Gambogic acid suppresses inflammation in rheumatoid arthritis rats via PI3K/Akt/mTOR signaling pathway

Gamboge is the dried resin secreted by the Garcinia maingayi gambogic tree and is a substance that may be used to treat a variety of diseases, exhibits anti-tumor and detoxification effects and prevents bleeding. The primary active constituent is gambogic acid. The present study aimed to investigate the anti-inflammatory effects of gambogic acid in rheumatoid arthritis (RA) rats and to elucidate the mechanisms by which these effects occur. The swelling degree, the clinical arthritic scoring and pain threshold measurements were used to evaluate the effects of gambogic acid on RA. ELISA kits and western blot analysis were used to investigate inflammatory processes and the expression of RA-associated proteins, respectively. The present results demonstrated that gambogic acid significantly inhibited the degree of right foot swelling, increased pain thresholds and reduced clinical arthritic scores of RA rats. Treatment with gambogic acid suppressed the activities of interleukin (IL)-1 beta and IL-6, promoted the protein expression of phosphorylated (p)-Akt serine/threonine kinase (Akt), p-mammalian target protein of rapamycin (mTOR) and inhibited hypoxia-inducible factor-1 alpha and vascular endothelial growth factor expression in RA rats. The results of the present study therefore suggest that the anti-inflammatory effects of gambogic acid in RA rats occur via regulation of the phosphoinositide 3-kinase/Akt/mTOR signaling pathway.