The effect of admixture of vitamin D(3) and dexamethasone on the activity of osteoblastic cells

Lim, Na Won; Park, Young Joo; Kim, Sang Cheol

Abstract

Bone is a dynamic tissue which is constantly remodelled by subsequent cycles of bone resorption and formation. Glucocorticoid and vitamine D3 are known as regulating substances in bone metabolism. In vitro experiments using bone tissue, it was suggested that glucoccorticoid inhibits bone resorption, whereas the effect of glucocorticoid on bone formation are complex- increasing or decreasing effect. The active form of vitamin D3, 1,25-dihydroxycholecalciferol [1.25-(OH)2D3], has been reported to stimulate osteoblastic activities including the production of ALP, type I collagen, and osteoclacin. The purpose of this study was to evaluate the effect of admixture of vitamin D3 and dexamethasone, one of glucocorticoids, on osteblastic cell line(MC3T#-E1). Alkaline phosphatase(ALP) and MTT assay were conducted in the cultivated cells with 1, 10, 100nm/ml of 1,25-(OH)2D3 and/or 10nM/ml, 100nM/ml, 1micrometer/ml of dexamethasone. The observed results were as follows. 1. The activity of osteoblastic cells with 1micrometer/ml of dexamethasone was significantly increased at 1-day cultivation with comparison to control group, but was decreased afterwards. But the activity of ALP was greatest in 1micrometer/ml of dexamethasone and increased with time lapsed. 2. The activity of osteoblastic cells with vitamin D3 was significantly increased dose-dependently at 1-day cultivation, but was significantly decreased in 10nM/ml or 100nM/ml at 2-day or 3-day cultivation, and was greatest in 100nM/ml at 3-day cultivation. 3. In case of admixture of dexamethasone and vitamin D3 at 2-day cultivation, but was increased again at 3-day cultivation, which was greater than that in control or dexamethasone only group. The activity of ALP was decreased at 1-day cultivation, but was increased in the admixture of 10nM/ml or 100nM/ml of dexamethasone with 100nM/ml of vitamin D3 at 2-day cultivation, and was again decreased at 3-day cultivation.