运动预处理影响线粒体形态变化以及相关因子表达干预力竭运动后大鼠额叶细胞凋亡

Exercise Preconditioning Ameliorates the Cell Apoptosis in Lobus Frontalis of Rats after Acute Exhaustive Exercise

目的:从线粒体形态结构变化以及检测相关调控因子的表达,探讨运动预处理干预力竭运动后大鼠额叶损伤的可能机制。方法:36只雄性SD大鼠随机分为对照组(C组,n=12)、力竭运动组(EE组,n=12)、运动预处理组(EP组,n=12)。EP组进行持续4周的无负重60 min/day游泳训练后,EE组和EP组进行无负重一次性力竭游泳运动。运动结束后24 h,采用灌注取材和直接断头取材。用HE染色和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),分析各组大鼠额叶神经元凋亡情况;用Real-Time PCR和Western blotting检测线粒体分裂和融合相关因子——Drp1和Mfn2m RNA和蛋白表达水平。结果:一次性力竭运动引起了大鼠额叶神经元及神经元线粒体形态结构的异常。TUNEL法检测发现EE组大鼠大脑额叶神经元AI较EP组显著增加(P<0.05)。一次性力竭运动引起了Drp1和Mfn2 m RNA转录和蛋白的高表达,其中,EP组大鼠大脑额叶Mfn2表达强度较EE组显著升高(P<0.05),EP组大鼠大脑额叶Drp1表达强度较EE组显著下降(P<0.05)。结论:Drp1的表达水平与力竭运动后额叶细胞凋亡程度密切相关,而Mfn2的表达增加能够减轻力竭运动引起的脑细胞凋亡水平。4周的游泳训练运动预处理,能够相对减少Drp1表达而上调Mfn2基因表达,影响大鼠额叶线粒体的形态结构变化,增强脑对运动性缺血缺氧的耐受力,减轻一次性力竭运动造成的大鼠额叶缺血缺氧性损伤。

Objectives To explore the effect of exercise preconditioning on the acute exhaustive exercise- induced ischemia anoxic injury in lobus frontalis of rats. Methods 36 male SD rats were randomly and equally divided into sedentary control group （C）,exhaustive exercise group （EE）and exercise preconditioning group （EP）. Rats in group EP carried out 4-week swimming,60 min per day. Thereafter,rats in groups EP and EE underwent an acute exhaustive swimming. The morphological structure and mitochondria of neurons in lobus frontalis were observed through HE staining and transmission electron microscopy,and the apoptosis index （AI） ,mRNA and protein level of Drpl and Mfn2 were detected by TUNEL method,real time RT-PCR and Western blot respectively. Results The neurons in lobus frontalis and their mitochondria became irregular after exhaustive exercise. There was a significant reduction of AI in group EP as compared with group EE（P〈0.05）. The transcription and protein expression of Drpl and Mfn2 increased significantly in both groups EE and EP after exhaustive exercise. Whereas,the transcription and protein expression of Drpl decreased （P〈0.05）,and the transcription and protein expression of Mfn2 increased （P〈0.05）in group EP as compared with EE group. Conclusion 4-week exercise preconditioning enhances the tolerance ability of rats against toward the exhaustive exercise-induced ischemic injury in lobus frontalis by decreasing the expression of Drpl and increasing the expression of Mfn2.