缺氧对大鼠大脑皮质细胞色素氧化酶亚基Ⅰ、Ⅳ表达协同性的影响  

Effects of hypoxic exposure on coordinative expression of cytochrome oxidase subunitsⅠand Ⅳ in rat cerebral cortex

作　　者：谭小玲[1] 柳君泽[1] 曹利飞[1] 邓忠才[1] 李英和[1] 

机构地区：[1]第三军医大学高原军事医学系病理生理学与高原生理学教研室,全军高原生理和高原病研究重点实验室,重庆400038

出　　处：《生理学报》2002年第6期519-524,共6页Acta Physiologica Sinica

基　　金：ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina (No 30 0 70 2 90 )andagrantfromtheTenth Five YearProgramoftheChinesePeople'sLiberationArmy (No 0 1MB10 9)

摘　　要：本文探讨缺氧对细胞色素氧化酶 (cytochromeoxidase ,COX ,即complexⅣ )的mtDNA和nDNA编码亚基Ⅰ、Ⅳ表达及其协同性的影响。实验用成年雄性Wistar大鼠随机分为对照组、缺氧 2、5、15和 3 0d组。缺氧大鼠于低压舱内模拟海拔 5 0 0 0m连续减压。对照组大鼠于舱外同时喂养 (舱外海拔高度为 3 0 0m)。用半定量逆转录 PCR法测定大脑皮质COXⅠ、ⅣmRNA量 ,用Westernblot分析大脑皮质线粒体COXⅠ、Ⅳ蛋白量 ,以两个亚基的蛋白量、mRNA量的比值反映亚基表达的协同性。结果显示 ,缺氧 2、5d ,COXⅠmRNA增加 ,缺氧 15、3 0d时下降至对照水平。缺氧 2、5和 15d时 ,COXⅣmRNA显著增加 ,缺氧 3 0d时降低 ,与对照组差异非常显著。COXⅣ、ⅠmRNA比值在缺氧 15d时最高 ,其它各缺氧组与对照组的差异无显著意义。各组COXⅠ、Ⅳ蛋白量及其比值均无显著差异。上述结果表明 ,缺氧可影响COXⅠ、ⅣmRNA的表达及其协同性 ,但对蛋白的表达及其协同性没有显著影响 ,提示转录后调节是缺氧过程中线粒体内COXⅠ。This study was intended to evaluate the effects of hypoxic exposure on gene expression and coordination of cytochrome oxidase (COX) subunitsⅠ (COX Ⅰ) and Ⅳ (COX Ⅳ) encoded by mtDNA and nDNA respectively in rat cerebral cortex. Male Wistar rats were exposed to hypoxia in a hypobaric chamber simulating high altitude at 5000 m for 2, 5, 15 and 30 d. Control rats were fed outside the hypobaric chamber (the height was 300 m above sea level). Rats were sacrificed and mitochondria from cerebral cortex were isolated by differential centrifugation at each time point. COXⅠand COX Ⅳ proteins in isolated rat cerebral cortex mitochondria were detected by Western blot analysis and mRNA in the cerebral cortex by RT-PCR. The ratios of protein and mRNA were used to estimate the coordinative expression of two subunits. The results showed that COXⅠ mRNA increased significantly at 2 and 5 d, and decreased to the control level at 15 and 30 d; COX Ⅳ mRNA remarkably increased at 2, 5 and 15 d, and dropped below the control level at 30 d. The mRNA ratio of COX Ⅳ to COXⅠ reached a peak at 15 d, but showed no differences between other time points. The Western blot analysis of COXⅠand COX Ⅳ in isolated rat cerebral cortex mitochondria showed no obvious changes during hypoxic exposure. Our findings demonstrate that hypoxia can affect mRNA expression of COX Ⅰand COX Ⅳ and their coordination,while protein expression of both subunits are stable and coordinative. This study suggests that the expres- sion of COX Ⅰand COX Ⅳ proteins during hypoxic exposure is coordinately regulated by post-transcriptional mechanisms.

关 键 词：缺氧 大鼠 大脑皮质细胞 色素氧化酶亚基Ⅰ 协同性 细胞色素氧化酶Ⅳ 基因表达 

分 类 号：Q42[生物学—神经生物学]