Mechanism of Gugutou Huaisiyu Capsule in alleviating peripheral pain sensitization in rats with steroid-induced osteonecrosis of the femoral head

• Gugutou Huaisiyu Capsule significantly improves bone microstructure and increases mechanical pain threshold in rats with steroid-induced osteonecrosis of the femoral head. • The capsule reduces serum levels of pain mediators CGRP and substance P, indicating a systemic analgesic effect. • It downregulates the expression of TrkA, CGRP, and β3-tubulin in the femoral head and dorsal root ganglion, suggesting inhibition of neuronal sensitization. • The therapeutic mechanism may involve suppression of TrkA-mediated signaling pathways, providing a potential target for pain management in osteonecrosis.