不同跑步速度训练大鼠肌肉细胞凋亡的初步实验研究

本研究旨在观察运动训练中肌肉细胞是否会出现细胞凋亡 ,并为进一步开展细胞凋亡在运动训练导致运动疲劳与运动损伤中的应用研究而建立动物速度训练模型。雄性 2月龄SD大鼠随机分为 6组 ,在经历两个月的训练后 ,分别按 0m/min(安静 )、1 8m/min、3 0m/min、42m/min、5 4m/min和 66m/min的速度在跑台上跑步 3min ,即刻断头取股四头肌 ,做冰冻切片处理。股四头肌冰冻切片进行能对凋亡细胞特异染色的脱氧核糖核苷酸末端转移酶介导的缺口末端标记 (TUNEL)法染色和组织学之苏木精—伊红(HE)染色。在荧光显微镜下观察TUNEL染色的股四头肌冰冻切片 ,发现在运动各组均有散在的标记细胞核 ;在HE染色片中 ,可以观察到与TUNEL染色呈阳性核之肌细胞的显微结构未发生明显变化 ,但出现细胞核染色质浓缩、靠近核膜、核膜增厚等现象。这些结果表明在运动训练中出现了肌肉细胞凋亡的现象。此外 ,在本实验设计的 5个速度组中 ,凋亡的肌细胞出现率略呈随跑速增加而增高的趋势。用膜脂质过氧化的最终产物丙二醛 (MDA)作为指标 ,检测氧自由基的作用 ,发现各运动组MDA值均比安静组略有增加 ,各运动组之间MDA值接近 ,但无统计学差异 ;另一方面 ,MDA值与细胞凋亡出现率一样有随运动强度增加而增高的趋势。结果提示 ,运动训练可以

Preliminary Study on Apoptosis in Skeletal Muscle in Rat Trained at Different Speeds

To investigate whether or not apoptosis exists in skeletal muscle after exercise, and to develop a model of rats running on treadmill for further applied research on apoptosis in exercise, 2 month old male Sprague-Dawley rats were divided into 6 groups randomly: sedentary group (0 m/min), 18 m/min group, 30 m/min group, 42 m/min group, 54 m/min group and 66 m/min group. After 2 month adaptive training, the rats in trained groups run on treadmill 3 minute at 18 m/min, 30 m/min, 42 m/min, 54 m/min and 66 m/min, respectively. The rats were instantly sacrificed by decollation after running, and quadriceps femoris muscle was removed. The muscle frozen sections cut by cryostat were stained for terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labeling (TUNEL), which stained apoptostic cell specifically, and for hematoxylin-eosin (HE) in histology. In fluorescence microscope, the muscle frozen sections stained for the TUNEL appeared scattering labeled nuclei in each training group. In sections stained for HE, however, the structure of cell whose nucleus was labeled for the TUNEL did not changed, while the cell appeared nuclear chromatin condensation, becoming packed against nuclear membrane, and nuclear membrane thickening. These results showed that the muscle cell apoptosis existed after exercise. In addition, it appeared that the appearance of apoptosis increased with increasing of running speed. Malondialdehyde (MDA), an index of membrane lipid peroxidation, increased after training without significant difference as compared with sedentary, and there was no significant difference in MDA among running groups. More over, it appeared that the appearance of MDA increased with increasing training intensity, which was similar to the muscle cell apoptosis. These results suggested that exercise was able to bring about muscle cell apoptosis, and free oxygen radical play an important role in muscle cell apoptosis induced by exercise.