RESUMO
BACKGROUND:Cytological studies show that bone marrow mesenchymal stem cel s play an important role in postmenopausal osteoporosis mechanism. OBJECTIVE:To study the osteogenic differentiation in vitro of bone marrow mesenchymal stem cel s from ovariectomied osteoporotic rats. METHODS:The osteoporotic animal model was established by performing ovariectomy in the 6-month-old female Sprague-Dawley rats. There were four groups:bone marrow mesenchymal stem cel s control group, bone marrow mesenchymal stem cel s osteoporosis group, bone marrow mesenchymal stem cel s osteogenic induction group and oseogenesis induction group. Bone marrow mesenchymal stem cel s were isolated from the rats of control group and oseogenesis induction group by means of the whole bone marrow adherence method and cultured to the 3rd generation. Then the bone marrow mesenchymal stem cel s were used in al the experiments. Cel morphology was observed under the inverted phase contrast microscope, cel cycle and proliferation index of bone marrow mesenchymal stem cel s were detected by flow cytometry. After osteogenic induction, the expression level of alkaline phosphatase was detected, and the fornation of calcium nodes of bone marrow mesenchymal stem cel s were marked by alizarin red staining. RESULTS AND CONCLUSION:The cel s in the osteogenic induction group and oseogenesis induction group had the morphology of osteobalsts, and the change of morphology of the cel s in the oseogenesis induction group was relatively tardiness. The proliferation index in the control group was higher than that in the osteoporosis group (P<0.05);expression level of alkaline phosphatase in the osteogenic induction group was significantly higher than that in the oseogenesis induction group (P<0. 05), and the control group was significantly higher than the oseogenesis group (P<0.05). The alizarin red staining of the cel s in the osteogenic induction group was positive, while negative in the control group and the oseogenesis group;the staining in the osteogenic induction group was stronger than that in the oseogenesis induction group. These findings indicate that both the proliferative potential and the osteogenic potential of bone marrow mesenchymal stem cel s from the ovariectomized osteoporotic rats are decreased, which may be related with the ostoeporosis pathogensis of ovariectomied rats.
RESUMO
BACKGROUND: Vascular endothelial growth factor play an important role in promoting healing of osteoporotic fractures, but whether it can affect the bone mineral density is not clear. OBJECTIVE: To observe the correlation between serum vascular endothelial growth factor, bone mineral density and the number of osteoblasts in the ovariectomized rats. METHODS: Forty female Sprague-Dawley rats were randomly divided into ovariectomized group and control group. After 3 months, the bone mineral density of the whole body, femur and lumbar spine was measured. Rat enzyme-linked immunosorbent assay kit was used to measure the level of serum vascular endothelial growth factor. Then, the rats in two groups received femoral metaphyseal fixation, decalcified, dehydrated, embeding in paraffin, slicing and hematoxylin-eosin staining. Each slice was free to take five fields of view (10×40) in order to count the osteoblasts of femur distal metaphysis under optical microscope. RESULTS AND CONCLUSION: After ovariectomized for 3 months, the rats body mass was increased significantly (P 0.05), and the difference of the osteoblast number between ovariectomized group and control group was not significant (P > 0.05). This indicated that there was no correlation between bone mineral density and the number of osteoblasts and vascular endothelial growth factor level in the ovariectomized group and the control group. These findings suggest that the bone mineral density is reduced and the body mass is increased in the ovariectomized rats, and the reduced bone mineral density of ovariectomized rats may be irrelevant with the change of serum vascular endothelial growth factor.