中文摘要：

目的： 探讨Period2（Per2）基因对紫外线损伤NIH3T3细胞的影响。方法： 将Per2基因插入pcDNA 3.1,构建Per2基因的真核表达质粒,采用脂质体包裹法转导入NIH3T3细胞内，以紫外灯照射Per2基因过表达（pcDNA 3.1-Per2）的NIH3T3细胞、pcDNA 3.1空白组（pcDNA 3.1-vector）细胞和空白对照组细胞;通过流式细胞术和克隆形成试验检测稳定转染Per2阳性表达的NIH3T3细胞的凋亡、生长情况;采用单细胞凝胶电泳技术检测Per2过表达对DNA损伤后修复的影响。结果： 紫外线照射后Per2阳性表达的NIH3T3细胞较其对照组细胞增殖速度快、凋亡率减少,单细胞凝胶电泳实验表明紫外线照射后,各组细胞均表现出明显的DNA损伤,但是pcDNA 3.1-Per2转染组均较pcDNA 3.1-vector及空白对照组细胞的彗星细胞出现率和拖尾细胞DNA迁移长度低。结论： 节律基因Per2能抑制紫外线对细胞的损伤,其机制可能与Per2促进DNA修复作用有关。

英文摘要：

Objective To investigate the effect of circadian gene Period2（Per2） on NIH3T3 cell damaged by ultraviolet. Methods The Per2 expressing vector （pcDNA 3. 1-Per2） was transfected into NIH3T3 cells（pcDNA 3.1-Per2 transfected with pcDNA 3.1-Per2, and pcDNA 3.1-vector transfected with pcDNA 3.1-vector） by liposome. They were irradiated with ultraviolet light. Expression of Per2 in the NIH3T3 cells was tested by immunohistochemistry and flowcytometry,while proliferation and apoptosis were examined by colony formation assay and flowcytometry. Single cell gel electrophoresis （SCGE） was used to test the damage and repair pattern of DNA. Results As compared with the control cells, NIH3T3 cells transfected with pcDNA 3.1-Per2 showed high proliferation and low apoptosis after ultraviolet irradiation. SCGE test also showed that the rate of comet cell and the length of DNA migration was lower in pcDNA 3.1-Per2 transfected cells than that in control cells, though all groups exhibited apparent damage of DNA. Conclusion Per2 may have protective effect against ultraviolet damage to DNA. The mechanism may be related to the enhancement of DNA repair by Per2.