自发性细胞凋亡及bcl-2和bax基因与鼻咽癌放射敏感性关系的探讨

Relationship between spontaneous apoptosis,bcl-2 and bax genes and radiosensitivity of nasopharyngeal carcinoma

目的探讨自发性细胞凋亡及其相关基因bcl-2和bax与鼻咽癌放射敏感性的关系。方法采用TdT酶介导的生物素化dUTP缺口末端标记技术(terminal oxynucleotidyl transferase medi-ated dUTP biotin nick end labeling,TUNEL)和免疫组化法,分别检测51例放疗前的鼻咽癌活检组织中自发性凋亡指数(spontaneous apoptotic index,SAI)和bcl-2、bax基因的表达。结果鼻咽癌活检组织均检测到细胞凋亡,SAI平均为31.19±33.83;SAI与bcl-2和bax表达均无明显相关性,但与bcl-2/bax比率呈负相关(P<0.05);SAI与鼻咽癌放射敏感性明显相关,完全消退组比残留组SAI高(P<0.05);bcl-2的表达与鼻咽癌放射敏感性呈负相关(P<0.05),而bax的表达与鼻咽癌放射敏感性无关(P>0.05);bcl-2/bax的比率与鼻咽癌放射敏感性呈负相关(P<0.05)。结论SAI、bcl-2和bcl-2/bax的比率是反映鼻咽癌放射敏感性和预测鼻咽癌放疗效果的重要指标,而bax不能单独作为判断鼻咽癌放射敏感性的指标。

Objective To investigate the relationship between spontaneous apoptosis, apoptosis-related genes bcl-2, bax and the radiosensitivity of nasopharyngeal carcinoma （NPC）. Methods Terminal oxynucleotidyl transferase mediated dUTP biotin nick end labeling（TUNEL） and immunohistochemical method were used to detect the spontaneous apoptotic index（SAI） and expression of bcl-2 and bax protein respectively in 51 biopsy specimens prior to radiotherapy of NPC. Results The levels of spontaneous apoptosis were observed in all specimens evaluated, the mean SAI was 31.19±33.83. The SAI was not correlated to the expression of bcl-2 protein or bax protein, but was negatively correlated to bcl-2/bax ratio （ P 〈 0. 05 ）. The SAI was obviously correlated with the radiosensitivity of NPC. The SAI in the group without residual tumor was significantly higher than that in the group with residual tumor （P 〈 0.05）. The bcl-2 protein expression was negatively correlated with the radiosensitivity of NPC （P 〈 0. 05 ）, while the bax protein expression was not correlated with the radiosensitivity of NPC （ P 〉 0. 05 ）. There was a negative correlation between bcl-2/bax ratio and the radiosensitivity of NPC （P 〈 0. 05）. Conclusion The SAI, bcl-2 protein and the bcl-2/bax ratio are the important parameters reflecting the radiosensitivity and predicting the radiotherapeutic efficacy of NPC, while the bax protein can not be taken as an independent parameter to predict radiosensitivity of NPC.