Carbonyl Stress In Physical Activity Process

With the intensity increase among teams and athletics in high level sport competitions, to avoid fatigue and injury become more and more important for achieving victories. The accumulative exercise fatigue is one of the main causes of athletics' injury. To understand and clarify the mechanism of development of fatigue may help effectively eliminating different exercise-induced fatigue and thus have great importance in the field.MDA is an intermediate produced during the process of physical activities due to oxidative stress and lipid peroxidation. It is an important index of exercise and stresses, or the so called "exercise stress factors" (ESFs). MDA-related toxic carbonyls can inevitablely formed from the side-reactions of the free radical oxidation and non-enzymatic glycosylation of energy metabolism. MDA, as a representative product containing two carbonyl groups, is detected consistently with oxidative stress and glycation stress during energy metabolism. It's reaction covalently with the amino group (more actively with thiol) to cause cross-linking of different biomolecules, is known as the'carbonyl-amino reaction'. Such reaction with proteins, nucleic acids and further cross-linking with other biological macromolecules have been found to induce extensive and irreparable injury. Such carbonyl poisoning injuries may present everywhere and everyday in human body.Human body prevents oxidative stress with mainly three defense systems, namely anti-oxidative stress, anti-carbonyl stress and repairing systems. The anti-carbonyl stress system is the central defense system. With assistance of glutathione, carbonyl compounds can be cleared and degraded thus to prevent oxidative stress injury. Therefore, based on the mechanism studies of exercise-induced fatigue, and carbonyl stress theory, we propose that the "carbonyl stress may be an important key to understand the exercise-induced fatigue ". This study is aiming to applying carbonyl stress theory of aging as the theoretical basis to investigate the toxicity of the carbonyl substances, such as MDA, in animal exercise-induced fatigue models. Red blood cells model has also been applied to study carbonyl stress. Through measurement of carbonyl stress, various anti-fatigue chemicals were also used in a series of experiments to explore the possible mechanism of exercise-induced fatigue.A significant increase of MDA-related toxicity may increase during exercise and blood storage. A simple experimental model of erythrocytes' carbonyl stress was established. From viscosity and morphology of red blood cells, the protein carbonyl content and fluidity of membrane lipid and many other aspects were investigated. The MDA induced carbonyl stress was assayed by studying the blood viscosity, the electromicroscopic morphology of erythrocytes, protein carbonyl content and fluorescence polarization of membrane of erythrocytes, analysis of productions by LC/MS-ESI. The relation of carbonyl stress and blood viscosity changes has also been studied. Different amino and mercapto containing small molecules have been applied for anti-carbonylation in the defense system. The rat exhaustive exercise treadmill fatigue model was established, and glutathione, taurine, lysine and melatonin were taking into account in the exercise-induced fatigue in amino acid metabolism. Different concentrations of lysine at different pH under different conditions of MDA were also investigated in the sport-related fatigue situation.The results showed that:1. MDA treated red blood cell suspension significantly increased blood viscosity; GSH decreased apparently the viscosity of red blood cells; lOmmol/L MDA caused red blood cells aggregation morphogenesis after treatment; GSH can reverse scattered red blood cells; GSH can significantly lower erythrocyte membrane protein carbonyl content (P＜0.01); 50 mmol/L MDA caused the fluorescence polarization of erythrocyte membrane and increased micro-viscosity; 20,50,100 mmol/L of GSH reduced the red cell membrane fluorescence polarization and microviscosity. In addition, 20mmol/L of GSH treatment did not reach significant level (P>0.05) compared with the control, the rest of the treatment compared with the control reached the significant level (P＜0.01). MT reacted with MDA produce a new product (the maximum absorption peak at 345.Onm); MT also inhibited MDA caused increase of blood viscosity.2. Supplementation of taurine prolonged the running-time in exhaustive exercise of rats, but the control group and treatment group were no significant differences (p＞0.05). After exhaustive exercise significant increase were observed with MDA levels (p＜0.01) and SOD activity. However GSH content and total Ca2+ concentrations were significantly reduced (p＜0.01). Supplementation of taurine reduced the magnitude of this change significantly (p＜0.01), suggesting that taurine can reduce carbonyl toxicity and protect the mitochondrial function.3. In the lysine-related model system, the reaction products of lysine with MDA showed a new 400nm UV absorption peak. The UV absorption peak was positively correlated with MDA concentration and reaction time. The fastest increase of UV absorption peak were in the pH7.4 condition. Exercise can increase the amino acid metabolism in rats, and to increase the concentration of free lysine and MDA, addition of lysine significantly reduced MDA level in rats after acute exhaustive exercise.In summary, through the carbonyl toxicity and related studies, we found that MDA is an useful "exercise stress factors". The carbonyl-amino reaction appeared to be one of the important reasons in the development of exercise-induced fatigue.