Tetrahydropalmatine attenuates MSU crystal-induced gouty arthritis by inhibiting ROS-mediated NLRP3 inflammasome activation

Activation of NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome plays a crucial role in the inflammatory responses of monosodium urate (MSU) crystal-induced gouty arthritis. Therefore, the molecular basis of NLRP3 inflammasome is very valuable in developing potential therapeutic drugs for gout. Tetrahydropalmatine (THP), the main active component of the traditional Chinese medicinal herb Corydalis yanhusuo, has shown prominent anti-inflammatory and analgesic activities, but to date, these effects have not been investigated exhaustively on gout. This study indicated that THP attenuated pain and swelling in an MSU-induced acute gout model by decreasing pro-inflammatory cytokine production and inflammatory cell infiltration. THP exerted its actions by suppressing NLRP3 inflammasome activation and subsequent formation of Caspase-1. Furthermore, results showed that THP alleviated MSU-induced Reactive Oxygen Species (ROS) generation, upstream of NLRP3 inflammasome activation, by an increase in the activities of antioxidant enzymes both in vitro and in vivo. In conclusion, our study suggests that THP suppressed ROS-mediated NLRP3 inflammasome activation in MSU-induced inflammatory responses, which highlights its therapeutic potential in gouty arthritis.