Effect of glucocorticoid on differentiation of bone marrow mesenchymal cells / 中国组织工程研究

ABSTRACT

BACKGROUND:Lipopexia induced by glucocorticoid is fat precipitation in marrow due to abnormal lipomatabolism,or differentiation of cells resulting from hormone-affected bone marrow mesenchymal cells.The precise generating procedure remains unclear.OBJECTIVE:To Jnvastigate effects of vadous concentrations of dexamethasone on adipogenic differentiation of bone marrow mesenchymal cells.DESIGN,TIME AND SETTING:The observational study was performed at the Department of Biochemistry,China Medical University from January 2007 to January 2009.MATERIALS:A total of 80 Sprague-Dawley rats aged 3 or 4 weeks,weighing (110±10) g,of both genders,were used in this study.METHODS:Rat bone marrow mesenchymal cells were isolated and subcultured.Bone marrow masenchymal cells at the third passage were used as samples.MAIN OUTCOME MEASURES:Cellular morphologic changes after treatment of 10~(-7) mol/L dexamethasone were observed under an inverted microscope,as well as at 3,7,14 and 21 days under normal culture condition.Morphological changes of bone marrow mesenchymal cells were observed following alkaline phosphatase and Sudan Ⅲ staining.Alkaline phosphatase activity was measured using phenol reagent.Effects of dexamethasone on cell proliferation were measured using MTT assay.RESULTS:Following 24 hours of incubation,a few adherent cells were found in the bottom of the culture flask,showing spindle shape.With prolonged time,adherent cells became more,presenting radiated shape.Following passage,cells distributed uniformly,showing typical fibroblast-shape.Following dexamethasone stimulation,cells changed from spindle-shape into polygonal or irregular shape.In the late phase,with increased concentration and prolonged time,cell colonies disappeared;cells adhered,and died.In normal cultured cells,no or a few orange particles were found.In dexamethasone-cultured cells,with increased hormone concentration and prolonged time,Sundan Ⅲ stained particles increased.At 21 days,alkaline phosphatase activity under normal culture was separately 1.57-,4.49-and 5.0-fold of 10~(-8),10~(-7),10~(-6) mol/L dexamethasone group.At 7,14 and 21 days,alkaline phosphatase activity under normal culture was separately 2.93-,3.80-and 4.39-fold of 10~(-7) mol/L dexamethasone group (P ＜ 0.05).High concentration of dexamethasone had significant inhibitory effects on cell proliferation activity.Significant difference was detected as compared 10~(-7) mol/L and 10~(-6) mol/L to other groups (P ＜ 0.05).CONCLUSION:High-dose dexamethasone enhances adipogenic and suppresses osteoblastic differentiation of bone marrow mesenchymal cells.The effect will increase along with the increasing content and prolonged duration of demamethasone stimulation.