Probable oxidant stress sources which cause exercise-induced proteinuria

ABSTRACTThe increase in oxygen consumption during exercise training leads to anelevation in free oxygen radicals and thus may cause some undesirableconsequences. A previous study in our department showed that postexerciseproteinuria is interrelated with the exercise induced oxidative stres in rats.This project was planned to reveal the probable sources leading toexercise proteinuria. This investigation will be focused on effects of NADPHoxidase and xanthine oxidase inhibitors on exercise proteinuria. Our projectis assembled as an investigation of two different studies. Two separate groupwas exposed to exhaustive treadmill exercise after administration of NADPHoxidase and xanthine oxidase inhibitors as diphenyleneiodonium chloride(1.6mg/kg/day) and oxypurinol (40mg/kg/day) respectively. All rats werehaused individually in metabolic cages for the next 24 hours after exercise tocollect urine samples. Blood withdraval and kidney tissue isolation were alsoperformed beside urine samples. NADPH oxidase activity and leukocyteactivation were determined in first study?s groups while xanthine oxidaseactivity was evaluated in oxypurinol treated group. Blood and kidneythiobarbituric acid reactive substances (TBARS), and protein carboyl contentwere measured in approach to evaluate the oxidant status in both studies.Proteinuria was asessed by detecting total urine protein, β2-microglobulinand albumin leves in urine samples.In NADPH oxidase study total protein excreation and albumin levels inExercise group significantly increased in comparison with Control whileinhibitor treatment prevented this increase in Exercise-Inhibitor group. Excepterythrocyte TBARS the other oxiadant stress parameters ,kidney TBARS andkidney protein carbonylation apperantly increase in Exercise group and thisincrease was also prevented in inhibitor receivig Exercise-Inhibitor group.Leukocyte and kidney NADPH oxidase activities and leukocyte activity inExercise group significantly increased. In accordance with urinary andoxidant stress parameters, this increase was smilarly prevented by inhibitoradministration.Urinary total protein and albumin excreation was found to be increasedin xanthine oxidase study, but this effect was not altered by inhibitoradministration. However oxidant stress parameters except erythrocyteTBARS, the kidney TBARS and protein carbonylation exhibited significantlyincrease and this elevation was prevented by inhibitor administration.Exercise did not induce an increase in plasma and kidney xanthine oxidaseactivity but inhibitor treatment reduced the enzyme activity in both Inhibitorand Exercise Inhibitor groups.Our findings indicates that NADPH oxidase enzyme, rather than xanthineoxidase, plays a role as a source of oxidant stress in accurance ofpostexercise proteinuria.Key words: Exercise, proteinuria, NADPH oxidase, xanthine oxidasev