The Mechanism About Exercise Preconditioning Protect Myocardial By Means Of Regulate NLRP3 Inflammasome Signal Pathways On Exhaustion Exercise Rats

Ischemic preconditioning(IP) is mean that repeated transience ischemia can make the heart damage in the later period of continuous ischemia time is reduced, and can prolong time of ischemic myocardial cells of lethal damage. There are many ways to cause this preadaptation, exercise rely on the advantages of simple and practicable, is becoming a hot spot of research in the cause of preadaptation which is called exercise preconditioning(EP), Can produce sample of IP protection. According to the exercise cycle, EP can be divided into short-term exercise preadaptation and long-term exercise preadaptation, and different period of exercise at different levels in the protection of the heart, long-term exercise preconditioning compared with short-term preadaptation, the first mentioned of two is more significant in the protection of the heart. At present, about the study of exercise preadaptation have protective effect on heart is less used in exhaustion exercise and more not from the perspective of inflammasome angle to argument, this is subject to our further research.Exhaustion exercise refers to under the condition of body fatigue, make it continue to stay in motion, until completely unable to exercise. Acute exhaustive exercise induced myocardial injury has a lot of proof, but is less discussed from the angle of inflammasome. This experiment by builded exercise preconditioning rats and acute swimming exhaustion exercise model, from the angle of the inflammasome to observe that whether exercise preconditioning can reduce the myocardial injury which is caused by exhaustion exercise.NLRP3 inflammasome is an important component of the innate immune body, it is responsible for the feelings of the body tissue damage, stress, the invading pathogens such as danger signals and make the body produce effective adaptive immune response, to protect the body plays a crucial role. Prior researches were shown that NLRP3 inflammasome exist in myocardial ischemic injury, such as myocardial ischemia reperfusion cabg, heart transplantation, and by activit downstream of inflammatory factors, give priority to IL-1 beta and IL-18, causing inflammation and increase myocardial injury, and it's all part of NLRP3, ASC, Caspase-1 are involved, but at the moment about the research of NLRP3 inflammasome relate with exhaustion exercise induced myocardial injury is insignificant. This study discuss on mechanism about different exercise preconditioning protect myocardial by means of regulate NLRP3 inflammasome signal pathways on exhaustion exercise rats.Sixty Sprague-Dawley(SD) rats were randomly divided into four groups: normal control group(C group), exhausive exercise group(EE group), 3 days exercise preconditioning plus exhausive exercise group(3d EP+EE group), 3 weeks exercise preconditioning plus exhausive exercise group(3w EP+EE group). In normal control group and exhausive exercise group, the rats did nothing exercise, while exhausive exercise group took an exhaustion swimming exercise at the end of 3 weeks; 3d EP+EE group and 3w EP+EE group according to the standard of swam 60 minutes every day(swam 15 minutes, took a rest for 5 minutes, repeated 3 times), 6days in a week, and were trained for 3 days, 3 weeks respectively. A light microscope and electron microscope were used to observe the pathological changes in heart tissues, the levels of Interleukin 1 beta(IL-1?), Interleukin 18(IL-18), Interleukin 6(IL-6), hypersensitive C-reactive protein(hs-CRP), Creatine kinase isoenzyme(CK-MB), Brain natriuretic peptide(BNP) in serum were detected by enzyme linked immunosorbent assay(ELISA).The levels of protein of NLRP3 and Caspase-1 were detected by Western Blot. Using the correlation analysis the relationship aong of serum IL-1 beta, IL-18, IL-6, hs-CRP, BNP, CK-MB and their relation with the NLRP3, Caspase-1 protein expressions. 1. In rats after acute exhaustion exercise, Light microscope showed: C group rats heart tissues were stained even, myocardial fiber morphological structure normal and in order, no stroma edema, myolemma damage and myocardial cell swell; EE group heart tissues were stained obviously uneven, a large number of myocardial fibers were fractured and messed, interstitial fibers were hyperplasiaed and edemaed moderately, much of myocardial cells were edemaed and necrosised; 3d EP+EE group and 3w EP+EE group cardiac muscle were stained slightly even,less of fractured myocardial fibers and swelled necrosis myocardial cells. among the three groups, the best results being in the 3w EP+EE group. 2. In rats after acute exhaustion exercise, Electron microscopy showed that: In C group, the number and shape of mitochondria was normal, no edema in muscle fiber, sarcomere was clear and regulate, rich and intact mitochondria were distributed between myofibril, no swell, deformation, and so on. Pathological changes of myocardial ischemia and hypoxia in EE group: mitochondrial matrix electron density increased, severe edema of the partial mitochondrial, nuclear matrix end in mitochondrial cristae and a small part of the film fusion, vague and crest fracture, myocardial irregularly, muscle fibers became thicker and sarcomere was incomplete and disorder. Although there were some changes in 3d EP+EE group and 3w EP+EE group, part of the mitochondrial membrane and the membrane mixed still, unclearly, but the degree is lighter than EE group, the mitochondria edema and sarcomere disorder reduced significantly, among the three groups, the best results being in the 3w EP+EE group, no mitochondria edema and sarcomere disorder. 3. Exercise preconditioning on exhaustion exercise rats by the change of serum of CK-MB: Compared with the C group, the CK-MB levels was increased significantly in EE group, 3d EP+EE group and 3w EP+EE group(P<0.01). There were remarkable statistical significance when EE group compared with the 3d EP+EE group and 3w EP+EE groups(P<0.01).There was a remarkable statistical significance between the 3d EP+EE group and 3w EP+EE group(P<0.01). 4. Exercise preconditioning on exhaustion exercise rats by the change of serum of BNP: Compared with the C group, the BNP levels was increased significantly in EE group, 3d EP+EE group(P<0.01).There were remarkable statistical significance when EE group compared with the 3d EP+EE group and 3w EP+EE group(P<0.01). 5. Exercise preconditioning on exhaustion exercise rats by the change of serum of IL-1??IL-18?IL-6?hs-CRP: Compared with the C group, serum IL-1 beta?IL–18?hs-CRP levels were significantly elevated in EE group?3d EP+EE group and 3w EP+EE group, there was a significant difference(P<0.01). There were significant statistical significance when EE group compared with the 3d EP+EE group and 3w EP+EE group(P<0.01). There was a remarkable statistical significance between the 3d EP+EE group and 3w EP+EE group(P<0.01). Compared with the C group, serum of IL- 6 level was increased significantly in EE group and 3d EP+EE group, there was a remarkable statistical significance(P<0.01). EE group compared with 3d EP+EE group and 3w EP+EE group, there were remarkable statistical significance(P<0.01). There was a remarkable statistical significance when 3d EP+EE group compared with 3w EP+EE group(P<0.01). 6. The influence of exercise preconditioning to exhaustion exercise in rats in myocardial NLRP3?Caspase-1 protein expression: Compared with C group, NLRP3, Caspase-1 protein expression significantly increased in EE group, 3d EP+EE group and 3w EP+EE group(P<0.01); Compared with EE group, NLRP3, Caspase-1 protein expression significantly reduced in 3d EP+EE group and 3w EP+EE group(P<0.01). NLRP3, Caspase-1 protein expression in 3w EP+EE group were most obviously reduced(P<0.01). 7. The correlation of serum of IL-1??IL-18?IL-6?hs-CRP?BNP?CK-MB and myocardial NLRP3?Caspase-1 protein expression: There were positive correlation among IL-1??IL-18?IL-6?hs-CRP?BNP?CK-MB and NLRP3?Caspase-1 protein expression(P<0.01), At the same time, there was a highly positive correlation between NLRP3?Caspase-1 protein expression. Between serum of IL-1 beta?IL-18?IL-6?hs-CRP?BNP?CK- MB also existed a positive correlation.To summary, exercise preconditioning can reduce myocardial injury caused by exhaustion exercise,long-term exercise preconditioning in the protection of the heart is more obvious;inflammatory factors involved in the myocardial injury after exhaustion exercise, NLRP3 inflammatsome has close relations with myocardial injury; the mechanism about exercise preconditioning reduce myocardial injury may be relate to exercise preconditioning regulate the NLRP3 inflammatsome signal pathways, reduce the inflammatory reaction.