The Research Of The Heart Protective Effection Of Exercise Preconditioning That Are Mediated By Calcitonin Gene Related Peptide On Acute Exhaustion Rats

Calcitonin gene related peptide(CGRP)is a strong diastolic vasoactive substance.In the heart,CGRP mainly exists in atrial tissue,ventricular group and coronary artery wall.CGRP has positive inotropic and inotropic effects on myocardium,which can accelerate heart rate,increase myocardial contraction,increase cardiac output,and relax coronary artery and increase myocardial perfusion.CGRP has an important regulatory effect on the protection of heart damage,but its mechanism and influencing factors are still unclear.Acute high intensity exhaustive exercise can produce myocardial injury,and exercise preconditioning on myocardial protective effect of myocardial and release of endogenous protective substances,and CGRP as one of endogenous myocardial protective material,plays a very important role in myocardial protection in the exercise preconditioning.Eighty adult male SD rats of pathogen-free were divided into control group(C),exercise preconditioning group(EP),exercise preconditioning and acute exhaustion exercise group(EP+EE)and acute exhaustion exercise group(EE)randomly,every group had 20 rats.C group don't do any exercise,EE group carried out an acute exhaustive swimming exercise,EP group and EP+EE group swimed 60 minutes every day(swim 15 min,rest 5min,repeat 3 times),trained 3 weeks,EP+EE group carried out a swimming exhaustion the day after the pre-adaptation.The lultrastructure of myocardium was observed by optical microscopy;The lultrastructure of myocardium was observed by optical microscopy;The contents of myocardial malondialdehyde(MDA),superoxide dismutase(SOD)and nitrogen monoxide(NO),and serum creatine kinase isoenzyme(CK-MB)and CGRP were determined by ELISA method;The m RNA expression ofmyocardial CGRP by reverse transcription-polymerase chain reactio(RT-PCR),and the protein expression level of myocardial CGRP was assayed by Westen Blot.The results showed that: EP could improve the loss of myocardial structure in rats.Compared with group C,the levels of serum CK-MB,myocardial MDA and NO in EE group and EP+EE group were significantly increased [CK-MB(U/L): 15.55±0.90,13.11±0.77 vs.7.38±0.41;MDA(?mol/L): 709.08±160.49,389.57±49.60 vs.216.56±19.70;NO(?mol/L): 13.43±0.95,12.20±0.87],serum CGRP content,myocardial SOD activity,and m RNA and protein expression of myocardial CGRP were significantly decreased [CGRP(ng/L): 97.97±9.05,120.41±9.07 vs.193.39±28.05;SOD(?g/L): 6.25±1.25,8.371±0.97 vs.18.04±3.69;CGRP m RNA(2-??CT): 0.14±0.02,0.45±0.09 vs.0.98±0.11;CGRP(gray value): 0.41±0.04,0.78±0.08 vs.1.24±0.15],with statistically significant differences(all P < 0.05).Compared with EE group,the levels of serum CK-MB and myocardial MDA were declined,and the level of serum,m RNA and protein expression of myocardium CGRP were increased in EP+EE group(all P < 0.05).Conclusion: EP has the heart protective effection to the acute exhaustion exercise rats,and the mechanism is closely related to the endogenous protective substance CGRP.