^(252)锎中子放疗对宫颈癌细胞凋亡和增殖的影响

The effect of ^(252)Cf neutron radiation on apoptosis and proliferation of uterine cervical carcinoma cells

目的探讨252锎中子射线治疗宫颈癌的机制。方法应用TUNEL法、免疫组化检测宫颈鳞癌放疗前后的细胞凋亡、凋亡相关基因bcl2、bax及PCNA表达变化。结果20例患者宫颈癌细胞凋亡阳性率和凋亡指数(AI)分别由放疗前的35%和(4.22±4.14)%增加至放疗后的85%和(34.64±24.36)%,差异有显著性(P均<0.01)。放疗前后bcl2表达无明显变化(P>0.05),且与凋亡无明显相关(P>0.05)。bax表达阳性率和平均标记指数分别由放疗前的25%和(8.35±3.06)%增加至放疗后的80%和(16.43±6.05)%,差异有显著性(P<0.01),且放疗后bax表达与凋亡呈正相关(r=0.8520,P<0.01)。PCNA标记指数放疗后为(24.18±5.37)%,比放疗前的(48.67±5.62)%下降明显,两者之间差异有显著性(P<0.01)。结论252锎中子射线治疗宫颈癌的机制不仅在于诱导细胞凋亡,而且抑制了肿瘤细胞增殖活性。bax表达是252锎中子射线诱导细胞凋亡的途径之一,其机制可能与bcl2/bax间的平衡改变有关。

Objective To study the apoptosis changes and expression of apoptosis -related gene bcl-2,bax and PCNA which represent the proliferation characteristic of the tumor cells on the cervical carcinoma cells before and after 252 Cf neutron brachytherapy.Methods The apoptosis and expression of bcl-2,bax gene,PCNA were detected on twenty cervical carcinoma cases before and after 252 Cf neutron brachytherapy by TUNEL (TdT-mediated dUTP nick end labeling) and immunohistochemical methods.Results Before radiotherapy, the the mean AI and apoptotic positivity rate were (4.22±4.14)% and 35%, and after radiotherapy, they increase to (34.64±24.36)% and 85% respectively. Both the indexes had significant increase (P<0.01). The positivity rates of bax and the mean labeling indexes were 25% and (8.35±3.06)% before radiotherapy, and after radiotherapy, they increase to 80% and (16.43±6.05)% respectively. Both the indexes had significant increase (P<0.01). A positive correlation was found between the expression of bax and apoptosis after radiotherapy (r=0.8520,P<0.01),but no relation was found between bcl-2 and apoptosis. After radiotherapy, mean PI (PCNA labeling indexes) decresed from (48.67±5.62)% to (24.18± 5.37)%, and the difference was significant (P<0.01).Conclusion The mechanism of 252 Cf neutron brachytherapy are not only to induce apoptosis but also to inhibit proliferation of tumor cell. Bax protein is associtated with apoptosis induced by 252 Cf neutron brachytherapy and that the change of the balance between bax and bcl-2 modulate apoptosis.