Experimental Study On Apoptosis Of Skeletal Muscle Of Rattles After Taking Exhausting Exercises

Experimental study on apoptosis of skeletal muscle of rattles after takingexhausting exercisesObjective To investigate the phenomenon of apoptosis in rats' muscle and the effect of antioxidizing vitamins(vitamin E and vitamin C) on skeletal muscles in rats which taking repeated exhausting run on the treadmill.Methods 50 SD male rats were divided randomly into five groups: control group(C), exhausting exercising group(E), vitamin E group(Ml), vitamin C group(M2) and vitamin E plus vitamin C group(M3). The exercising groups(E, Ml, M2, M3) took repeating exhausting run on the treadmill for 4 weeks. Inspect the body mass, exercise length and left quadriceps femoris net mass, the content of malonic acid and free calcium, the activity of SOD in rats' quadriceps femoris mitochondria. Observe the changes of the skeletal muscle cells' ultrastructure through the electron microscope(TEM). Apoptotic percentages of gastrocnemius muscle cells of rats were measured by flow cytometry(FCM) using Annexin V/PI double staining method. The express of the mRNA of a-actin and apoptosis-correlating genes, bcl-2 and bax, were detected by means of polymerase chain reaction(PCR).Results Take vitamin E alone or plus vitamin C orally could improve body mass, total exercise treadmill length and quadriceps femoris net mass of rats after having 4-week exhausting exercise on treadmill. There were not difference between rats taking vitamin C orally alone and E group on the three parameters. Ml, M2 and M3 groups' malonic acid(MDA) and free calcium content of quadriceps femoris were less than the control group. Ml, M2 and M3 groups' activity of SOD of quadriceps femoris mitochondria were more than the control group. Morphologic changes of early stage in apoptotic cell could be seen under electron microscope(TEM), such as the aggregation of chronosome, the expansion of nuclei cistern and the contraction of nucleus in the exercising muscles. The percentages of theapoptotic cells and the dead cells in every exercising groups' (except M3 group) rats' gastrocnemius muscle were more than the C group's, significantly. The percentages of the normal cells were decrease more or less in every exercising groups. There was no difference between the C group and the M3 group in these three type of cell. As to this, the percentages of E group and M2 group were lower than Ml group and M3 group, significantly. The express of the mRNA of a-actin of quadriceps femoris cells increased in every exercising groups' rats. The expresses were powerful in the M3 group. There was no difference between the E group and the M2 group. In the quadriceps femoris cells of rats of the Ml, M3 groups, the expresses of bcl-2 increased, the expresses of Bax decreased. There was no difference between the E group and the M2 group.Conclusions A high level of lipid peroxidation was observed in the working skeletal muscle which have taken 4 weeks repeated centrifugal contraction. Oxidative stress may be the main reason of the mitochondria' injury, moreover, lead to the death of muscle cells. The malfunction of the mitochondria maybe induce the apoptosis of muscle cells. The augment of express of the mRNA of a-actin perhaps is a motor modulation of the exercising animal. To various degrees, the antioxidant vitamins can protect the mitochondria of muscle cells, also promote the express of the anti-apoptosis genes and reduce the express of the auxo-apoptosis genes in muscle cells.Vitamin E can protect the mitochondria in skeletal muscle and improve the sports ability of the exhausting exercising rats on treadmill, vitamin C could enhance this effect. Take vitamin C alone can not sufficiently improve exercise ability of rats that taking repeated exhausting exercise.