Omega-3 rich <i>Rastrelliger kanagurta</i> fish oil attenuates IL-6 and MMP-9 expression and preserves joint integrity in rheumatoid arthritis-induced rats

Abstract Objectives Omega-3 polyunsaturated fatty acids are known for their anti-inflammatory potential in autoimmune disorders. This study aimed to investigate the effects of Rastrelliger kanagurta fish oil on pro-inflammatory cytokine IL-6, matrix metalloproteinase-9 (MMP-9), and joint structural preservation in a collagen-induced arthritis rat model. Methods Female Wistar rats with induced arthritis were orally treated with R. kanagurta fish oil (1,000 microliters per day) for 21 days. Clinical assessments included arthritis scoring, paw thickness, and body weight measurements. Serum levels of interleukin-6 and matrix metalloproteinase-9 were determined, and histopathological evaluation of joint tissues was conducted to assess synovial inflammation and cartilage integrity. Results Fish oil treatment significantly reduced arthritis scores, decreased paw thickness, and restored body weight compared with untreated arthritic controls. Serum concentrations of interleukin-6 and matrix metalloproteinase-9 were markedly lowered, approaching values observed in the indomethacin-treated group. Histopathological analysis demonstrated reduced synovial inflammation and preservation of cartilage structure with minimal erosion. Conclusions Rastrelliger kanagurta fish oil demonstrated strong anti-inflammatory and cartilage-protective properties by downregulating interleukin-6 and matrix metalloproteinase-9 pathways. These findings indicate its potential as an affordable and safe adjunctive therapy for rheumatoid arthritis, meriting further investigation through purification, dose optimization, and clinical trials.