The Effects Of Endurance And Resistance Exercise On The Extracellular Matrix Collagen Of Skeletal Muscle In Aging Mice

China is rapidly entering the stage of the aging of the population,and some people have even predicted negative population growth in 2025.The probability of Sarcopenia in the elderly is not low.The proliferation of Skeletal muscle stem cells is the key to prevent and treat muscle Sarcopenia.Skeletal muscle satellite in extracellular matrix,which microenvironment contains a large amount of collagen I,skeletal muscle satellite cells below the basement membrane,which main component is collagen IV,skeletal muscle satellite cells through the basement membrane required to complete the repair of damaged skeletal muscle.Aging will deteriorate the microenvironment of skeletal muscle satellite cells,The main changes in aging are reflected in the increase of collagen deposition,thickening and stiffness,which is not conducive to the repair of skeletal muscle.Matrix metalloproteinases can degrade collagen.Exercise can affect the expression of MMPs and Tissue inhibitor of metalloproteinases,thereby affecting collagen and altering the microenvironment of skeletal muscle satellite cells.Objective: The mice were 9 weeks of endurance and resistance exercise training,and then detect the expression level of TIMP-1,TIMP-2,MMP-2,MMP-9,Collagen I,Collagen IV in gastrocnemius of mice,to investigate the effects of endurance and resistance exercise on the levels of TIMP-1,TIMP-2,MMP-2,MMP-9,Collagen I,Collagen IV expression in gastrocnemius of mice.The study of the mechanism of changes may provides a reference for the promotion of skeletal muscle regeneration and the prevention and treatment of Sarcopenia.Methods: The number of Balb/C male mice was 18,10 month old and 31.2-31.5g.They were randomly divided into group C(quiet control group),group A(endurance exercise group)and group R(anti resistance exercise group),6 in each group.The mice in group A with a rate of 0.8km/h for 40 minutes on the treadmill endurance training,training 3 days a week,Monday,Wednesday,Friday training,training for 9 weeks;The mice in group R of pyramid weight-bearing ladder training,training 3 days a week,Monday,Wednesday,Friday training,on the day of training,there were 5 groups,the first group was three times,the second group was two times,the third group was once,the fourth groups were two times,fifth groups were three times,the rest 120 s was between groups,the rest 60 s was between times,training for 9 weeks.The load is,the first week of the first group of 0% weight,second group of 20% weight,third group of 40% weight,fourth group of 20% weight,fifth group of 0% weight;second week of the first group of 20% weight,second group of 30% weight,third group of 60% weight,fourth group of 30% weight,fifth group of 20% weight;third week of the first group of 30% weight,second groups of 40% weight,third group of 80% weight,fourth group of 40% weight,fifth group of 30% weight;fourth week of the first group of 40% weight,second group of 50% weight,third group of 100% weight,fourth group of 50% weight,fifth group of 0% weight;Fifth week of the first group of 50% weight,second group of 60% weight,third group of 120% weight,fourth group of 60% weight,fifth group of 50% weight;sixth week of the first group of 60% weight,second group of 70% weight,third group of 140% weight,fourth group of 70% weight,fifth group of 60% weight;The seventh,eighth,ninth week training program is same as the sixth week training program.The mice in group C did not exert any intervention.All mice were weighed every time before each training.Once a week,all mice were tested for the grip strength of the limbs,each mouse was measured three times,taking the mean.Sirius red staining was used to detect Collagen volume fraction of gastrocnemius;Collagen IV area was detected by immunofluorescence;Western Blotting was used to detect protein level Collagen I,Collagen IV,MMP-2,MMP-9,TIMP-1,TIMP-2 protein level of the gastrocnemius;RT-PCR was used to detect the TIMP-1 and TIMP-2mRNA levels of the gastrocnemius.Results:(1)There was no difference in weight,gastrocnemius wet weight and gastrocnemius mass of the three groups of mice.Compared with grip strength of the limbs of group C mice,group R mice significantly increased grip strength of the limbs in ninth week?The grip strength of the limbs of group A mice increased significantly in the sixth and seventh week,and no difference was found after seventh week.(2)Compared with the collagen deposition in gastrocnemius of the C group,the collagen deposition in the gastrocnemius of the R group mice was significantly reduced.There was no significant differences among the three groups of gastrocnemius collagen volume fraction.Compared with the Collagen IV area of the gastrocnemius in group C mice,the Collagen IV area of the gastrocnemius in the group R mice was significantly reduced.(3)Compared with the protein level of Collagen I and Collagen IV in the gastrocnemius of group C mice,the level of Collagen I and Collagen IV protein level in the gastrocnemius of the group R mice decreased significantly.Compared with the level of MMP-2 and MMP-9 protein level in the gastrocnemius of group C mice,the protein level of MMP-2 and MMP-9 in the gastrocnemius of group R mice was significantly higher than that in the gastrocnemius of the group C mice.Compared with the TIMP-1 protein level of gastrocnemius in the group C mice,the TIMP-1 protein level of the gastrocnemius in the gastrocnemius of the group A mice was significantly reduced,and the TIMP-1 protein level in the gastrocnemius of the group R mice was significantly reduced too.Compared with the protein level of TIMP-2 in the gastrocnemius of group C mice,the TIMP-2 protein level in the gastrocnemius of the group R mice was significantly lower.Compared with TIMP-1mRNA level in the gastrocnemius of group C mice,the TIMP-1mRNA level in the gastrocnemius of the group R mice decreased significantly.Compared with the TIMP-1mRNA level in the gastrocnemius of group C mice,the TIMP-2mRNA level in the gastrocnemius of the group R mice decreased significantly.Conclusions:(1)Under the experimental model,resistance exercise can effectively improve the malignant change of skeletal muscle extracellular matrix in aging mice,significantly improve the grip strength and improve the physiological function of aging mice.(2)Under the experimental model,resistance exercise can effectively regulate the protein level of MMPs and TIMPs,and has a positive effect on collagen in the skeletal muscle extracellular matrix of aging mice.(3)Under the experimental model,the effect of resistance movement to improve the collagen status of the extracellular matrix of skeletal muscle in aging mice is better than that of endurance exercise.