中文摘要：

为探讨低剂量电离辐射在C57BL／6J小鼠肿瘤基因-放疗方案中的作用，对荷瘤小鼠采用不同的治疗方案（单纯多次大剂量局部照射、单次大剂量局部照射加多次低剂量全身照射、pEgr-IL18-B7．1基因联合放疗），观察其对肿瘤重量、全肺表面转移结节数以及肿瘤间质微血管密度的影响。结果显示，采用单纯放疗和基因-放疗与对照组相比均能显著降低肿瘤重量、全肺表面转移结节数和肿瘤间质微血管密度；单纯放疗方案中应用单次大剂量局部照射加多次低剂量全身照射与单纯多次大剂量局部照射相比，在降低治疗剂量的同时，能达到相近似的抑瘤效果。在基因-放疗方案中，基因导入联合单次大剂量局部照射后加多次低剂量全身照射的治疗效果明显优于联合应用常规多次大剂量局部照射。提示低剂量电离辐射可以通过减轻肿瘤负荷、减少肿瘤远处转移和抑制肿瘤间质血管形成，增强基因-放疗方案的抑瘤作用。

英文摘要：

In order to approach the effect of low dose ionizing radiation in the protocol of gene-radiotherapy on tumor-bearing C57BL/6J mice, the weight of tumors, the number of lung metastatic nodes and the intratumoral micro-vessel density of tumor-bearing mice with different treatments （e. g. repeated high dose local irradiation alone, single high dose local irradiation in combination with repeated low dose whole-body irradiation and pEgr-IL18-B7.1 gene-radiotherapy） were detected, respectively. The results showed that both radiotherapy and gene-radio therapy could significantly decrease the weight of tumors, number of lung metastatic nodes and intratumoral micro-vessel density of mice compared with control group. As compared with repeated high dose local irradiation alone, single high dose local irradiation in combination with repeated low dose wholebody irradiation showed similar therapeutic efficacy in the protocol of conventional radiotherapy, and even more significant inhibition of tumor growth under gene-radiotherapy. It was demonstrated that low dose whole-body irradiation superimposed upon a local high dose could enhance the anti-tumor effect in the protocol of gene-radiotherapy by means of abatement of tumor load, reduction of tumor metastasis and inhibition of intratumoral vasifaction.