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目的探究热习服是否能够对湿热环境下进行中高强度运动大鼠的大脑皮质和心肌线粒体结构与功能起保护作用,并探讨其保护机制。方法 40只SD大鼠通过负重力竭实验剔除游泳时间过短和过长的大鼠各4只,剩余32只大鼠随机分成常温自由活动(RA)组、常温运动(RE)组、高温自由活动(HA)组和高温运动(HE)组,每组8只。RA和HA组大鼠分别置于常温[(24±1)℃]和高温[(32±1)℃]条件下自由活动2h/d;RE和HE组大鼠分别置于常温[(24±1)℃]和高温[(32±1)℃]条件下的饲养笼内自由活动1h/d后,在动物跑步机上匀速跑步1h/d(坡度为0°,速度为14m/min);连续训练14d建立热习服大鼠模型。建模后第3天开始,各组大鼠在湿热环境下中高强度运动30min。测量并记录湿热环境下中高强度运动前、后大鼠体质量丢失率、肛温,采用放射免疫法测量血浆去甲肾上腺素(NE)、血管加压素(AVP)和皮质醇(Cort)含量,透射电镜观察运动后大鼠大脑皮质和心肌线粒体的超微结构,ELISA法检测ATP合成酶和活性氧(ROS)含量,总抗氧化能力测试(ABTS)法检测总抗氧化能力。结果 HE组大鼠在湿热环境下中高强度运动后体质量丢失率高于RA组(P<0.01);HE组大鼠运动前、后肛温以及肛温升高幅度均低于RA、RE和HA组(P<0.05,P<0.01)。HE组大鼠运动后血浆中Cort含量低于RA、RE和HA组(P<0.05,P<0.01),大脑皮质和心肌线粒体中ATP合成酶和组织中总抗氧化能力高于RA、RE和HA组(P<0.01),ROS含量低于RA、RE和HA组(P<0.01)。HE组大鼠大脑皮质中线粒体和突触结构以及心肌中线粒体、Z线和横小管的结构优于RA、RE和HA组。结论热习服训练能够增强线粒体氧化呼吸功能、降低细胞的氧化应激水平和血浆中Cort含量,从而保护湿热环境下中高强度运动后大鼠的大脑皮质神经元和心肌细胞线粒体结构。
Objective To investigate whether heat acclimation can protect the structure and function of mitochondria in the cerebral cortex and myocardium under moderate to high-intensity exercise in hot and humid environment and to explore its protective mechanism. Methods Forty SD rats were divided into 4 groups: rats in swimming group with short swimming time and too long swimming time. The remaining 32 rats were randomly divided into normal temperature free movement (RA) group, normal temperature exercise group (RE) Activity (HA) group and high temperature exercise (HE) group, 8 in each group. Rats in RA and HA groups were allowed to freely move for 2 hours at room temperature [(24 ± 1) ℃] and high temperature [(32 ± 1) ℃] respectively; (1 ° C) and high temperature [(32 ± 1) ° C] for 1 h / d in a cage, and run uniformly on an animal treadmill for 1 h / d (gradient 0 °, speed 14 m / min) Training 14d to establish a heat rat model. On the 3rd day after modeling, rats in each group were exercised for 30 minutes in high and middle intensity in hot and humid environment. The body weight loss and rectal temperature were measured and recorded before and after exercise in high and low intensity exercise in hot and humid environment, and the levels of plasma norepinephrine (NE), vasopressin (AVP) and cortisol (Cort) were measured by radioimmunoassay The ultrastructure of cerebral cortex and myocardium mitochondria after exercise were observed by transmission electron microscopy. The levels of ATP synthase and reactive oxygen species (ROS) were detected by ELISA. The total antioxidant capacity (ABTS) was measured by ELISA. Results The weight loss rate of HE group was higher than that of RA group (P <0.01) in hot and humid environment. The increase of rectal temperature and rectal temperature before and after exercise in HE group were lower than those in RA, RE and HA group (P <0.05, P <0.01). The levels of Cort in plasma of rats in HE group were lower than those in RA, RE and HA groups (P <0.05, P <0.01). The total antioxidant capacity of ATP synthase and tissue in cerebral cortex and myocardial mitochondria was higher than that in RA, RE and HA groups HA group (P <0.01), ROS content was lower than that of RA, RE and HA groups (P <0.01). The structure of mitochondria and synapse in the cerebral cortex and the structure of mitochondria, Z line and lateral tubule in myocardium of HE group were better than that of RA, RE and HA group. Conclusion Heat acclimation training can enhance mitochondrial oxidative and respiratory function, reduce cellular oxidative stress and Cort content in plasma, and thus protect the mitochondrial structure of cortical neurons and cardiomyocytes in rats under moderate and high intensity exercise in hot and humid environment.