[Effects of glucose and insulin in the cell differentiation from bone marrow stem cells to osteoblasts]

To observe the effects of different concentrations of glucose and insulin in cell differentiation from bone marrow stem cells (BMSC) into osteoblasts (OB) and explore the acting mechanism of glucose and insulin in bone metabolism.

The in vitro technique of cell culture was employed to separate, purify and cultivate BMSC from the tibia and femur of rats. Then the BMSCs were differentiated into osteoblasts under the inductions of different glucose concentrations (5.6, 25, 50 mmol/L) with or without the addition of insulin (0.6 microg/ml). Later the calcium nodule cell ratio of osteoblasts in alizarin red stain was observed microscopically to assay the mRNA expression of OB markers-ALP, BGP and Runx2 by real-time PCR.

With the increasing glucose concentrations, the number of red calcium nodules obviously decreased. PCR showed that the mRNA expression of ALP, BGP and transcription factor Runx2 decreased too. The difference was significant (P < 0.05). The differentiation of OB decreased with with the increasing glucose concentrations. The cell number of red calcium nodules obviously increased in the same glucose concentration groups. The mRNA expression of ALP, BGP and Runx2 also increased (P < 0.01). It hinted that insulin could enhance the differentiation of OB.

Glucose can inhibit the differentiation from BMSC into OB. The inhibition is more sensitive along with the concentration increments. This may be one of the pathogenesises of diabetic osteoporosis. Insulin can enhance the differentiation from BMSC into OB. In addition, it can improve the inhibition of differentiation from BMSC into OB because of a high concentration of glucose.