Effect of ibandronate on mitogen-activated protein kinase signaling pathway in rat models of osteoarthritis / 中国组织工程研究

ABSTRACT

BACKGROUND: Mitogen-activated protein kinase signaling pathway participates in the differentiation of osteoblasts and osteoclasts, closely related to subchondral bone reconstruction and play a key role in the occurrence and development of osteoarthritis. Bisphosphonates as bone resorption inhibitor is used to treat osteoporosis. OBJECTIVE: To observe the effect of sodium ibandronate on the knee osteoarthritis in rats, and changes of mitogen-activated protein kinase signaling pathway. METHODS: The study was approved by the Laboratory Animal Ethical Committee of the First Affiliated Hospital of South China University. Thirty female Sprague-Dawley rats were randomly divided into sham, model, and treatment groups. The rats in the latter two groups underwent ovariectomy bilaterally, and anterior cruciate ligament resection, and rats in the sham group received the fatty tissue surrounding the ovaries removed only. After 1 week of surgery, the rats in the treatment group were given intraperitoneal injection of 10 pg/kg sodium ibandronate, rats in the model group were injected with normal saline, and the sham group received no intervention. Twelve weeks late, the rats were killed to perform histological examination of cartticular cartilage and Mankin scores were detected. Micro-CT of subchondral bone and quantitative analysis of the bone microstructure were conducted. The protein and mRNA expression levels of extracellular signal regulated protein kinase and c-Jun N-terminal kinase in mitogen-activated protein kinase signaling pathway were measured. RESULTS AND CONCLUSION: (1) The cartilage structure in the model group was significantly damaged, the Mankin score was significantly higher than that in the sham group, and the Mankin score in the treatment group was significantly lower than that in the model group (P < 0.01). (2) The bone mineral density, trabecular bone volume ratio, trabecular number in the model group were significantly lower than those in the sham group (P < 0.01), and trabecular separation was higher than that in the sham group (P < 0.01). Compared with the model group, the treatment group had higher bone mineral density, trabecular bone volume ratio, trabecular number, and lower trabecular separation (P < 0.01). (3) The mRNA and protein expression levels of extracellular signal regulated protein kinase and c-Jun N-terminal kinase in the model group were significantly higher than those in the sham group (P < 0.05, P < 0.01), and the levels in the treatment group were significantly lower than those in the model group (P < 0.05). (4) To conclude, sodium ibandronate may inhibit subchondral bone loss and articular cartilage degeneration in rat models of osteoarthritis by inhibiting extracellular signal regulated protein kinase and c-Jun N-terminal kinase in mitogen-activated protein kinase signaling pathway.