Assessment of total peroxidase activity and its relationship with vitamin D in Iraqi rheumatoid arthritis patients

Abstract

Objective: In a previous work carried on in our laboratory, a positive correlation were recorded between different levels of vitamin D and the antioxidant status in Iraqi patients with rheumatoid arthritis, meanwhile some of peroxidases family have been known to act as antioxidant. Therefore in order to look for the molecular level of this action of vitamin D, the impact of different vitamin D levels on peroxidases activity in Iraqi rheumatoid arthritis patients was investigated. Method: The study included 119 patients with rheumatoid arthritis (who were matched in age range and body mass index range). Vitamin D was measured by Roche Elecsys vitamin D total II assay, total peroxidase activity was measured by Song's method and total protein was determined by biuret method. Results: The studied participants in this study were divided into four groups according to their vitamin D levels into: G1 (n=31), G2 (n=30), G3 (n=30) and G4 (n=28), through -out the present study group G4 was used as a control for the comparison purpose. The results indicated that total peroxidase activity and specific activity were highly significantly increased (p<0.001) in patients with severe deficient vitamin D level (G1), and were significantly increased (p<0.05) and highly significantly increased (p<0.001) respectively in patients with deficient vitamin D level (G2). While peroxidase activity and specific activity did not show a significant increase (P>0.05) in patients with insufficient vitamin D level (G3). Conclusion: In rheumatoid arthritis patients, vitamin D level affects peroxidases activity, as concluded from the negative counterbalance relationship that was found between the level of vitamin D and peroxidases activity.