Curcumin improves myocardial redox status in an experimental model of rheumatoid arthritis

Curcumin, a natural polyphenol derived from turmeric, possesses potent antioxidant properties and represents a potential cardioprotective agent capable of mitigating myocardial oxidative stress associated with rheumatoid arthritis (RA). The aim of the study was to examine the cardioprotective effect of curcumin in an experimental model of rheumatoid arthritis. The study included 104 female Wistar albino rats, divided into 8 groups (n = 13 in each group): (1) CTRL (negative control, healthy rats without treatment), (2) CUR (positive control 1, curcumin 200 mg/kg three times a week for 4 weeks orally), (3) MTX (positive control 2, methotrexate 0.75 mg/kg twice a week for 4 weeks intraperitoneally), (4) RA (positive control 3, rats with Complete Freund's adjuvant (CFA)-induced RA), (5) RA+pCUR (rats with preventive administration of curcumin + CFA-induced RA), (6) RA+tCUR (rats with CFA-induced RA + therapeutic administration of curcumin), (7) RA + MTX+pCUR (rats with preventive administration of curcumin + CFA-induced RA + methotrexate), (8) RA + MTX+tCUR (rats with CFA-induced RA + therapeutic administration of curcumin + methotrexate). Pro-oxidant levels were determined in coronary venous effluent, antioxidant enzyme activities were assessed in heart tissue homogenates, and histopathological analyses of the synovium and myocardium were performed. Curcumin, particularly in the therapeutic regimen and in combination with methotrexate, significantly reduced pro-oxidant levels and lipid peroxidation. Curcumin also increased superoxide dismutase activity and restored reduced glutathione levels, whereas improvement in catalase activity was observed predominantly in the therapeutic regimens. Histopathological analyses demonstrated that curcumin exerted a protective effect on both synovial and myocardial tissues, attenuating RA-induced structural damage, reducing edema, and preserving myocardial architecture. These findings suggest that curcumin improves myocardial redox homeostasis and may contribute to cardioprotection in experimental RA.