Background
Knee osteoarthritis (KOA) is a chronic progressive osteoarthropathy. Chrysin's anti-KOA action has been demonstrated, however more research is needed to understand how chrysin contributes to KOA.
Conclusion
Chrysin mitigated neuropathic pain and peripheral sensitization in KOA rats by repressing the RAGE/PI3K/AKT pathway modulated by HMGB1.
Methods
LPS/ATP-induced macrophages transfected with or without HMGB1 overexpression underwent 5 μg/mL chrysin. The cell viability and macrophage pyroptosis were examined by cell counting kit-8 and flow cytometer. In vivo experiments, rats were injected with 1 mg monosodium iodoacetate by the infrapatellar ligament of the bilateral knee joint to induce KOA. The histological damage was analyzed by Safranin O/Fast Green staining and hematoxylin and eosin staining. The PWT, PWL and inflammatory factors were analyzed via Von-Frey filaments, thermal radiometer and ELISA. Immunofluorescence assay examined the expressions of CGRP and iNOS. The levels of HMGB1/RAGE-, NLRP3-, PI3K/AKT- and neuronal ion channel-related markers were examined by qPCR and western blot.
Results
Chrysin alleviated macrophage pyroptosis by inhibiting HMGB1 and the repression of chrysin on HMGB1/RAGE pathway and ion channel activation was reversed by overexpressed HMGB1. HMGB1 facilitated neuronal ion channel activation through the RAGE/PI3K/AKT pathway. Chrysin could improve the pathological injury of knee joints in KOA rats. Chrysin suppressed the HMGB1-regulated RAGE/PI3K/AKT pathway, hence reducing KOA damage and peripheral sensitization.