Dendrobine Ameliorates Glucocorticoid-Induced Osteoporosis by Promoting Osteogenesis through JNK/p38 MAPK Pathway Activation and GR Nuclear Translocation Inhibition

Glucocorticoid-induced osteoporosis (GIOP) is the common reason for secondary osteoporosis. Dendrobine (DEN) is the major biologically active component of Dendrobium officinale with anti-inflammatory and antiaging properties. Whether DEN could alleviate osteogenic inhibition in GIOP rats is still unknown. The influence on osteogenic function caused by DEN on dexamethasone-treated bone marrow mesenchymal stem cells and rats was observed. The in vitro results showed that DEN reversed the inhibition of osteogenic differentiation by dexamethasone. Moreover, DEN supplementation attenuated dexamethasone-induced bone loss in vivo. DEN activated JNK and p38 MAPK pathways and restrained GR nuclear translocation, which could be prevented by the JNK (SP600125) or p38 (SB203580) pathway inhibitor. This study verified that DEN alleviated dexamethasone-induced nuclear translocation of GR, and inhibition of osteogenesis via JNK and p38 pathways, laying the foundation for DEN as a therapeutic agent for GIOP.