抗氧化剂对二氧化硫诱导的大鼠心脏线粒体损伤的缓解作用

Antioxidants alleviated sulfur dioxide-induced mitochondrial damage in rat hearts

采用Wistar大鼠作为模型进行整体动物染毒,SO_2组动式吸入SO_2(7mg/m^3)28d,每天4h;SO_2+NALC(N-乙酰半胱氨酸)组吸入同样条件的SO_2,且自SO_2染毒之日起隔天腹腔注射50mg/kg b.w.NALC,对照组吸入新鲜空气并注射生理盐水.采用荧光定量PCR技术检测心脏组织中氧化磷酸化复合体亚基CO1和ATP6以及核转录因子PGC1-α、NRF1、TFAM的mRNA转录水平;并采用Western blot技术检测3种线粒体调控基因的蛋白表达.结果发现,在吸入SO_2后,核转录因子PGC1-α、NRF1、TFAM的mRNA转录和蛋白表达水平显著降低,并且2种亚基CO1和ATP6的mRNA转录水平也显著下降,而抗氧化剂NALC处理能够明显缓解3种核转录因子及2种复合体亚基表达水平的下降.提示SO_2暴露通过下调PGC1-α、NRF1、TFAM表达来影响线粒体DNA的转录,干扰氧化磷酸化重要组分的合成,该过程发生机制可能与自由基的产生相关,而抗氧化剂的使用可有效缓解SO_2诱导的心脏线粒体损伤作用.

Male Wistar rats were exposed to SO2（7 mg/m^3） for 28 days, 4 hours per day in SO2 group. Rats in SO2＋NALC group were exposed to SO2 and NALC（50 mg/kg b.w., i.p.） every other day, which was dissolved in saline. Rats in control group were exposed to filtered air and saline. The m RNA levels of complexes IV and V subunits（CO1ATP6） and three mitochondrial transcript factors（PGC1-α, NRF1, TFAM） were analyzed by real-time RT-PCR after exposure. And the protein levels of the above three mitochondrial transcript factors were detected by Western blot. The results showed that the m RNA and protein expression levels of PGC1-α, NRF1 and TFAM were decreased significantly after SO2 inhalation, combined with the down-regulations of CO1ATP6 on m RNA levels. But NALC could alleviate the depressions of these genes. It indicated that SO2 exposure could impact the transcription of mitochondria DNA through PGC1-α-NRF1-TFAM down-regulation, interfere the synthesis of important components of oxidative phosphorylation. The mechanism might be related to the production of free radicals. Antioxidants could be used to alleviate sulfur dioxide-induced mitochondrial damage in rat hearts.