Sanmiao wan alleviates inflammation and exhibits hypouricemic effect in an acute gouty arthritis rat model

Ethnopharmacological relevance: Sanmiao wan (SMW), a classical traditional Chinese medicine (TCM) formula, has been employed to treat gouty diseases in clinic as early as Yuan dynasty. It shows remarkably therapeutic effects in acute gouty arthritis (GA). However, the potential mechanisms of SMW are still not fully revealed. Aim of the study: The objective of this project is to evaluate the pharmacological effects and possible mechanisms of SMW in a rat model of acute GA. Materials and methods: Monosodium urate (MSU) suspension was injected into the ankle joint of rats to establish acute GA model. The inflammation was evaluated by measuring the posterior ankle diameter. The pathological status of synovial tissue was assessed by hematoxylin eosin (HE), Masson, and picrosirius red staining. The level of IL -6 was measured using ELISA kit. The levels of blood urea nitrogen (BUN), creatinine (CR), UA (uric acid), and xanthine oxidase (XOD) in the serum were measured using standard diagnostic kits. The percentage of Th17 cells in blood samples was performed using flow cytometry. Moreover, RT-qPCR was performed to examine the mRNA level of RANK, ROR gamma t, RANKL, and STAT3 in the synovial tissue. Furthermore, immunofluorescence was carried out to assess the expression of STAT3 in the synovial tissue. Results: SMW effectively alleviated the inflammation and improved the pathological status of the ankle joint in rats with acute GA. It significantly suppressed the release of proinflammatory cytokine (IL -6). Meanwhile, the levels of UA, BUN, and CR were markedly reduced after SMW treatment. A remarkable reduction of XOD activity was observed in the study. Importantly, SMW treatment significantly reduced the frequency of Th17 cells, decreased the mRNA levels of RANK, ROR gamma t, RANKL, and STAT3 in the synovial tissue. Furthermore, the suppression of STAT3 was also demonstrated using immunofluorescence in SMW-treated group. Conclusion: SMW showed significant anti-inflammatory and hypouricemic effects in a rat model of GA. It is an effective TCM formula for GA therapy.