ABE treatment regulates the RANKL/RANK/OPG signaling pathway in rats with steroid-induced ONFH. RANK, RANKL, and OPG levels in the serum of rats with steroid-induced ONFH with or without ABE treatment were detected by ELISA (A). RANKL, RANK, and OPG expression in the femoral heads of rats with steroid-induced ONFH with or without ABE treatment were detected at mRNA and protein levels by quantitative real-time RT-PCR (B), western blot (C), respectively. (D) shows the ratio of RANKL/OPG in the serum, the ratio of RANKL mRNA/OPG mRNA, and the ratio of RANK protein/OPG protein in the rats with steroid-induced ONFH with and without ABE treatment. Data are presented as the mean ± S.D. (n =20 for control, n =25 for model, n =20 for ABE treatment groups). ##: P <0.01, in comparison with the control group. * and **: P <0.05 and P <0.01, respectively, in comparison with the model group.