小剂量辐射对小鼠肿瘤转移的抑制作用

THE INHIBITORY EFFECT OF LOW DOSE RADIATION ON TUMOR METASTASIS IN MICE

采用 B16黑色素瘤血道转移及 Lewis肺癌自发转移两种模型研究小剂量辐射对小鼠肿瘤转移的影响。结果发现 ,接受 X线单次全身预照射各组 (2 5 ,5 0 ,75 ,10 0 m Gy)小鼠的 B16黑色素瘤血道肺转移结节数明显低于对照组 (P<0 .0 5～ 0 .0 1) ,以 75 m Gy组为最低。75 m Gy X线全身预照射组小鼠 Lewis肺癌自发肺转移率及转移结节数均低于对照组 (P<0 .0 5～ 0 .0 1)。全身照射后 2 4小时检测小鼠免疫功能 ,结果显示 ,与对照组相比 ,75 m Gy照射组小鼠胸腺及脾有核细胞数增多 (P<0 .0 2 ) ,脾细胞对 Con A刺激反应性增强 (P<0 .0 0 1) ,NK细胞和巨噬细胞活性明显提高 (P<0 .0 1)。上述结果提示 :小剂量 X线全身照射对小鼠肿瘤转移具有抑制作用 ;小剂量辐射增强机体的免疫功能可能是其抗肿瘤转移的重要机制之一。

The effect of low dose radiation on tumor metastasis in mice was investigated by using the models of B16 melanoma bloodtract pulmonary metastasis and Lewis lung carcinoma. The results were reported as follows: (1) The number of B16 melanoma pulmonary metastatic colonies of the mice pre-received different doses(25,50,75,100mGy) of whole body irradiation were lower than that of unirradiated control group mice (P<0.05～0.01), and the lowest number was found in 75mGy group mice. (2) The rate and colonial number of LLC spontaneous pulmonary metastasis of the mice in whole body pre-exposed to 75mGy X-ray was lower than that of unirradiated control group mice. (3) Mouse immune functions were tested at 24h after irradiation. As compared with those of unirradiated control group,the nucleate cell number of thymus and spleen, proliferation response of spleen lymphocytes to ConA,ND cell activity and macrophage function increased significantly(P<0.05～0.01) in the mice of 75mGy X-ray whole body irradiation group. Our results suggests that low dose X-ray whole body irradiation has inhibitory effect on tumor metastasis in mice;the augmentation of immune functions may be one of the main mechanism for this effect.