Evaluation of the effect of vitamin C on caspase 9 and oxidative stress in rheumatoid arthritis patients

Rheumatoid arthritis (RA) is a chronic and an autoimmune disease of the joints and is widely distributed worldwide. It is characterized by alterations of the antioxidant defense system and increased free radical formation and pro-inflammatory cytokine. The aim of the present study was to evaluate the effect of vitamin C supplementation on oxidative stress biomarkers and caspase 9 level in rheumatoid arthritis patients. This study included 30 RA patients and 30 healthy subjects. Plasma levels of malondialdehyde (MDA), total antioxidant capacity (TAC), caspase 9 and 8-hydroxy-2′-deoxyguanosine (8 OHdG) were assayed as well as blood vitamin C level. These parameters were re-evaluated in RA patients after vitamin C supplementation for one month. Increased MDA and 8 OHdG levels and reduced TAC, caspase 9 and vitamin C. Levels were demonstrated in RA patients. After vitamin C supplementation, RA patients showed significant increase in TAC and vitamin C level and significant decrease in MDA and 8 OHdG levels, plasma caspase 9 level was not significantly affected after vitamin C supplementation. Increased oxidative stress and decreased apoptosis may have an important role in the pathogenesis of RA. The administration of vitamin C supplementation may help to relieve oxidative stress and enhance the antioxidant defense in these patients.   Key words: Rheumatoid arthritis, oxidative stress, apoptosis, caspase 9, vitamin C.