大强度运动对心肌肌钙蛋白I及其降解酶μCalpain的影响

目的:观察急性、慢性大强度运动对血清心肌肌钙蛋白I及其降解酶μCalpain的影响。方法:慢性运动组大鼠每天进行120m in负重8%的游泳训练,每周6d共6周,第6周末进行一次性负重8%的力竭运动,急性运动组饲养到第6周末进行一次性负重8%的力竭运动,安静组常规饲养。各组均24h后取材,检测血清cTnI和心肌组织SOD、CAT活性、MDA含量和μCalpain mRNA表达。结果:急、慢性大强度运动后血清cTnI浓度显著上升,伴随μCalpain mRNA表达增加(P<0.001),血清cTnI与μCalpain存在显著相关性(P<0.001),但两个运动组之间血清cTnI水平、μCalpain mRNA表达没有显著差异,血清cTnI与抗氧化酶SOD活性呈显著负相关性。血清cTnI与MDA含量呈正相关,存在显著相关性(P<0.05)。结论:大强度运动可以导致cTnI降解、抗氧化酶活性下降和过氧化物堆积。大强度运动引起氧化应激反应和μCalpain mRNA表达增加,可能是激活μCalpain引起cTnI降解的原因。

The Effect of Intense Exercise Training On cTnI and μ-Calpain-Mediated Proteolysis

Purpose: The goal of this study was to determine the effect of intense exercise training on the serum cTnI and μ-Calpain.Methods: Male rats of the chronic group were forced to swim 120 minutes,with 8% of body weight attached to the tail,6 days per week for 6 weeks.Acute group was forced to swim 120 minutes,with 8% of body weight attached to the tail.Sedentary controls received rat chow and water ad libitum.All the groups were killed 24 h later.Serum cTnI and SOD,CAT,MDA,μ Calpain mRNA of the ventricle tissue were analyzed.Results: The serum cTnI of the acute and chronic group exceed the critical point and increased significantly,with the over express of μ Calpain mRNA(P<0.001).There is significant relationship between serum cTnI and μ Calpain(P<0.001),but there isn`t difference between the two training groups.Serum cTnI has negative relationship with SOD,but positive with MDA significantly(P<0.05).Conclusions: Intense exercise training can induce the degradation of cTnI,the activation of antioxidants and the accumulation of peroxidase.The intense exercise training can induce oxidate stress and upregulation ofμ Calpain mRNA,which can degrade cTnI by the way of upregulating the activion of μ Calpain.