Xibining inhibition of the PI3K-AKT pathway reduces M1 macrophage polarization to ameliorate KOA synovial inflammation and nociceptive sensitization

BACKGROUND: Pain is the most critical symptom of knee osteoarthritis(KOA), which seriously affects the quality of life of patients. Xibining (XBN), a traditional herbal compound, has achieved good results in the clinical treatment of KOA, and its mechanism of action is worth exploring in depth. OBJECTIVE: In vivo and in vitro models of KOA were constructed, and the potential drug action mechanism of XBN in improving osteoarthritis pain was explored in combination with transcriptomics. METHODS: In vitro experiments were also conducted to explore the effects of different treatments of BMDMs on TRP channels in DRG neurons by constructing a coculture system of BMDMs and DRG neurons. The specific mechanism by which XBN affects BMDMs was explored via participatory transcriptomics. RESULTS: Our results showed that KOA aggravated macrophage infiltration in synovial tissues and DRG tissues and increased the transcriptional and translational levels of TRPA1, TRPV1, and TRPM8 in synovial tissues and DRG tissues; XBN treatment improved inflammation in synovial tissues and macrophage infiltration in DRG tissues, and it decreased the transcriptional and translational levels of TRPA1, TRPV1, and TRPM8, consistent with the results of behavioral tests to improve nociceptive sensitization induced by KOA. The results from in vitro experiments showed that promoting macrophage M1-type polarization exacerbated TRP channel activation in DRG neurons and that XBN acted by inhibiting macrophage M1-type polarization. A reference transcriptome study showed that XBN may play a role in inhibiting M1 macrophage-type polarization in KOA by suppressing the PI3K-AKT pathway in BMDMs. We verified the conclusions obtained from transcriptomics via in vitro experiments. We place greater emphasis on the role that the intrinsic immune system plays in the area of pain control in osteoarthritis. CONCLUSION: XBN improve KOA nociceptive sensitization by modulating the PI3K/Akt signaling pathway, attenuating the level of synovial inflammation and inhibiting M1-type macrophage polarization in synovial and DRG tissues in KOA mice.