低水平电离辐射单次或分割照射法的抗肿瘤效应比较

Comparison of anti-tumor effects of low level ionizing radiation with single or fractionated irradiation method

目的 比较低水平电离辐射 (L L IR)单次与分割照射的抗肿瘤效应。方法 选用 C5 7BL/ 6和 ICR品系小鼠分别移植 L ewis肺癌和 S180肉瘤细胞 ,2 4h后再分别接受 7.5 c Gy单次照射和分割照射 (1.5 c Gy× 5 d) ;然后观察 2 0 d抑瘤率、脾 NK细胞活性、T淋巴细胞表面 CD4、CD8水平的变化以及荷瘤鼠的平均寿命。结果 单次与分割照射对 L ewis肺癌的抑瘤率分别为 40 .34%和 5 1.19% ,对 S180肉瘤为 34.2 6 %和 30 .98% ;脾 NK细胞活性照后 1～ 4d升高 ;CD4、CD8水平及 CD4/ CD8比值均有不同程度增高 ;荷瘤鼠的生命延长率分别为 8.45 %和 8.84%。结论 本实验采用的低水平单次或分割照射对 L ewis肺癌和 S180肉瘤均有明显的抑瘤效果 ,能显著增强荷瘤机体的免疫机能以及延长荷瘤鼠的平均寿命。经比较 ,两种照射方式在肿瘤生长抑制和免疫刺激作用等方面差异无显著性 (P>0 .0 5 )。

Objective To compare the anti tumor effects of low level ionizing radiation with single or fractionated irradiation method. Methods Lewis cells and S180 sarcoma were transplanted to C57BL/6 and ICR mice and were respectively irradiated with single dose(7 5 cGy) or fractionated dose(1 5 cGy×5 d) 24 h later. Then the tumor inhibitory rate, splenic NK cell activity, CD4 and CD8 levels on T lymphocyte surface, and the average longevity of tumor bearing mice at 20 d were observed. Results The tumor inhibitory rates of Lewis cancer with single or fractionated irradiation were 40 34% and 51 19% respectively, and that of S180 sarcome were 34 26% and 30 98%. Splenic NK cell activity was elevated in 1 to 4 days after irradiation. CD4 and CD8 levels and the ratio of CD4/CD8 all increased to some different extent after irradiation. And the life prolongation rates in S180 tumor bearing mice were 8 45% and 8 84% respectively. Conclusions Low dose and low dose rate radiation have obvious anti tumor effects in mice with Lewis cancer and S180 sarcoma, and they enhance immunological function and prolong average longevity of the tumor bearing mice. But there were no statistical difference( P >0 05) in tumor growth inhibition and immunological function stimulation between the single and the fractionated irradiation.