Mechanism of Gardeniae Fructus in ameliorating rheumatoid arthritis based on metabolomics and intestinal microbiota

Abstract

Rheumatoid arthritis(RA), a chronic autoimmune disease, is featured by persistent joint inflammation. The development of RA is associated with the disturbance of endogenous metabolites and intestinal microbiota. Gardeniae Fructus(GF), one of the commonly used medicinal food in China, is usually prescribed for the prevention and treatment of jaundice, inflammation, ache, fever, and skin ulcers. GF exerts an effect on ameliorating RA, the mechanism of which remains to be studied. In this study, ultra-perfor-mance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)-based serum non-target metabolomics and 16S rDNA high-throughput sequencing were employed to elucidate the mechanism of GF in ameliorating RA induced by complete Freund's adjuvant in rats. The results showed that GF alleviated the pathological conditions in adjuvant arthritis(AA) rats. The low-and high-dose GF lo-wered the serum levels of interleukin(IL)-6, tumor necrosis factor-α(TNF-α), IL-1β, and prostaglandin E2 in the rats(P<0.05, P<0.01). Pathways involved in metabolomics were mainly α-linolenic acid metabolism and glycerophospholipid metabolism. The results of 16S rDNA sequencing showed that the Streptococcus, Facklamia, Klebsiella, Enterococcus, and Kosakonia were the critical gut microorganisms for GF to treat AA in rats. Spearman correlation analysis showed that the three differential metabolites PE-NMe[18:1(9Z)/20:0], PC[20:1(11Z)/18:3(6Z,9Z,12Z)], and PC[20:0/18:4(6Z,9Z,12Z,15Z)] were correlated with the differential bacteria. In conclusion, GF may ameliorate RA by regulating the composition of intestinal microbiota, α-linolenic acid metabolism, and glycerophospholipid metabolism. The findings provide new ideas and data for elucidating the mechanism of GF in relieving RA.