不同强度力竭运动模型大鼠肝细胞凋亡及相关变化

Effects of various exhaustive exercise on hepatic apoptosis in rats

背景:国内外不少实验证明,不同运动方式容易造成肝损伤,导致不同程度的肝细胞凋亡,其具体机制尚不明确。目的:建立不同强度力竭运动模型,观察运动后大鼠肝细胞凋亡和肝糖元、NO、钙浓度变化。设计、时间及地点:随机对照动物实验,超微结构观察,于2004-01/2006-12在湖南师范大学体育学院运动人体科学实验室、中南大学组胚实验室完成。材料:30只8周龄雄性SD大鼠,体质量(219.2±19.5)g,根据Berdford运动模型将大鼠以随机数字表法分为对照组,中等强度、大强度力竭运动组,每组10只。方法:运动组先进行3d的适应性跑台训练,速度为10m/min,坡度为0°。休息3d后,中等强度力竭运动组初始速度为10m/min,持续12min,逐渐增加运动负荷,达到速度为19.3m/min,持续到力竭。大强度力竭运动组初始速度为26.8m/min,持续到力竭。共30d,1次/d。对照组不进行运动训练。主要观察指标:运动后即刻取肝组织检测肝糖元、NO和Ca2+及肝细胞凋亡情况。结果:30只大鼠全部进入结果分析。不同强度力竭运动组大鼠都完成了运动,整个运动过程中未出现拒跑现象,中等强度力竭运动组力竭运动时间为(234.60±60.05)min,大强度力竭运动组力竭运动时间为(92.40±34.61)min。与对照组比较,两种强度力竭运动后,大鼠肝组织肝糖元含量、NO浓度均下降,线粒体Ca2+浓度、肝细胞凋亡指数均升高(P<0.05,P<0.01),中等强度力竭运动组效果更明显(P<0.05)。结论:中、大强度力竭运动均可导致大鼠肝细胞凋亡,肝糖元含量、NO浓度下降,线粒体Ca2+浓度升高,中等强度力竭运动效果更为显著,可能与力竭运动时间长有关。

BACKGROUND： Previous studies demonstrated that exercise modes easily cause hepatic injury and result in hepatic apoptosis. However, the mechanisms remain unclear. OBJECTIVE： To observe the hepatic apoptosis, changes of hepatic glycogen, NO, and calcium levels following establishing various exhaustive exercise models. DESIGN, TIME AND SETTING： The randomized, controlled, animal experiment of ultrastructure observation was performed at the Physical Education School of Hunan Normal University, and Department of Histology and Embryology, Central South University, from January 2004 to December 2006. MATERIALS： Thirty male Sprague Dawley rats, aged 8 weeks, weighing （219.2±19.5）g, were randomly divided into control, middle intensity exercise and high intensity exercise groups according to Berdford models, with 10 animals in each group. METHODS： Rats in the exercise group were performed 3 days treadmill training with speed of 10 m/min, in running platform with 0° followed by 3 days rest. After that, rats in the middle intensity exercise group were training with initial velocity of 10 m/min for 12 minutes, and than gradually increased exercise load to 19.3 m/min, until rats were exhausted. In the high intensity exercise groups, the initial velocity was 26.8 m/min, until rats were exhausted. The training was performed once per day for 30 successive days. There was no exercise training in the control group. MAIN OUTCOME MEASURES： The levels of hepatic glycogen, NO, Ca2＋, and hepatic apoptosis were measured after exercise. RESULTS： Totally 30 rats were included in the final analysis. All rats finished exercise without resistance. The exhaustive exercise time in the middle intensity exercise group was （234.60±60.05） min, which was （92.40±34.61） min in the high intensity exercise group. Compared to the control group, the contents of hepatic glycogen and NO were decreased, while Ca^2＋ level and hepatic apoptosis index were increased in 2 exercise groups （P 〈 0.05, P 〈 0.01）, in particular notable in the middle intensity exercise group （P 〈 0.05）. CONCLUSION： Both middle and high intensity exhaustive exercise can lead to hepatic apoptosis, which may be the great accumulation of Ca^2＋ in mitochondrion and the lower contents of liver glycogen and NO content. The changes may be associated with exhaustive exercise time.