Different Forms Of Training Induced The Chang Of IL-15, MyoD And TNF-α In Mouse Skeletal Muscle

Skeletal muscle is the most abundant tissue in the human body accounting for 50% of the total bodymass. It is not only the major site of metabolic activity but it is also the largest protein reservoir, and playing a central role in nitrogen flow during some disease states. In essence, the maintenance of skeletal muscle mass is the result of the dynamic balance between muscle protein synthesis and muscle protein degradation. Over the years, a large body of evidence has suggested that in many disease states or unfavorable environmental conditions, skeletal muscle mass could be markedly reduced, a condition that may have devastating health consequences. In contrast, some forms of physical activity such as resistance exercise, can produce large increases in skeletal muscle mass. The early adaptive changes in skeletal muscle during increased loading are. probably also due to enhanced translation of existing mRNAs with such increases being significant enough to increase protein production after overloading. Likewise,the adaptive responses to exercise marke changes in some cytokines,including Interleukin-15(IL-15),Tumor necrosis factor-α(TNF-α) and The myogenic differentiation factor D (MyoD),etc.These cytokines play an important in the regulation of skeletal muscle. Intriguingly, the type of exercise stimuli governs the intricate balance of which signalling pathways are turned on or off, thereby providing for a regulation of different outcomes. This suggests a differential regulation of signalling by the type of exercise and the possibility of different outcomes, implying that pretranslational regulation takes place in response to exercise.To distinguish the respective potential of different type exercise training on Interleukin-15(IL-15),Tumor necrosis factor-α(TNF-α)and The myogenic differentiation factor D (MyoD) genes expression in the skeletal muscle of adult C57BL/6 mice, exercise programs of endurance training(treadimill running exercise), resistance exercise(ladder climbing) and mixing type training(combined treadimill running and ladder climbing) were found in the study to assess the impact of different type exercise training on skeletal muscle. Methods:32 two-month-old male C57BL/6 mices were randomly distributed into four groups:sedentary(C, n=8), endurance training(E, n=8), resistance exercise(R, n=8), mixing type training(M,n=8). After 28 weeks exercise intervening, quantitative Real-time PCR method is used to detect IL-15, TNF-αand MyoD mRNA expression in Tibialis anterior muscles. Results:1) Compared with the control group,Endurance training increased IL-15 and MyoD mRNA expression in skeletal muscle,but not significantly. Endurance training decreased TNF-αmRNA expression significantly.2) Compared with the control group,Resistance training significantly increased IL-15 and MyoDmRNA expression in the skeletal muscle,but decreased TNF-α. mRNA expression not significantly.3) Compared with the control group,Mixing type training had no significant influence on any gene.Conclusion:(1) The IL-15,MyoD and TNF-αmRNA in the skeletal muscle of trained mice had a significant change which indicated the adaption of skeletal muscle to training was closely related.(2) There was a different change of the IL-15,MyoD and TNF-αmRNA due to different kind of training,which inicate the adaption of skeletal muscle to different training maybe because of the change of specific gene.(3) The maintaintion of training to the quality of skeletal muscle may be the result of the interaction of different cytokines induced by training.