The basic research about gene-radiation therapy using DNase II gene

我们制作了放射抵抗性肿瘤和放射敏感性肿瘤小鼠。综合考虑肿瘤的粘性和肿瘤的宽度，确定能使小鼠产生适当凋亡的辐射剂量。每只小鼠接受10 Gy γ射线照射。用TUNEL法、DNA梯状条带法和流式细胞仪检测照射前后各小鼠细胞凋亡的发生情况，未发现照射前后细胞凋亡的发生有明显差异。用SDS-PAGE和western blot方法检测了照射前后小鼠DNA酶Ⅱ的表达情况，后者的表达量是前者的5倍。因此，辐射敏感性与体内DNA酶II水平不相关。另一方面，我们利用体内转染试剂，将DNase Ⅱ基因转染到放射抵抗性肿瘤小鼠体内，用TUNEL法、DNA梯状条带法和流式细胞仪检测转染前后和照射前后细胞凋亡的发生。转染成功。但转染后辐射凋亡无明显改变。因此，DNA酶II的转染很难改变辐射敏感性。

We made mice with radiation-resistant tumor and radiation-sensitive tumor. We considered stickiness and width of tumor and decided the radiation dose which made a proper apoptosis on the mice. We irradiated 10Gy gamma ray to each mice. We checked the occurrence of apoptosis on each mice before and after the irradiation with TUNNEL method, ladder of DNA and flowcytometry Then we did not detect the apparent difference of occurrence of apoptosis between the former and the latter. We also checked the occurrence of DNase II on each mice before and after the irradiation with SDS-PAGE and the western blot method, and the occurrence of DNase II on the latter was five times as the occurrence of DNase II on the former. Therefore the radiation sensitivity cannot correlate with DNase II level in vivo. This fact differs from its in vitro.On the other hand, we expressed DNase II gene to the mice with radiation-resistant tumor using in vivo transfection regent, and checked the occurrence of apoptosis before and after the transfection and the irradiation with TUNNEL method, ladder of DNA and flowcytometry. The transfection was successful. However, the radiation apoptosis did not change by the transfection. Therefore it is difficult that the transfection of DNase II makes a change of radiation sensitivity.