Hemp seed oil ameliorates CFA-induced rheumatoid arthritis in rats by improving metabolic abnormalities and gut microflora

Hemp seed oil (HSO) acquired from hemp seeds (Cannabis sativa L.) is rich in polyunsaturated fatty acids and has been claimed for centuries to be beneficial for atopic dermatitis and inflammation. In this study, we investigated the beneficial effects of HSO against complete Freund's adjuvant (CFA)-induced RA using 16S rRNA amplicon sequencing technology and metabolomics. Our findings demonstrated that HSO effectively alleviated rheumatoid arthritis symptoms such as paw swelling, synovial hyperplasia, joint inflammation, and bone destruction. Moreover, nuclear magnetic resonance (NMR)-based metabolomics revealed that fifteen potential biomarkers associated with RA in both serum and urine were restored to near normal levels by the administration of HSO. The 16S rRNA gene sequencing analysis revealed that the composition and number of the intestinal flora were restored to healthy levels in RA rats treated with HSO. These results suggested that HSO may attenuate RA by modulating gut microbiota composition and regulating metabolic abnormalities.