Sildenafil promotes the osteogenic differentiation of rat bone marrow stromal cells in vitro

Aim To investigate the effects of sildenafil on the proliferation and osteogenic differentiation of rat bone marrow stromal cells(rBMSCs).Methods The rat bone marrow sample was obtained,and rBMSCs were cultured using adherence screening methods.The culture medium was replaced every three days.Nine days later,serial subcultivation proceeded.Sildenafil spplemented into the culture at 1×10-4,1×10-5,1×10-6,1×10-7mol·L-1 respectively.MTT method was adopted in proliferation analysis.The activity of ALP was examined after induced 9 days.Search the best concentration and supplemented into the medium,then the osteogenic differentiation markers including mineralized bone nodules,CFU-FALP were compared between the sildenafil-supplemented group and the control.Total RNA was isolated and the gene expression of Runx-2 and Osterix was investgated by RT-Real Time PCR.The total protein was also isolated and the secre-tion of collagenⅠ was examined by Western blot.Results The proliferation of rBMSCs was refrained by sildenafil dose-dependently.But it evidently led was to osteogenic process.1×10-5mol·L-1 was the best concentration.Sildenafil improved the secretion of collagen Ⅰ,CFU-FALP amounts and mineralized nodules significantly.Besides,it also could enhance the mRNA level of Runx-2 and Osterix.Conclusions The sildenafil with final concentration of 1×10-5mol·L-1 enhances the osteogenic differentiation of rBMSCs significantly,suggesting that sildenafil not only has other pharmacologic actions,but also has the activity of antiosteoporosis.It has the potential to be developed into a new drug of anti-osteoporosis.