Swimming training improves glutathione antioxidant system and oxidative stress biomarker, in a rheumatoid arthritis rat model

Elevated free radical generation in inflamed joints and impaired antioxidant system has been implicated in rheumatoid arthritis (RA). Evidence suggests that exercise improves the symptoms of rheumatoid arthritis, although the mechanism is not well understood. The aim of this study was to investigate the effect of swimming training on the glutathione antioxidant system and oxidative changes induced by rheumatoid arthritis in rats.

8-week-old female Wistar rats were distributed within three groups (n=10 in each): a normal control group (C), a rheumatoid arthritis control group (RA+C), and a rheumatoid arthritis swimming training group (RA+EX). At nine weeks-of-age, rheumatoid arthritis was induced by injection of complete Freundchr('39')s adjuvant (20mg/kg) into the tail of Wistar rats. The degree of arthritis was assessed by macroscopic assessments such as walking ability, skin redness, and swelling in the joints. The RA+EX rats were conditioned to swim for the 4-week period (~20-60 min/day), whereas the C and RA+C remained sedentary in their cages. 48 hours after the last training session, a venous sample was collected to determine metabolic parameters, including glutathione peroxidase, glutathione reductase and lipid peroxidation products (malondialdehyde).The variance analysis test and the Tukey post-hoc test were applied to analyze the data (p < 0.05).

As predicted, rheumatoid arthritis significantly increased levels of malondialdehyde, and swimming training prevented this response (p < 0.05). Interestingly, glutathione peroxidase was significantly decreased in the RA+C group compared to the RA+EX and C groups (p < 0.05). In addition, the severity of rheumatoid arthritis clinical signs in RA+EX group was significantly lower than RA+C group. (p < 0.05).

Our findings suggest that swimming training may be useful in preventing the negative changes in glutathione antioxidant system and oxidative stress parameters related to rheumatoid arthritis.