TY - JOUR

T1 - Xanthine oxidase in human skeletal muscle following eccentric exercise

T2 -  a role in inflammation

AU - Hellsten, Ylva

AU - Frandsen, Ulrik

AU - Orthenblad, N.

AU - Sjødin, B.

AU - Richter, Erik A.

N1 - Keywords: Adult; Exercise; Humans; Immunohistochemistry; Inflammation; Male; Muscle, Skeletal; Muscular Diseases; Xanthine Oxidase

PY - 1997

Y1 - 1997

N2 - 1. The present study tested the hypothesis that the level of xanthine oxidase is elevated in injured human skeletal muscle in association with inflammatory events. Seven male subjects performed five bouts of strenuous one-legged eccentric exercise. Muscle biopsies from both the exercised and the control leg, together with venous blood samples, were obtained prior to exercise and at 45 min, 24, 48 and 96 h after exercise. The time courses of xanthine oxidase immunoreactivity and indicators of muscle damage and inflammation were examined. 2. The number of xanthine oxidase structures observed by immunohistological methods in the exercised muscle was up to eightfold higher than control from day 1 to day 4 after exercise (P < 0.05). The increase was attributed to an enhanced expression of xanthine oxidase in microvascular endothelial cells and an invasion of leucocytes containing xanthine oxidase. 3. The concentration of plasma interleukin-6 was significantly higher 90 min after exercise than before exercise (P < 0.05) and remained higher than pre-exercise levels throughout the 4 days. On day 4 the plasma creatine kinase activity was approximately 150-fold higher (P < 0.05) than resting levels. 4. Despite the increase in xanthine oxidase in the muscle there were no detectable changes in the levels of muscle malondialdehyde or in plasma antioxidant capacity up to 4 days post-exercise. 5. It is concluded that eccentric exercise leads to an increased level of xanthine oxidase in human muscle and that the increase is associated with secondary inflammatory processes. The increase in xanthine oxidase in the muscle occurs mainly in microvascular endothelial cells, but occurs also via infiltrating leucocytes containing xanthine oxidase. A role for leucocytes in xanthine oxidase induction in endothelium is proposed.

AB - 1. The present study tested the hypothesis that the level of xanthine oxidase is elevated in injured human skeletal muscle in association with inflammatory events. Seven male subjects performed five bouts of strenuous one-legged eccentric exercise. Muscle biopsies from both the exercised and the control leg, together with venous blood samples, were obtained prior to exercise and at 45 min, 24, 48 and 96 h after exercise. The time courses of xanthine oxidase immunoreactivity and indicators of muscle damage and inflammation were examined. 2. The number of xanthine oxidase structures observed by immunohistological methods in the exercised muscle was up to eightfold higher than control from day 1 to day 4 after exercise (P < 0.05). The increase was attributed to an enhanced expression of xanthine oxidase in microvascular endothelial cells and an invasion of leucocytes containing xanthine oxidase. 3. The concentration of plasma interleukin-6 was significantly higher 90 min after exercise than before exercise (P < 0.05) and remained higher than pre-exercise levels throughout the 4 days. On day 4 the plasma creatine kinase activity was approximately 150-fold higher (P < 0.05) than resting levels. 4. Despite the increase in xanthine oxidase in the muscle there were no detectable changes in the levels of muscle malondialdehyde or in plasma antioxidant capacity up to 4 days post-exercise. 5. It is concluded that eccentric exercise leads to an increased level of xanthine oxidase in human muscle and that the increase is associated with secondary inflammatory processes. The increase in xanthine oxidase in the muscle occurs mainly in microvascular endothelial cells, but occurs also via infiltrating leucocytes containing xanthine oxidase. A role for leucocytes in xanthine oxidase induction in endothelium is proposed.

M3 - Journal article

C2 - 9023782

VL - 498

SP - 239

EP - 248

JO - The Journal of Physiology

JF - The Journal of Physiology

SN - 0022-3751

IS - 1

ER -