ABSTRACT
Objective To observe the effect of dexamethasone(Dex)on the proliferation and os- teogenic differentiation of human marrow stromal cells(MSCs)in vitro.Methods The primary human MSCs were isolated and cultured by Ficoll seperation culture in vitro.In subcultures,human MSCs were respectively treated with dexamethasone 10~(-9),10~(-8) and 10~(-7) mol/L.The proliferation of human MSCs was measured using MTF method;cytoplasmic alkaline phosphatase(ALP)activity was measured;the osteogenic marker osteopontin (OPN)mRNA were examined by reverse transcriptase polymerase chain reaction(RT-PCR).Results The op- tical density values in cultures treated with dexamethasone 10~(-8) and 10~(-7) mol/L for 8 days were significantly lower than those in the controls(P＜0.05).Treatment of cells with Dex for 12 days led to a significant increase in cytoplasmic ALP activity(P＜0.05)in a dose-dependent manner.Dex induced OPN mRNA.Conclusion Dex inhibits the proliferation of human MSCs and dexamethasone 10~(-7) mol/L leads to a strong decrease in cell number.Dex induces human MSCs differentiate to osteoblastic cells.
ABSTRACT
Objective To investigate the effects of pulsed electromagnetic fields (PEMF) on osteogenic differentiation in demineralized bone matrix (DBM)-induced human marrow stromal cells (hMSCs).Methods hMSCs were obtained from iliac crest marrow aspirates of a healthy boy aged 14.Then 1?104 hMSCs per well were plated in 8 24-well tissue culture plates,and 1?105 hMSCs per well in 2 6-well plates after they were expanded until passage 2.Those 24-well plates and 6-well plates were divided into 4 groups,cell control group (C group),cell-material group (CD group),cell-PEMF group (CP group) and cell-material-PEMF group (CDP group).CD group and CDP group were added with one DBM (size of 5 mm?5 mm?3 mm),CP and CDP groups were exposed to the PEMF (frequency of 15 Hz,intensity of 5 Gs),and hMSCs were cultivated in subculture medium with full media exchange in every 3 d.Alkaline phosphatase (ALP) activity and osteocalcin (OC) level were performed at 1,7,14 and 21 d,and alizarin red staining and counting of calcium nodules were performed at 21 d.Results Significant differences in ALP activity and OC level were observed between cell control group and the other 3 groups in 7 d after treatment (P