title: Effect of mechanical stretch on the proliferation and differentiation of BMSCs from ovariectomized rats.
abstract: Osteoporosis is characterized by a broken balance between bone formation and bone resorption. Mechanical stress has been considered to be an important factor in bone modeling and remodeling. However, biological responses of stromal cells in osteoporosis to mechanical stimuli remain unknown. To explore the correlation between mechanical stress and osteoblastic differentiation of bone mesenchymal stem cells (BMSCs) in osteoporosis, we built an osteoporosis model in ovariectomized (OVX) rats, and then investigated proliferation, alkaline phosphatase (ALP) activity, and the expression of osteoblastic genes in BMSCs under mechanical stress of 5 and 10% elongation, using the Flexercell Strain system. The proliferation of BMSCs was detected using alamarBlue. The expression of osteoblastic genes was analyzed by real-time quantitative polymerase chain reaction. Protein expression was examined by Western blotting. BMSCs (OVX) and BMSCs (Sham-operated, Sham in short) proliferations were inhibited at 5 and 10% elongation at day 3, compared with the un-stretched group, while BMSCs (OVX) proliferation was slower than BMSCs (Sham). ALP activity increased significantly at 10% elongation in both cells, but it was less active in BMSCs (OVX) than BMSCs (Sham). At days 3 and 7, the mRNA expression of osteoblastic genes was unregulated by mechanical stretch (5 and 10 % elongation); however, osteoblastic gene expression in BMSCs (OVX) was less than that in BMSCs (Sham). The mRNA and protein expression of Runx2 showed similar trends in BMSCs (OVX) under mechanical stretch. These results indicate that the mechanical stretch stimulates osteoblastic differentiation of BMSCs (OVX); however, this differentiation was weaker than that of BMSCs (Sham).
authors.affiliation: Center of Craniofacial Orthodontics, Department of Oral and Cranio-maxillofacial Science, Shanghai Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine, Room 405, Building 1, No. 639, Zhi Zao Ju Road, Shanghai, 200011, People's Republic of China.
authors.forename: Yuqiong
authors.initials: Y
authors.lastname: Wu
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Qinggang
authors.initials: Q
authors.lastname: Dai
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.forename: Runqing
authors.initials: R
authors.lastname: Fu
authors.forename: Lingyong
authors.initials: L
authors.lastname: Jiang
authors.forename: Bing
authors.initials: B
authors.lastname: Fang
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000201:enzymology; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics; D010052:Ovariectomy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D012333:RNA, Messenger; D000469:Alkaline Phosphatase