Proliferation and differentiation of bone marrow mesenchymal stem cells in process of bone loss in ovariectomized rats

AIM:To study the function of proliferation and differentiation of bone marrow mesenchymal stem cells(BMSCs) for bone loss in the pathogenesis of osteoporosis(OP) in ovariectomized rats.METHODS:Animal model of OP was established by ovariectomy(OVX,bilateral ovarian resection) in 10-week-old healthy female Sprague-Dawley (SD) rats.BMSCs were isolated,cultured and purified by the combination of density gradient centrifugation,adhesion separation and limited dilution method,and cultured in vitro to the 3rd～4th passage in all experiments.The BMSCs phenotype appraisal was studied by flow cytometry.Colony-forming assay was applied to detect the BMSCs proliferation ability. The MTT method was used to analyze the growth curves of BMSCs.After adipogenic induction(ADI),lipid drops were observed by oil red 0 staining to compare the adipogenic potential between the 2 kinds of BMSCs.After osteogenic induction (OSI),calcium nodules were observed by alizarin red staining(ARS).The mRNA expression levels of BMSCs osteogenesis-related proteins,for instance,Runx2,osteocalcin(OCN) and osteopontin(OPN ) were measured by RT-PCR. RESULTS:Compared with sham group,the colony-forming ability of BMSCs in OVX group became decreased,the proliferation capacity was declined,the osteogenic potential was decreased,and the adipogenic potential was increased (P 0.05).CONCLUSION:In ovariectomized OP rats,the proliferation and osteogenesis of BMSCs decrease,and the adipogenesis of BMSCs increases,which may cause rapid bone loss and play an important role in the pathogenesis of OP.