不同城市PM2.5对易感小鼠线粒体损伤的影响

Effects of PM2.5 from different cities on mitochondrial injury in susceptible mice

采集太原市冬季大气细颗粒物(PM2.5),选取4周、4月、10月龄C57BL/6雌性小鼠,采用咽后壁滴注的方法用3mg/kg(体重)PM2.5暴露4周.此外,分别采集太原市、北京市、杭州市和广州市4个城市的冬季PM2.5,将10月龄小鼠暴露其中.采用荧光定量PCR技术检测心脏组织中细胞色素C氧化酶亚基Ⅰ(co1)、Ⅳ(co4)和ATP合酶(ATP6)以及核转录因子pgc-1α、nrf1和tfam的mRNA转录水平.结果发现,太原市PM2.5暴露后,10月龄小鼠心脏组织中co1、co4和ATP6以及核转录因子pgc-1α、nrf1和tfam的mRNA水平与对照组相比均显著升高.但4周和4月龄小鼠中上述基因表达则未见明显差异.10月龄小鼠暴露于不同城市PM2.5后,杭州PM2.5暴露可引起小鼠心脏组织中co1、co4、ATP6、pgc-1α、tfam的mRNA表达上升.北京PM2.5暴露可引起小鼠心脏组织中co1、ATP6和tfam的mRNA表达显著上升;广州PM2.5暴露则未见上述任何基因表达的显著改变.研究表明,太原市PM2.5对易感小鼠心脏线粒体氧化磷酸化的影响最大,其次是杭州市和北京市,而广州市的影响最小.

In this study,two separated experiments about the effects of fine particulate matter(PM2.5) on mitochondrial injury in susceptible mice were comied out.In first set of experiments,winter fine particulate matter(PM2.5) was collected in Taiyuan City and the C57 BL/6 female mice at 4 weeks,4 months and 10 months old were exposed to 3 mg/kg(body weight) PM2.5 for 4 weeks by oropharyngeal instillation.Second,the winter PM2.5 were collected from Taiyuan,Beijing,Hangzhou,and Guangzhou and exposed to 10 months old mice similarly.The results from the first set of experiments showed that the mRNA levels of Cytochrome c oxidase subunits Ⅰ(co1),Ⅳ(co4) and ATP synthase(ATP6) and nuclear transcription factors pgc-1α,nrf1 and tfam in cardiac tissues were detected by real-time PCR.The mRNA levels of co1,co4,ATP6 and nuclear transcription factors pgc-1α,nrf1 and tfam were significantly elevated in hearts of 10-month-old but not in those of 4-week-old and 4-month-old mice after Taiyuan PM2.5 exposure.In the second set of experiments,when 10-month-old mice were exposed to PM2.5 from different cities,the exposure of PM2.5 from Hangzhou could increase the mRNA expression of co1,co4,ATP6,pgc-1α and tfam in the hearts of mice.Exposure to PM2.5 from Beijing can increase the mRNA expression of co1,ATP6 and tfam in mouse hearts.PM2.5 from Guangzhou exposure did not cause any of the above changes in gene expression.PM2.5 from Taiyuan has the greatest impact on mitochondrial oxidative phosphorylation in susceptible mice,followed by from Hangzhou and Beijing,while PM2.5 from Guangzhou has the least impact.