Study Of The Effects Of 17β-estradiol On Osteoprogenitors From Periosteum

BackgroundLoss of ovarian function at menopause represents the most important factor for the development of menopausal osteoporosis. Due to the aging population, the metabolic bone disease that affects millions worldwide and contributes considerably to the morbidity and mortality among elderly women. Until recently, the molecular mechanism of estrogen on the pathogenesis of osteoporosis has not been clear. Research on the effects of estrogen on bone formation has been focused on the bone marrow mesenchymal stem cells which are only one source of osteoprogenitors. The other important source of osteoprogenitors from periosteum is neglected.In clinical trials, we found the intact periosteal sheath is very important for fracture healing. In 2003, Ahlborg and colleagues report an association between the extent of endocortical resorption and periosteal apposition during 15 years after menopause. Women with greater endocortical bone loss had greater periosteal bone formation. The cortical thickness was undiminished. The cortex was displaced outward, maintaining or slightly increasing the cross-sectional area of the bone and reducing the age-related decrease in bone mass and strength. Bone strength depends on material properties, such as tissue mineral content and bone mass density. Certain structural characteristics of the skeleton-for example, size, shape, and the three-dimentional architecture-also affect bone strength. Since periosteal bone formation can increase bone size, it must be a neglected determinant of bone strength. All these advance our thinking and the therapeutic options available for the prevetion and treatment of bone fragiliy. Given the unique biomechanical advantage of the deposition of bone on the periosteal surface, the periosteal-linning cell is an obvious target for drug therpy.Objective1.To establish rat calvaria periosteum-derived osteoprogenitors as in vitro culture model for studying periosteal bone formation.2.To explore the effects of different concentrations of 17p-estradiol on proliferation of periosteum-derived osteoprogenitors .3. To explore the effects of different concentrations of 17P-estradiol on the mRNA expression level of different function-associated genes of periosteum-derived osteoprogenitors.4.To construct the differently expressing genes library of human periosteal cells between estrogen and control treatment to study the regulating effect of estrogen on periosteal cells and searech for the target genes regulated by estrogen.