ABSTRACT
BACKGROUND: Apoptosis in the skeletal muscle leads to a variety of skeletal muscle diseases, but there are ideal no therapies so far. OBJECTIVE: To analyze the effects of different intensities of exercises on the morphology and apoptosis of the skeletal muscle in rats. METHODS: Thirty healthy male 3-month-old Sprague-Dawley rats were randomly allocated into three groups (n=10 per group): control group (no swimming), aerobic exercise and high-intensity exercise groups. The rats in the exercise groups underwent swimming for consecutive 10 weeks. Then, the gastrocnemius muscle was isolated from all rats under anesthesia. The morphology and cell apoptosis were detected by hematoxylin-eosin staining and TUNEL test. At the same time, the levels of superoxide dismutase and malondialdehyde in skeletal muscle tissue were tested and the correlation of malondialdehyde with integrated optical density (IOD) was analyzed. RESULTS AND CONCLUSION: The results of hematoxylin-eosin staining showed that the muscle fibers were in disorder arrangement with obscure structure in the high-intensity exercise group. Compared with the control group, the content of malondialdehyde was increased in the exercise groups, especially in the aerobic exercise group (P < 0.05). The level of superoxide dismutase in the high-intensity exercise group was significantly lower than that in the aerobic exercise group (P < 0.05). The results of TUNEL test showed that the IOD values in the high-intensity exercise group were significantly higher than those in the aerobic exercise and control groups (P < 0.05). There was a positive correlation of malondialdehyde with IOD. These results indicate that the long-term and high-intensity exercise can increase the content of malondialdehyde in the skeletal muscle, resulting in an aggravation of fatigue. Aerobic exercise can obtain the adaptation of the skeletal muscle, but damage the morphology and structure of the skeletal muscle because of excessive exercise load, thus accelarating the cell apoptosis. With the exercise intensity increasing, the balance between malondialdehyde production and clearance is broken, and the IOD value is increased.
ABSTRACT
<p><b>OBJECTIVE</b>This study is to see the pathologic change of cardiac myocyte in Athlete's Heart, and explore the mechanism of the pathologic change.</p><p><b>METHODS</b>Fifteen male SD rats were separated randomly into control group (without any exercise), aerobic exercise group (Ae group, swimming for 75 min every day), and overloading exercise group (Oe group, swimming for 180 min with a loading of 5 percent of body weight every day). After 5 days per week for 12 weeks, swimming stopped, the rat hearts were prepared to specimens and examined under Transmission Electron Microscope.</p><p><b>RESULTS</b>The Ae group, the number and volume of mitochondria increased, and the membrane of mitochondria remained entire. Few of dense bodies were found in cytoplasm. The nucleus envelopes of expansion nucleus appear as dentition. These changes were considered as the adaptation to exercises. At the same time, some pathologic changes of the cardiac myocytes similar to senescence also appeared, such as mitochondria expanse, the crista disorder or disappearance, unclear mitochondria membrane, many dense bodies in cytoplasm, nucleus disfiguration and chromatin collection at edge.</p><p><b>CONCLUSION</b>After exercise training, some pathologic changes of cardiac myocyte also occur with physiological changes. With the raise of exercise intension, the pathologic changes become more obvious, even appearance of cardiac myocyte death.</p>
Subject(s)
Animals , Male , Rats , Cardiomegaly , Pathology , Exercise Tolerance , Microscopy, Electron , Mitochondria, Heart , Myocardial Contraction , Myocytes, Cardiac , Rats, Sprague-Dawley , SwimmingABSTRACT
<p><b>OBJECTIVE</b>To see the change of capillary of heart in Athlete's Heart, so that to discover the mechanism of pathologic change.</p><p><b>METHOD</b>18 male SD rats were separated randomly into control group (without any exercise), aerobic exercise group (swimming for 75 min every day), and overload group (swimming for 180 min with 5% weight of its body every day). After 5 days per week, 12 weeks, exercise training stopped and heart of rats were observed under Transmission Electron Microscope.</p><p><b>RESULTS</b>In aerobic exercise group, the capillary cavities in heart expand, the walls of capillary become thick; the number of mitochondrion increases; endothelium cells become active in growth. However, after overload exercise, the walls of capillary cockle and protuberances appear. The mitochondrion swell and the cristae become disorder. Most of endosomes expand and their number increases. The karyons become abnormity in shape and uniformity in electronic density, besides the nuclear envelope cockle. The basilar membranes become thick and unclear.</p><p><b>CONCLUSION</b>After exercise training, both physical and pathologic changes in heart capillary are found. In suitable exercises group, the capillaries change physically; the pathologic changes are becoming visible after overload exercise however.</p>