THE ROLE OF XANTHINE OXIDASE ON FREE RADICAL FORMATION IN MUSCLE FOLLOWING EXERCISE

Abstract

1375 The objective of this study was to examine the role of xanthine oxidase on free radical formation during exercise. Allopurinal were used to inhibit the activity of xanthine oxidase. The membrane fluidity of mitochondria and the milondialdehyde (MDA) content were used to indicate the oxidative stress. 100 rats were divided into exercise control and drug groups. The rats in drug group were administrated with allopurinal 50mg/kg/day, twice a day by intragastric gavage for four days before exercise. The rats in exercise control group were treated with water as same volume and time as allopurinal. Every ten rats in both groups were sacrificed at designed time points, pre-exercise, and immediately, 24h, 48h, 72h and 96h post exercise. The rats ran to exhaustion on the treadmill with incremental exercise intensity. The membrane fluidity of intact mitochondria from gastrocnemius were detect by fluorescence polarization method with lipid probe 1,6-diphenyl-1,3,5-hexatriene. MDA in muscle homogenate were assayed by thiobarbitoric acid reaction. The results showed that the membrane fluidity significantly reduced after exercise and did not recover until 96 h post running; MDA contents significantly elevated immediately post running and down to the control level 24 h after exercise. No significant differences in membrane fluidity of mitochondria and MDA contents were found between the both groups, suggesting that xanthine oxidase might not be a major source of free radical formation in the model used in this study.