This study investigated the effects of chronic muscle
inflammation on indices of
antioxidant status and muscle injury after eccentric exercise. Eight subjects each performed 70 maximal voluntary eccentric muscle actions on an isokinetic dynamometer, using the knee extensors of a single leg. Venous blood samples were collected into serum and
EDTA tubes 5 and 3 days before exercise, immediately before exercise, and then again on days 3, 4, 5, 6, 7, 10 and 12 after the bout. Needle biopsies were taken from the vastus lateralis of six subjects, a week before exercise (baseline), and again on days 4 and 7 post-exercise. The concentrations of
malondialdehyde in plasma and muscle were used as markers of lipid peroxidation.
Creatine kinase activity,
beta-glucuronidase activity and total
antioxidant capacity were determined in serum. In muscle, aqueous and bound total
antioxidant capacity, the aqueous sulphydryl concentration, and
beta-glucuronidase and
glucose-6-phosphate dehydrogenase activity were determined. No changes were detected in serum total
antioxidant capacity, serum
creatine kinase and
beta-glucuronidase after the baseline biopsy. After exercise serum
creatine kinase and
beta-glucuronidase were elevated although other serum measures were unchanged. In muscle, aqueous and bound total
antioxidant capacity, sulphydryls,
glucose-6-phosphate dehydrogenase and
beta-glucuronidase were all elevated. Despite evidence of
inflammation in this study, muscle
antioxidant status was not compromised, and
malondialdehyde was unaltered in muscle and plasma. Therefore, this study provides no evidence that chronic muscle
inflammation compromises
antioxidant status or increases lipid peroxidation.