Combination of the microalga <i>Pavlova</i> sp. OPMS 30543 with diclofenac attenuates hyperalgesia in adjuvant-induced arthritis mice

Marine microalgae, such as Pavlova spp, are known to produce bioactive compounds and have been extensively studied as natural resources with anti-inflammatory properties. Among several Pavlova spp, OPMS 30543 (Pav) has recently been found to contain a high fucoxanthin content. In this study, we aimed to evaluate the effects of Pav treatment on hyperalgesia using a mouse model of adjuvant-induced arthritis (AIA), which was established by injecting complete Freund's adjuvant. Pav alone did not suppress the hyperalgesia observed in AIA mice. However, combined with low-dose diclofenac (DFC; 0.1 mg/kg) resulted in marked analgesia. In AIA mice, the activation of excitatory neurons was observed in the spinal cord; however, this activation was suppressed by the combination of Pav and DFC. These findings suggest that Pav enhances the analgesic effect of DFC in a mouse arthritis-associated hyperalgesia, and may aid in the development of improved strategies for inflammatory pain management.