Background
Facet joint osteoarthritis (FJOA) is a common lumbar osteoarthritis characterized by degeneration of small joint cartilage. Bushen Huoxue decotion (BSHXD) has good therapeutic effects on OA. Our work aimed to further probe the pharmacological effects of BSHXD-containing serum (BSHXD-CS) on FJOA and define underlying the mechanisms invovled.
Conclusion
BSHXD-CS inhibited NLRP3 inflammasome activation and pyroptosis in chondrocytes to repress OA progression by reducing RNA m6A modification.
Methods
To establish a FJOA cell model, primary rat chondrocytes were treated with LPS. The mRNA and protein expressions were assessed using qRT-PCR and western blot, respectively. The secretion levels of pro-inflammatory cytokines were measured by ELISA. Cell viability was determined by CCK8 assay. The global m6A level was detected by the kit, and NLRP3 mRNA m6A level was determined by Me-RIP assay. The molecular interactions were analyzed by RIP and RNA pull-down assays.
Results
BSHXD-CS treatment relieved LPS-induced cell injury, inflammation, NLRP3 inflammasome and pyroptosis in chondrocytes (all p < 0.05). LPS-induced NLRP3 upregulation in chondrocytes was related to its high m6A modification level (p < 0.05). It was also observed that BSHXD-CS reduced LPS-induced m6A modification in chondrocytes via repressing STAT3 (all p < 0.05), suggesting BSHXD-CS could repress NLRP3 expression via m6A-dependent manner. Moreover, DAA, a m6A specific inhibitor, was proved to strengthen the protectively roles of BSHXD-CS on LPS-challenged pytoptosis (all p < 0.05).