Egzersiz ÃevrimiÃ§i Dergi - SÃ¼leyman Demirel Ãniversitesi

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Methods Plasma methaemoglobin concentrations were analyzed immediately after the blood samples are collected aand its level was measured spectrophotometrically according to Fairbanks and Klee (1987). MDA was estimated according to method of Draper and Hardley (1990) which is based on the coupling MDA with thiobarbituric acid. Plasma antioxidant activity (AOA) was measured according to method of Koracevic et al. (2001). Briefly, a standardised solution of Fe– EDTA complex reacts with hydrogen peroxide by a Fenton-type reaction, leading to the formation of hydroxyl radicals. Nitric oxide metabolites (nitrates+ nitrites, NO×) were assayed in plasma by colorimetric method of Griess (Miranda et al. 2001). Total protein, total cholesterol, glucose and triglycerides levels were measured using the commercially available assay kits (TECO Diagnostics, California, USA). Statistical analyses of data from the experiment were analyzed with SPSS statistical software (SPSS for Windows; Release 10.0.1 Standart Version) using paired t test. Results For all subjects, MDA and glocose concentrations increased after exercise(p
egzersiz 2007 • Sayı 2 • No: 1 22 al. 2000). Also used as an indicator of oxidative stress is total antioxidant capacity. There have been studies for exercices at different types and intensities (Defaux et al. 1997). For acut exercices it has been observed that AOA level does not change; whereas, MDA level increases after physical activity. Similarly, no AOA change (for the sample after competition) is observed at our study (Table 1). It is also possible that the intensity and/or the duration of exercise performed in the present study was not great enough to produce a significant increase in MDA and AOA. The primary function of red blood cells is to maintain aerobic metabolism by transporting oxygen to, and carbon dioxide from, body tissues. The iron atom of the heme molecule must be in the ferrous (+2) oxidation in order for this to occur. Certain chemical processes within the cell oxidize the ferrous iron to the ferric (+3) state. This molecule is known as methemoglobin and is unable to bind oxygen, or carbon dioxide, and is not dissociable. Methemoglobin formation is not only affected by nitrite but also by other factors such as rate of methemoglobin reductase, abnormalities of the hemoglobin itself, or oxidant chemicals. Auto-oxidation of oxyhemoglobin to methemoglobin results in the production of superoxide and the rate of formation of methemoglobin can increase with exercise (Deaton et al. 2003). In the present stduy, the methemoglobin level in the blood of footboller after footboll competition elevated similarly the increases of MDA concentration. This result showed that an enhanced production of free radicals caused the methemoglobin formation in the blood of the footboller. Nitric oxide (NO) released by endothelial cells is an important regulator of vascular function. However, excess NO production may cause damage in cells because of being a free radical with vasodilatory properties of NO (Sainz et al. 2005). After the marathon race, metabolic products of NO in plasma of the marathon racer increased up to 1.6 fold, probably due to increased inducible NO synthase expression and NO synthesis in peripheral leukocytes (Pawloski et al. 2001). In the present study, there have been no significant changes on metabolic products of NO (Tab. 1) most probably due to being lower duration and intensity of football matches than marathon races. Many studies on the effects of physical activity on lipid mobilization are found during the literature investigation. Aguilo et al. (2003) reported that the mobilisation of serum triglyceride observed after exercise is related to the release of free fatty acids from the periphery, mainly due to considerable energy expenditure during the cycling stage. In the present study, it has been observed that intensive exercise does not effect the triglyceride and total cholesterol levels for people performing regular exercise (Tab. 1). An increase in cholesterol levels has been observed after acute exercise, but not after choronic exercise (Aguilo et al. 2003) which agrees with our results, because maximal exercise is acute exercise (Short term and high intensity). Excess physical exercise is one of the main causes of increased free radical production and has an important role in hyperglycemia and enhanced lipid mobilization (Gambelunghe et al. 2001). Catecholamine metabolism, which is also increased by exercise and free faty acid, may also participate in the formation of lipid peroxides (Özbay et al.2001). Another aim of this study was to examine the effects of changes in plasma glucose during football competition. As observed in previous studies, plasma glucose concentrations are increased as a result of physical exercise. In conclusion, our results showed that a high competition sport leads to an increased lipid peroxidation, unchanged antioxidant activity and elevated methemoglobin level for football players. This may indicate that the oxidant-antioxidant balance is changed by intensive exercise even if people make regular physical exercise. We suggest that, consumption of natural antioxidants before intensive exesrcises would have a positive effect on being decreased the harmfull of effects of oxidative stress to the cells.
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Egzersiz ÃevrimiÃ§i Dergi - SÃ¼leyman Demirel Ãniversitesi