大负荷游泳运动后大鼠额叶神经元凋亡和线粒体形态变化及Drp1、Mfn2表达的研究

Research onthe Frontal Neurons Apoptosis of Rats and the Mitochondrial Morphology and Expression of Drp1,Mfn2 after Overload Swimming

目的:通过观察一次性大负荷游泳运动后线粒体形态结构以及线粒体融合分裂基因及蛋白表达的动态变化,探讨一次性大负荷游泳运动引起大鼠额叶神经元凋亡发生发展的可能机制。方法:72只雄性SD大鼠随机分为对照组(C组,n=18),一次性大负荷游泳运动组(E组,n=54),再根据运动后取材时间的不同将E组分为:即刻组(E0组,n=18);24h组(E24组,n=18);48h组(E48组,n=18)。C组常规饲养,E组进行一次性大负荷游泳运动,无负重游泳4小时。用透射电镜观察额叶神经元及神经元线粒体的形态结构;用TUNEL法检测细胞凋亡指数(AI);检测线粒体融合分裂基因Drp1、Mfn2 mRNA转录及蛋白表达水平。结果:检测发现E组大鼠大脑额叶神经元发生了细胞凋亡,E组各组大鼠AI显著性高于C组(P<0.01),E组各时间点AI比较为:E24>E0>E48,各组间差异均具有显著性(P<0.05)。一次性大负荷运动后各时间点Drp1和Mfn2 mRNA转录和蛋白表达均高于C组(P<0.05),其中E24组大鼠大脑额叶Drp1和Mfn2 mRNA转录和蛋白的表达最强(P<0.01);与E24组比较,E48组大鼠大脑额叶Drp1mRNA转录和蛋白的表达下调显著(P<0.05),而Mfn2 mRNA转录和蛋白的表达下调不明显(P>0.05)。结论:一次性大负荷游泳运动引起大鼠额叶神经元凋亡及神经元线粒体形态结构异常,该异常在运动后48h内呈现动态性变化,机体可能通过调节线粒体融合分裂基因Drp1、Mfn2表达,影响大鼠额叶线粒体的形态结构和功能,从而调控额叶神经元凋亡的发生和发展。

Objective：This study was designed to discuss the relationship between cell apoptosis of the frontal lobe in-duced by one-time overload exercise and the changes of mitochondrial morphology in rats,as well as the ex-pression of Drp1、Mfn2, which are associated with mitochondrial fusion and division. Methods：48 male SD rats were randomly divided into control group（group C, n =18）,one-time overload exercise group（group E,n=54）. Group E was divided again into different groups based on time（immediately,24h and 48h）,named group E0,E24 and E48, with 18 rats in each group. Group E： carried out one -time exhaustive swimming for 4 hours. The morphological structure of the loubusfromatis neurons and mitochondria were observed by using trans-mission electron microscopy, the apoptosis index （ AI） detected by TUNEL method, and the mRNA and protein level of Drp1 and Mfn2 detected. Results：the rats’ frontal lobe neurons and mitochondrial appeared irregular af-ter one-time overload exercise,but this exception returned to normal in 48hours. There was a significant re-duction of AI in group E, when compared with group C（ P 〈0. 01）. When compared with the AI at different time points in group E,we can see that E24〉E0〉E48（ P 〈0. 05）. The transcription and protein expression of Drp1 and Mfn2 were significantly increased after one-time exhaustive exercise, when compared with group C（ P 〈0. 05）. The Drp1 transcription and protein expression of group E48 decreased significantly （ P 〈0. 05）,and the Mfn2 transcription and protein expression decreased slighter （P〉0. 05）, when compared with group E24. Conclusion：Suggest that one-time overload movement cause an abnormal mitochondria morphology and induce cell apoptosis of the loubus fromatis. But in 48 hours tissue damage of the loubus fromatis can be re-duced, or even recovery. The expression of Drp1 and the loubus fromatis cell apoptosis induced by exhaustion exercise were closely related. However, the increased expression of Mfn2 could ameliorate the development of the loubus fromatis cells apoptosis caused by exhaustion movement.