Rspo1 inhibited apoptosis of glucocorticoid-induced osteoblasts via Wnt/β-catenin pathway in Legg--Calve--Perthes disease.

Background. The pathogenesis of Legg--Calve--Perthes disease (LCPD), a juvenile form of avascular necrosis of the femoral head (ANFH), is not fully understood. Objectives. The purpose of this work was to study the regulatory effect of R-spondin 1 (Rspo1) on osteoblastic apoptosis and evaluate the pre-clinical efficacy of recombinant human protein Rspo1 (rhRspo1) in treatment of LCPD. Materials and methods. This is an experimental study. In vivo rabbit ANFH model was established. Human osteoblast cell line hFOB1.19 (hFOB) was used to overexpress and silence Rspo1 in vitro. Additionally, hFOB cells were induced with glucocorticoid (GC) and methylprednisolone (MP), and treated with rhRspo1. The expres- sions of Rspo1, β-catenin, Dkk-1, Bcl-2, and caspase-3, and the apoptosis rate of hFOB cells were examined. Results. The expressions of Rspo1 and β-catenin were lower in ANFH rabbits. The expression of Rspo1 was decreased in GC-induced hFOB cells. Compared to the control group, after 1 μM MP induction for 72 h, the expressions of β-catenin and Bcl-2 were higher, while Dkk-1, caspase-3 and cleaved caspase-3 expressions were lower in Rspo1 overexpression and rhRspo1-treated groups. The apoptosis rate of GC-induced hFOB cells was decreased in Rspo1 overexpression and rhRspo1-treated groups compared to the control group. Conclusions. R-spondin 1 inhibited GC-induced osteoblast apoptosis via Wnt/β-catenin pathway, which might be associated with the development of ANFH. Moreover, rhRspo1 had a potential pre-clinical therapeutic effect on LCPD. [ABSTRACT FROM AUTHOR]