Therapeutic effect of Yunnan Baiyao on rheumatoid arthritis was partially due to regulating arachidonic acid metabolism in osteoblasts.

In order to explore the potential therapeutic effect of Yunnan Baiyao (YNB) on rheumatoid arthritis (RA), rat models were constructed and orally administrated with YNB or methotrexate (MTX) in parallel. Clinical physical, histological and biochemical parameters showed trivial therapeutic difference between YNB and MTX applications. Urine and serum metabonomics results indicated that many endogenous metabolites differentially changed among the rats receiving diverse therapeutic interventions. Among them, the fluctuation of arachidonic acid (AA) was thought to make sense. Thus, its relevant metabolites were subjected to quantitation by using osteoblasts treated by YNB in vitro. It was found that YNB extract of 20 μg/mL could greatly activate the synthesis of intracellular prostaglandin E₂ and thromboxane B₂ in osteoblasts. Excretion of prostaglandin D₂ could be suppressed but not the thromboxane B₂. This study proved the efficacy of YNB on curing RA and its potential mechanism through modulating AA metabolism in osteoblasts to some extent.