Docosahexaenoic acid algal oil reduces arthritis severity more effectively than fish oil in a mouse model of collagen‐induced arthritis

Omega‐3 fatty acids (n‐3), such as EPA and DHA, have been associated with the amelioration of chronic and acute inflammation. Although the efficacy of fish oil has been the subject of research in arthritis, the anti‐arthritic effect of DHA has yet to be investigated. The objective of this study was to compare the anti‐arthritic activity of DHASCO TM oil, a DHA‐rich algal oil that contains no EPA, to fish oil containing both DHA and EPA, in an arthritis model. Mice were provided ad libitum access to diets supplemented with 2500 mg/kg polyunsaturated fatty acids for 4 weeks prior to disease induction and throughout the course of the study. Treatment with DHASCO oil and not fish oil significantly reduced arthritis severity, delayed disease onset and decreased arthritis incidence. Consistent with this, DHASCO oil treatment decreased anti‐collagen antibody production, whereas fish oil had no effect. Histopathologic analysis of the joints showed an overall reduction in inflammation, bone and cartilage damage in animals treated with DHASCO oil. These results demonstrate that DHASCO oil is more potent than fish oil in reducing arthritis and suggests that DHA may be a useful intervention strategy against signs of inflammatory arthritis. Moreover, since the treatments were matched for n‐3 content, these results demonstrate a higher efficacy of DHA over EPA for prevention of collagen‐induced arthritis.