The Control Of S100A1 On Mitochondria Function In Cardiomyocytes Oxidative Stress Injury By Exhaustive Exercise

A lot of oxygen free radicals from human body during carrying out exhaustive exercise could result in the occurrence of cardiovascular disease.Therefore it is important to study the functional control of mitochondria in cardiocytes under oxidative stress by exhaustive exercise for preventing cardiocyte from injury.S100A1 is a kind of calcium-binding protein.It can increase myocardial contractility,control vascular function and also stimulate activity of ATP synthetase.S100A1 can affect function of mitochondria through binding ANT（adenine nucleotide translocator,ANT）.Whether S100A1 control the function of mitochondria through interaction with ANT after cardiocytes injury by oxidative stress remains unclear.Our aim is to investigate the expression of S100A1 and ANT in cardiocytes and the change of mitochondria function by animal model under oxidative stress by exhaustive exercise and oxidative stress cardiocytes in vitro model.We will reveal how S100A1 affect mitochondria function in oxidative stress cardiocytes by applying exogenous intervention and gene transfection,which maybe further support new concept for protecting cardiocytes from injury after exhaustive exercises.The following is the mainly results:1 The expression of S100A1 and ANT protein in myocardium of rats injured by exercise oxidative stressMale Wistar rats were random divided into the normal control group（NC）and the exhaustion exercise group（EI）.After ten days of loading-increasing treadmill running,the rats in both NC and EI were immediately decapitated for colleting blood and cardiovascular tissue.Then detection of biochemical and pathological indexes examination of rats myocardium.The results showed that the activity of ROS and CK were significantly higher than those in the control group and SOD activity and GSH-PX content were significantly lower than those in the control group after exhaustive exercise.It is suggested that the exhaustive exercise in rats can cause oxidative stress injury of cardiac myocytes and the antioxidation ability of the body is reduced.HE results showed the structure of cardiovascular tissue in NC group is integrity and no pathological changes.And the myocardium of EI group emerged vacuolar degeneration or interstitial edema and so on.Electron microscope results showed:in normal control group the structure of the myocardium was approximately normal,Capillary patency and the myocardium fibers were arranged neatly,the mitochondria were dense and the myocardium had no obvious exudation.While in the exhaustion exercise group,visible myocardial fiber rupture,mitochondrialcristae swelling,focalnecrosis.Immunohistochemistry results showed that S100A1 and ANT protein were evenly distributed in the tissues of the normal control group,and the S100A1 and ANT protein in the tissue of oxidative stress injury group were significantly reduced.Western-blot results showed that the content of S100A1 and ANT protein in myocardial tissue decreased in the exhaustion exercise group compared with normal control group.2 The effect and regulation of S100A1 protein on mitochondrial function of myocardial injury induced by oxidative stressThe myocardial cells were treated with H₂O₂ at a concentration of 1mM for 12 h to establish an oxidative stress injury model.The results showed that H₂O₂ could lead to oxidative stress injury,myocardial cell viability decreased,and induced partial myocardial cell apoptosis.Exogenous S100A1 protein has the effect of reversing myocardial oxidative stress injury,improving cells viability and inhibiting cells apoptosis.The results of RT-PCR showed that the mRNA of S100A1,ANT,PGC-1αand Tfam was significantly decreased in myocardial cells injured by oxidative stress,and the mRNA of ANT,Tfam and PGC-1αwere significantly increased after the addition of exogenous S100A1.The results of Western-blot showed that the expression of S100A1,ANT,Tfam and PGC-1αwas decreased in myocardial cells injured by oxidative stress.The levels of S100A1,ANT,Tfam and PGC-1αin myocardium were increased after the addition of S100A1 protein.In order to investigate the effect and regulation of S100A1 on myocardial mitochondrial function induced by oxidative stress,we used Si-RNAS100A1 to silence the S100A1 gene in cells.The results of RT-PCR and Western-Blot showed that the gene and protein expressions of S100A1,ANT,PGC-1αand Tfam were decreased after knockdown S100A1.It is suggested that S100A1 protein may play an important role in the function of mitochondria of myocardium injured by interacting with ANT and further affecting the expression of PGC-1αand nuclear transcription factor Tfam.These results suggest that the effect and regulation of S100A1 on myocardial mitochondrial function induced by oxidative stress may be mediated through the interaction between S100A1 protein and mitochondrial target ANT and mediate the exchange of cytosolic ADP and mitochondrial ATP.In summary,exhaustive exercise can cause oxidative stress injury and mitochondrial dysfunction in rat cardiomyocytes,and the expression of S100A1 and ANT protein is decreased in the myocardium of exhaustive exercise-induced oxidative stress injury.The H9c2 cardiomyocyte oxidative stress model was established.After exogenous S100A1 protein was administered,the survival rate of H9c2 cardiomyocytes increased,and the gene and protein expressions of ANT,PGC-1αand Tfam also increased.After knockout of S100A1,the gene and protein expression levels of S100A1,ANT,PGC-1αand Tfam in H9c2cardiomyocytes were reduced.ANT protein has the effect of promoting PGC-1αexpression.And the increase of PGC-1αlevel will also increase the expression of nuclear transcription factor Tfam and further promote mitochondrial function improvement,which may be one of the regulatory mechanisms of S100A1 protein on the mitochondrial function of oxidative stress.