Exercise preconditioning is special precondition that completes ischemic preconditioning in favor of further advance, and it accelerates endogenouse protective mechanism of apoptosis by exercise stimulation so that it is expected to be one type of physiological cardiac muscle protect that has no potential danger of ischemic stimulation and no limitation in clinical application.
High-intensity exercise stimulation increases the oxygen consumption and causes the ischemia and oxygen deficit in cardiac muscle and repeated exercise preconditioning compose repeated ischemia of cardiac muscle.
Exercise preconditioning means that relative ischemic of cardiac muscle makes protected effects of preconditioning through this exercise stimulation.
Exercise preconditioning is known as one type of ideal physiological cardiac muscle protect in the stage of developmental completion in the way of preconditioning.
Exercise preconditioning that has been known until now is researched from the model of cardiac muscle of ischemia reperfusion that needs complex heart operation and it is not researched about effects of cardiac muscle protect during the exercise preconditioning in the animal model of acute myocardial ischemic injury and the animal model of excessive exercise by β-adrenergic receptor activation.
In biochemistry department, basic medicine faculty of Pyongyang medical college of
The model of acute myocardial ischemic injury was made by injecting isoproterenol in the abdominal cavity of rat and the model of exercise preconditioning and excessive exercise by using small animal treadmill.
The model of exercise preconditioning was imposed the burden with exercise intensity of low-intensity exercise (15m in a minute) and middle-intensity exercise (25 to 30m in a minute) and impose exhaustion in treadmill (a gradient 2), and the model of excessive exercise with high-intensity exercise exhaustion (10 to 25m in a minute) in treadmill (a gradient 10), and sample was gathered.
We observed the with the naked eye hearts to check, made sample of its tissue and had a pathologic histological check.
We measured mitochondria cytochrome c content in cardiac muscle cellular liquid as an index to find a function of intercellular apoptosis and cardiac muscle MDA, GSH content and OX-LDL content in the serum as an index of oxidative stress and CK, LDH, NAG, GOT, GPT activity in the serum as index of cell membrane damage.
Mitochondrial cytochrome c(Cyt c) was extracted by separating mitochondria and cellular liquid layer from hearts of rat and by dialysis-tube electro-elution in vertical polyacrylamide gel electrophoresis(PAGE) device, and measured compared with standard Cyt c.
We also measured MDA and GSH contents in cardiac muscle and measured OX-LDL content and activity of NAG in serum. CK, LDH, GOT and GPT activity in serum was measured by using blood automatic analyzing device. (Hitachi 704-0018)
Myocardial injury indexes and myocardial cell death inhibited when exercise preconditioning for two days while imposing exhaustion as 10-minute exercise at a rate of 25m/min, 5-minute recess, repeated exhaustion of 3 times in a day in treadmill (a gradient 2) the model rat of acute myocardial ischemic injury by isoproterenol.
Exercise preconditioning has a myocardial protective effect on acute myocardial ischemic injury by isoproterenol.
Exercise preconditioning inhibits cardiac muscle necrosis by isoproterenol and decreases cardiac muscle mitochondrial cytochrome c , cardiac muscle MDA and serum OX-LDL significantly(p<0.05) and increases level of cardiac muscle GSH significantly. (p>0.05)
It also decreases activity of serum CK, LDH, NAG, GOT and GPT significantly. (p<0.01)
Exercise preconditioning has a myocardial protective effect on myocardial injury by excessive exercise.
Exercise preconditioning prolongs running time of excessive exercise from 63.5±10.2 minutes to 114.2±21.8 minutes and increases level of cellular liquid cytochrome c, MDA and GSH significantly(0<0.01) and decreases level of serum OX-LDL, and activity of CK, LDH, NAG, GOT and GPT significantly.
Exercise preconditioning is endogenouse protective mechanism in which the efficacy of ischemic preconditioning and the protective mechanism of exercise preconditioning affect simultaneously, so the research should be developed further.
