Effect Of Long-term Endurance Training On Cardiac Muscle Oxidative Stress And Autophagy Related Factor Expression

Objective:The purpose of this study is to establish a long term endurance training-oxidative stress-cell autophagy model,at the level of cardiac muscle cells:1.To study the effects of long term endurance training on autophagy in myocardial cells.2.To investigate the relationship between autophagy and oxidative stress in long term high intensity exercise.Methods:Select 48 SD rats were grouped to control group(C),moderate intensity group(M,15.2m / min speed of 5 ° slope)and high instensity group(H,28 m / min speed of 10 ° slope)with 16 animals in each group.Respectively does 8 weeks,and 16 weeks treadmill training.Training 5 days/weeks,1h/day.After each period of training,24 rats(8 rats in each group)were anesthetized and detected by echocardiography.Blood taken from abdominal aorta was used for the detection of oxidative stress factor(MDA,SOD)and myocardial injury factor c Tn I.Take the apex 1mm3 pieces for transmission electron microscope to observe the extent of autophagy.Cut the left ventricular wall,after HE staining to observe the myocardial morphology.RT-PCR,Western Blot to detect autophagy-related genes Beclin1,LC3,and p62 m RNA and protein expression of rat cardiomyocytes.Data using SPSS19.0 statistical software processing,p<0.05 has significant difference,p<0.01 has a very significant difference.Results:1)Changes in heart weight index: 16 weeks of H group HWI was significantly lower than C group(p<0.05).2)Changes in echocardiographic results: 8 weeks of M group EF was significantly higher than C group(p<0.05);16 weeks H group EF was lower than C group(p<0.05).3)Changes of oxidative stress index: 8 weeks of H group MDA was significantly higher than C group(p<0.05),16 weeks of H group MDA was very significantly higher than C group(p<0.01),8 weeks and 16 weeks H group MDA has a very significantly higher than M group(p<0.05);8 weeks of M group SOD was significantly higher than C group(p<0.05),8 weeks and 16 weeks H group SOD has a very significantly lower than C group(p<0.01)and M group(p<0.01);8 weeks M group,the ratio of SOD / MDA was higher than C group(p<0.05),8 weeks and 16 weeks H group SOD / MDA has a very significantly lower than M group(p<0.01)and C group(p<0.05).4)Changes of myocardial injury factors: 8 weeks and 16 weeks H group c Tn I was significantly higher than that of C group and M group(p<0.05).5)Myocardial tissue morphological changes: C group,myocardial cells arranged in neat rows,dense,clear cross striations,less extracellular matrix;M group,the cardiac cells arranged in a little disorder,the size of myocardial cells,cell gap widened,transverse striations,part of the muscle fiber fracture;H group,the cardiac arrangement disorderly,mast cell volume,enlarged nuclei,the transverse striation disappeared,intercellular space increased,muscle fiber fracture and 16 weeks of H group muscle fibers damaged the most serious.6)Morphologic changes of myocardial cells: C group myocardial cells arranged in neat,light and dark with clear,Z line complete,intercalated disc closely connected,desmosome;M group myocardial cells arranged slightly disordered mitochondrial compensatory hyperplasia,occasionally bilayer membrane structure;H group myofibrils fracture missing,intercalated disk is not continuous,mitochondria increased aggregation,morphological variation,mitochondria disappeared,increased electron density,two-layer membrane structure aggregate increase autophagy degree of enhancement.7)Rat cardiomyocyte autophagy factor related gene expression results: 8 weeks M group Beclin1 was higher than C group(p<0.05),H group and C group compared to the rising more significantly(p<0.01);LC3 of H group was significantly higher than that of C group(p<0.01)and M group(p<0.05);p62 decreased slightly with the increase of intensity.16 weeks group Beclin1 increased with the increase of intensity.H group LC3 was significantly higher than C group(p<0.01)and M group(p<0.01);M and H group p62 was lower than C group(p<0.05).8)Rat cardiomyocyte autophagy factor related protein expression results: 8 weeks H group Beclin1 was higher than C group(p<0.01);With training intensity increased,LC3 II /LC3 I ratio increases and p62 reduces.16 weeks M group Beclin1,LC3? / LC3?ratio was significantly higher(p<0.05),between H group and C group,the difference was more significant(p<0.01)and was higher than M group(p<0.01);p62 of H group was lower than the control group(p<0.05).Conclusion:1)Moderate intensity endurance training can significantly improve the antioxidant capacity of the body,caused by myocardial tissue cells in good adaptive remodeling,promote myocardial cell appropriate levels of autophagy and activity,enhance myocardial cell metabolism.2)Long term high intensity endurance training destroyed the balance of free radicals,which caused oxidative stress damage.Can also lead to myocardial damage,increased autophagy,constitute the pathological basis of the occurrence of myocardial injury.At the same time,excessive oxidative stress can lead to autophagy excessivily of cardiac muscle cells,which constitutes the structure and molecular pathological basis of myocardial cell damage.