中文摘要：

目的 探讨电离辐射诱导人淋巴细胞线粒体COX Ⅰ、COXⅡ和COXⅢ基因表达的改变.方法 用1、3、5、8和10 Gy 60Co γ射线分别照射指数增长期的人淋巴细胞永生化细胞株,8 h后用逆转录PCR（RT-PCR）和实时荧光定量PCR（Real-time PCR）方法检测COX Ⅰ、COXⅡ和COXⅢ基因在mRNA水平上的表达;流式细胞术检测其在蛋白水平上的表达;比色法检测COX活性,来分析辐射诱导线粒体COX Ⅰ、COXⅡ和COXⅢ基因表达改变的量效关系.同时,以5 Gy γ射线照射人淋巴细胞,分别于照后不同时间（0.5、4、8、12、24、48和72 h）,同样通过上述指标来分析3种线粒体基因的表达变化,观察其时效关系.结果 在mRNA水平上,线粒体COX Ⅰ、COXⅡ和COXⅢ基因表达总体上调.COX Ⅰ和COXⅢ基因在0～3 Gy剂量范围内具有量效关系,而COXⅡ基因在0～8 Gy剂量范围内具有量效关系（FCOXⅠ=116.62,FCOXⅡ=17.89,FCOXⅢ=8.20,P＜0.05）;5 Gy照后4 h左右COXⅡ和COXⅢ基因表达上调最显著,而COX Ⅰ基因持续低表达（FCOXⅠ=31.99,FCOXⅡ=19.47,FCOXⅢ=20.64,P＜0.05）.在蛋白水平上,不同剂量照射后,COX Ⅰ和COXⅡ蛋白表达先下调后上调,COXⅢ蛋白表达下调（FCOXⅠ=16.96,FCOXⅡ=32.5,FCOXⅢ=6.51,P＜0.05）;5 Gy照后4 h,COX Ⅰ蛋白表达明显增强,达到8 h后出现COXⅡ蛋白表达显著上调,而COXⅢ蛋白表达普遍下调（FCOXⅠ=14.68,FCOXⅡ=17.18,FCOXⅢ=2.52,P＜0.05）.此外,受照后COX活性普遍降低.结论 电离辐射可以诱导人淋巴细胞线粒体COX Ⅰ、COXⅡ和COXⅢ基因表达的改变,基因表达总体增强的同时,COX活性普遍降低.

英文摘要：

Objective To explore the changes of human mitochondrial COX Ⅰ , COX Ⅱ and COX Ⅲ genes expression induced by ionizing irradiation. Methods Changes of human COX genes expression were detected by RT-PCR and Real-time PCR 8 h after the irradiation in human lymphoblastoid cell lines,which were exposed to 1-10 Gy60Co γ-rays. The protein levels were detected by flow cytometry and the COX activity was measured by colorimetry. The dose-effect relationships between the expression changes of the genes and the doses were established. The changes of these genes expression were also analyzed at different post-radiation time-points between 0. 5 h and 72 h after irradiation of 5 Gy in order to explore the time-effect. Results The expression of 3 genes at mRNA level was up-regulated. A good dose-effect relationship was showed for COXⅠ and COX Ⅲ at dose range of 0-3 Gy and 0-8 Gy for COX Ⅱ （ F COXⅠ=116. 62, FCOXⅡ = 17. 89, FCOXⅢ = 8.20, P ＜ 0. 05）. For the time-effect after irradiation, the gene expression levels of COX Ⅱ and COX Ⅲ genes were up-regulated and the peak change occurred at 4 h after irradiation. For COX Ⅰ gene, the mRNA expression levels were down-regulated during 0.5-72 h（ FCOXⅠ =31.99, FCOXⅡ = 19.47, FCOXⅢ = 20. 64, P ＜0. 05 ）. At the protein level, the levels of COX Ⅰ and COX Ⅱ were lowered in lower doses and enhanced in higher doses, and the levels of COX Ⅲ were decreased at all dose levels （FCOX Ⅰ = 16.96, FCOXⅡ = 32.5, FCOXⅢ = 6. 51, P ＜ 0. 05 ）. The protein levels of COX Ⅰ and COX Ⅱ were enhanced during 4-72 h and 8-72 h respectively after 5 Gy irradiation （ FCOX Ⅰ = 14.68,FCOXⅡ = 17. 18, FCOXⅢ =2. 52, P ＜0. 05）. The activities of COX were lowered at different dose levels and different time-points. Conclusions Ionizing radiation might induce the changes in mitochondrial COX Ⅰ,COX Ⅱ and COX Ⅲ gene expression, and lead to the reduction of the COX activities.