喉鳞状细胞癌不同分割照射诱导凋亡研究

Effect of Fractionated Dose Irradiation on Apoptosis of Laryngeal Squanous Cell Carcionoma.

目的研究X线诱导人喉鳞状细胞癌Hep-2不同分割方案照射后,凋亡动力学变化、克隆生存率情况以及P53、PC-NA、Bcl-2表达。方法采用6MV直线加速器X线照射,FCAS检测不同分割方案、不同时间点凋亡率、细胞周期分布情况;用免疫组化SABC法观察P53、PCNA、Bcl-2表达。结果Hep-2受到单次剂量照射后,凋亡率在72小时达到峰值,以10GY最高为19.8%,最终净凋亡率从高至低依次为2.0GY组11.4%、3.5GY组7.8%、10.0GY组7.39%、5.0GY组6.11%,各组之间无统计学差异(P>0.05)。相对克隆生存率分别为2.0GY组80.0%、3.5GY组91.34%、5.0GY组74.28%、10.0GY组71.43%,各组与3.5GY组存在统计学差异(P<0.05)。各组中P53、PCNA、均表达阳性,Bcl-2表达阴性。结论从凋亡角度看,小剂量多分割照射可能使更多的肿瘤细胞以凋亡方式死亡;2.0GY组和10.0GY组在相对克隆生存率上无差异,提示在实体瘤的放射治疗中,凋亡的作用有限,Hep-2可能以坏死为其主要死亡形式。免疫组化染色表明Hep-2的P53基因发生突变,野生型P53基因的关卡作用可能不存在,而且具有较强的增殖活性。

Objective To investigate the apoptosis ,cloning survival rate and expressions of P53,PCNA,and Bcl-2 in laryngeal squamous cell carcinoma following various dose irradiaton. Methods Human laryngeal squamous cell carcinoma cell lines, Hep -2 was irradiated with 6MV linear accelerator, and cell cycle distribution in Hep -2 were determined by FCAS. The expressions of P53,PCNA and Bcl -2 were detected by immunohistochemical SABC technique. Results The apoptosis rate reached a peak at 72h after a single dose irradiation in Hep -2. The apoptosis rate was highttest （19.8%） after the irradiation with 10.0 GY. The final net apoptosis rate was 11.4% in 2.0 GY group, 7.8% in 3.5 GY group, 7.39% in 10.0 GY group and 6.11% in 5.0 GY group respectively. There was insignificant difference in the apoptosis rate among various dose groups（ P 〉0.05）. Relative clonging survival rate was 80.0% in 2. GY group,91.34% in 3.5 GY group,74.28% in 5.0 GY group and 71.43% in 10.0 GY group respectively. There was significant difference in the relative cloning survival rate between 3.5 GY group and each of the other groups（ P 〈0.05）. The expressions of P53 and PCNA was postive, and expression of Bcl-2 was negative in all the groups. Conclusions The low dose and multi -fractionation irradiation can induced more cells apoptosis in Hep -2. They are suggested that in the solid tumour,irradiation induced apoptosis was limited and Hep-2 may died mainly in nercosis affter the radiotherapy. They also are suggested that after the irradtion the mulation of mtp53 gene may occur in Hep-2, checkpoint of wtp53 maybe disappear and Hep-2 has more proliferative activity.