WENYANGBUSHEN-INDUCED-EXPRESSION OF VEGF, OPG, RANK, AND RANKL IN RABBITS WITH STEROID-INDUCED FEMORAL HEAD AVASCULAR NECROSIS

This study was aimed to investigate the effects of Wenyangbushen formula on the mRNA and protein expression of VEGF, OPG, RANK, and RANKL in the steroidinduced avascular necrosis of the rabbit femoral head (SANFH) and to further explore the potential mechanism of this formula on the treatment of SANFH. One hundred and thirty six New Zealand rabbits were randomly divided into 5 groups (n = 24 rabbits in each group): normal group, model group, Traditional Chinese Medicine (TCM) Wenyangbushen decoction at low, moderate and high dose group. The normal group and positive control group were intragastrically (i.g.) administered with saline. The TCM group was treated with Wenyangbushen decoction at the indicated dosage. After treated for eight weeks, the mRNA and protein expression of VEGF, OPG, RANK, and RANKL in the femoral head tissues was determined by RT-PCR and Western blotting, respectively. Wenyangbushen decoction treatment can effectively promote bone cells, osteoblasts and chondrocytes growth, as well as prevent the cell apoptosis in SANFH. The mRNA and protein expression of OPG and VEGF was increased while the levels of RANK and RANKL were reduced in the necrotic tissue of model group compared with those in the normal rabbits. And Wenyangbushen treatment prevented those changes, as manifested by up-regulation of VEGF and OPG, while down-regulation of RANK and RANKL levels in a dose-dependent manner. Wenyangbushen Formula treatment can alleviate necrosis of femoral head induced by steroid. It can promote bone cells, osteoblasts and chondrocytes growth, as well as prevent the cell apoptosis. Meanwhile, it up-regulates OPG and VEGF while inhibits RANK and RANKL expression. This may be one of the mechanisms for the effective treatment of SANFH.