Effects Of Endurance Training On Skeletal Muscle MEF2mRNA,GLUT4mRNA Of Rats

Human skeletal muscle is the most important tissue,with the great plasticity. after long-term regular physical exercises,its functions and configuration obtain a greater extent of adaptive changes.Long-term regular exercises can significantly increase the number and size of skeletal muscle cells,and the number of mitochondria in cells;also can improve related metabolic enzyme activity and strengthen the ability of fatty acid oxidation,Glucose Transporters and glycogen synthesis.Glucose is an important raw material for the maintenance of cellular energy metabolism and life activities,it is not allowed to come in or out the cell freely,It needs the help of the membrane glucose transporter protein(glucose transporters.GLUT)to enter the intracellular,exercises and muscle movements will increase the protein content and GLUT4 translocation.At present,it is not very clear about the mechanism how exercises and muscle contraction cause the increase of GLUT4 protein translocation. Some Studies abroad report that cell=Ca²⁺concentration increase when exercises and AMPK,p38MAPK could lead to the activation of GLUT4 gene transcription,but the specific mechanism must be further studied,especially the detailed mechanism of calcium and calmodulin kinase(CaMK)in the exercises.Therefore,in-depth study of exercise-induced increase in GLUT4 translocation mechanisms has great significance,This may provide a theoretical basis for the treatment and prevention of insulin resistance-related diseases(such as type 2 diabetes),and on this basis an effective drug treatment and exercise prescription may be developed.Method:The experiment use 32 8-week-old male Sprague-Dawley rats,weighing 200±12.8g.They were randomly divided into 4 groups,control group(group C,n= 8);Medium intensity exercise group(group D,n=8);high-intensity exercise group (Group E,n=8);Medium intensity and inhibitor group(group Dy,n=8).rats exercise groups begin training after a week adaptive training by swimming training. From the second week the rats of Dy group are treated by 1%inhibitor of CaMKIV inhibitor KN-62 for irrigation stomach daily by incremental swimming training,five days a week for eight weeks and weigh them on every Mondays.Test blood glucose (enzymatic oxidation)and calcium(MTB)after 8 weeks;Test MEF2mRNA and GLUT4mRNA expression level in right gastronomies' muscle by the method of RT-PCR.Result:Compared with the control group,eight-week swimming training can make moderate group and excessive group lower blood glucose,but the blood glucose in over-training rats are lower than them in the moderate group,leading to hypoglycemia. Blood calcium in Excessive training group is far greater than it in the quiet group. compared with the moderate group without inhibitor,the GLUT4mRNA and MEF2mRNA expression significantly downward after eight-week swimming training.Conclusion:Long-term moderate exercises training can lower blood glucose,but excessive training may injury body,CaMKIV inhibitors may block the expression of GLUT4,so that blood glucose can not be delivered to the cells,so that elevated blood glucose concentrations.High-intensity exercises cause great consumption of calcium, breaking calcium balance between the bones and blood.long-term Medium and over-training increase rats' MEF2mRNA and GLUT4mRNA expression significantly,while the moderate intensity inhibitor group reduce significantly.the CaMKIV may be an upper signal moleculor,MEF2 may participate in sports-mediated GLUT4mRNA expression.This study found no differences of GLUT4mRNA expression between the two intensities.The results suggested that there may be:Sports -＞CaMKIV-＞MEF2-＞GLUT4 relationship or signal pathway.