In clinic, strontium ranelate (SrR) is a useful drug to treat osteoporosis by orally taken method, but some side effect appeared in recent years. The aim of this study is to evaluate the effectiveness and safety of SrR on cells by direct application, to study the possibility of local application of this drug. Qualitative ALP staining, quantitative ALP activity assay, alizarin red staining, realtime PCR and westernblot assay were used to evaluate the osteogenesis ability of SrR under normal or osteogenic induction environment of ovariectomy bone marrow mesenchymal stem cells (OVX-BMSCs). The angiogenesis ability of SrR was studied by immunofluorescence staining of CD31 and vWF of OVX-BMSCs under angiogenesis induction environment, transwell, tubeformation and realtime PCR assay of HUVECs. Signaling pathway of PI3K/AKT/mTOR was also studied. The result demonstrated that SrR could enhance proliferation and osteogenic differentiation of OVX-BMSCs. The osteogenesis effect of SrR has been proved by the better performed of ALP activity, alizarin red staining and the remarkable up-regulation of ALP, Col-I, Runx2, OCN, BMP-2, BSP, OPG of the OVX-BMSCs, and reduction of RANKL. In addition, SrR promotes angiogenesis differentiation of both OVX-BMSCs and HUVECs. Higher intensity of immunostaining of CD31 and vWF, better result of transwell and tubeformation assay could be observed in SrR treated group, and increasing mRNA levels of VEGF and Ang-1 in the OVX-BMSCs, VEGF in HUVECs were learnt. Signaling pathway assay showed that PI3K/AKT/mTOR signaling pathway was involved in this SrR triggered angiogenesis procedure. The thrombosis marker ET-1, PAI-1 and t-PA were up-regulated, but no significant differences for low concentration (<0.5mM). The concentration between 0.25-0.5mM may be more appropriate for local application, and locally application of SrR could be considered as a promising way for bone regeneration.

Strontium ranelate (SrR) is an anti-osteoporosis drug with excellent osteogenic and angiogenic capacity. In this study, we aimed to investigate the osteogenesis and angiogenesis effects of SrR and the underlying mechanism involved. RNA-Seq was conducted to examine the effects of SrR on gene expression in ovariectomy rat bone marrow mesenchymal stem cells (OVX-rBMSCs). To validate the different expressed gene in vitro, the effects of gene interference and overexpression in osteogenic induction environment of OVX-rBMSCs and in primary osteoblasts were studied. RNA-Seq showed that ROCK1 significantly increased after SrR treatment in OVX-rBMSCs, and further validated by real-time PCR and western blotting. Overexpression of ROCK1 promoted osteogenic differentiation of OVX-rBMSCs and induced cell viability and inhibited apoptosis of primary osteoblasts, which was reversed by inhibition of ROCK1 by RNA interference or ROCK1 inhibitor (Y-27632) after SrR treatment. Furthermore, the SrR was loaded on nano-structured hydroxyapatite (nano-HAp) particulates to promote osteogenesis and angiogenesis in repairing of the femoral condyle bone defect using ovariectomy rat model. Taken together, ROCK1 is one of the targets that SrR promotes the osteogenic differentiation of OVX-rBMSCs and cell viability of primary osteoblasts, the nano-HAp particles could act as carriers for SrR to repair bone defects.

These findings indicate that CMMA is an effective way to achieve a balance between airway enlargement and facial appearance for Chinese patients with severe OSA.