Attenuation of collagen induced arthritis by Centella asiatica methanol fraction via modulation of cytokines and oxidative stress.

OBJECTIVE To investigate the anti-inflammatory, antioxidant and anti-arthritic effects of Centella asiatica methanolfraction (CaME) on collagen-induced arthritis (CIA), an animal model of rheumatoid arthritis. METHODS Arthritis was induced in female wistar rats by immunization with porcine type II collagen. The CIA rats were treated orally with CaME (50, 150, and 250 mg/kg/day) for 15 d (beginning on day 21 of the experimental period). The clinical, histological, biochemical, and immunological parameters were assessed. RESULTS CaME treatment (150 and 250 mg/kg) significantly attenuated the severity of CIA and reduced the synovial inflammation, cartilage erosion, and bone erosion as evident from both histological and radiographic data. The escalated plasma levels of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and IL-12 alongwith nitric oxide in CIA rats decreased significantly on CaME treatment. The serum levels of type-II collagen antibody were significantly lower in rats of CaME (150 and 250 mg/kg) treated group than those in the arthritic group. Furthermore, by inhibiting the above mediators, CaME also contributed towards the reversal of the disturbed antioxidant levels and peroxidative damage. CONCLUSION Our results clearly indicate that oral administration of CaME suppresses joint inflammation, cytokine expression as well as antioxidant imbalance, thereby contributing to an amelioration of arthritis severity in CIA rats.