the other important mechanisms in cryotherapy of glioma with freezing possibly by up-regulation of bax.