Experimental study:the effect of dexamethasone on the adult osteoblast proliferation and differentiation

Objective To observe and analyze the effect of dexamethasone on the adult osteoblast proliferation and differentiation in vitro. Methods Iliac trabecular bone specimens were obtained from eight adult patients undergoing scheduled surgery. After the bone pieces were treated with collagenase trypsin, larage numbers of osteoblasts were released out. Then the osteoblasts were purified and their passages were fed with DMED-F12 and fetal bovine serum. The cells were incubated under the condition of 37 ℃, 95% relative humidity and 5% CO2. Subsequently, 1×10-8 mol/L dexamethasone were added into culture medium to feed eight groups of osteoblasts for three days and the control groups were cultured not to add medicine at the same time. All the groups were observed continually under light microscope and transmission electron microscope. Finally, apoptosis detection was performed by use of the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and biochemical indexes alkaline phosphatase (ALP) and osteocalcin (OCN), were assayed to check if dexamethasone has any effect on proliferation and differentiation of osteoblasts in vitro. Results Of the adult osteoblasts obtained by collagenase trypsin method, the survival condition was good, the biochemical indexes were stable, the degree of purification was excellent, and they were fit for the next step study. The following data demonstrated that under the condition of dexamethasone 1×10-8 mol/L and osteoblasts 10 000 /ml, there were significant increase of ALP and OCN secretion without apoptosis alteration. Conclusion Dexamethasone has significant promoting effect on proliferation and differentiation of adult osteoblasts in vitro without apoptosis alteration and could be used as positive control during screening research of osteoporosis.