不同浓度氧对放射所致肿瘤细胞凋亡影响的研究

目的：探讨不同浓度氧对放射所致肿瘤细胞凋亡的影响。方法：实验分为空气组、高氧组及低氧组。肿瘤细胞为LA-795小鼠自发性肺腺癌细胞，接种于T-739纯系小鼠右后肢皮下，待荷瘤肢直径达10mm时照射22Gy，HE染色及TdT末端标记法检测肿瘤细胞凋亡指数。结果：照射后LA-795肿瘤细胞发生细胞凋亡，在6h达高峰，以后逐渐下降。高氧可增加照射所诱导的凋亡；低氧吸入0.5min后照射对肿瘤细胞凋亡影响不大，其水平与空气组相近。结论：吸入高浓度氧后改吸低浓度氧的同时合并放疗的方法能够提高肿瘤细胞放射敏感性，这一现象可通过其增加肿瘤细胞凋亡的方式来解释。氧对细胞凋亡影响的作用机理尚待进一步研究。

Effects of oxygen concentration on radiation-induced apoptosis

Objective To investigate the effects of oxygen at different concentrations on radiation induced apoptosis. Methods LA 795 spontaneous tumor cells inoculated subcutaneously into inbred T 739 mice were exposed to 22 Gy X rays under aerobic, carbogen(95%O 2 +5%CO 2),and hypoxic(10%O 2 +85% N 2 +5%CO 2)conditions, and radiation induced apoptosis was detected by HE stain and terminal deoxynucleotidyl transferase mediated dUTP nick end labeling(TUNEL)technique. Results Apoptotic index(AI)detected by HE stain and TUNEL was higher in carbogen group than that in aerobic group and hypoxic group, while there was no difference between aerobic group and hypoxic group. Conclusion Carbogen inhalation can enhance the effect of radiation induced apoptosis in LA 795 tumor cells. A half minute hypoxic exposure before irradiation has no effect on apoptosis.;