| Objective To investigate the effect of corticosterone on the expression of sterol modulates the element binding protein (SREBP1), SREBP2, 3-hydroxy-3-methyl malonate coenzyme A reductase (HMGCR), and fatty acid synthase (FAS) in rat osteoblasts in vitro, and the effect of this change on lipid accumulation in the cells. Methods Osteoblasts from the skull of newborn SD rats with collagenase digestion method were research objects. The lipid accumulation characteristics and the gene and protein expressions of SREBP1, SREBP2, HMGCR, and FAS after addition of corticosterone in osteoblasts were observed. Results The Nile red lipid staining in the cells increased gradually with time after addition of corticosterone. With same concentration of corticosterone, the staining was not changed at 24h, 48h, and 72h. The gene and protein expressions of SREBP1, SREBP2, HMGCR, and FAS increased in 24h, but decreased in 48h and 72h, after addition of different concentrations of corticosterone. When additioned with 1μmol/L of corticosterone, the expressions of SREBP1, SREBP2, HMGCR, and FAS increased in 24h, but were constant in 48h comparing with control group. In 72h, the expressions of SREBP1 and FAS decreased, the expression of SREBP2 increased, and the expression of HMGCR was constant. Conclusion Over physiological dose of corticosterone induces abnormal accumulation of lipids in osteoblasts. Different concentrations of corticosterone stimulate the gene and protein expressions of SREBP1, SREBP2, HMGCR, and FAS in osteoblasts in 24h. |