The Effect of Glucocorticoid-induced Osteoporotic Conditions on Osteoblast Cell Adhesion

Glucocorticoids (e.g. dexamethasone, DEX) have been shown to repress osteoblast (OB) function. These changes lead to glucocorticoid-induced osteoporosis, via reduced bone formation (Patschan et al, 2001).Studies have shown that osteoporotic OB do not attach and spread well to their extracellular matrix as compared to non-osteoporotic cells (Perinpanayagam et al, 2001). Objectives: The goal of this study was to determine a protocol for pre-treating MC3T3-E1 cells in-vitro with DEX to cause glucocorticoid-induced osteoporosis, and to determine a quantitative basis of cellular attachment of these osteoporotic cells to tissue culture plastic (TCP). Methods: MC3T3E1 OBs were cultured in the presence of DEX to induce osteoporotic-like conditions to the cell culture. OBs were cultured in two concentrations of DEX (10-6M, 10-7M), and for three different time periods (24h, 48h, 96h). OB cellular attachment (CA) assays on TCP were used to determine the effect of the different DEX treatments on CA properties. Results: OB CA was significantly greater (p<0.05) with non-treated cultures (92%) as compared to a reduction in CA with DEX treated OB after 24h (72%) 48h (63%) and after 96h (53%) of culturing respectively. Assays also demonstrated that DEX treated OB were viable and continued to proliferate, but at a slower rate when compared to non-treated OB, suggesting that the reduction in CA was not due to lack of proliferation or cell death. Conclusions: These findings demonstrate DEX treated OBs attach less readily to TCP when compared to non-treated OBs. Therefore, the protocol used in this study for pre-treating MC3T3E1 cells in-vitro with DEX caused a glucocorticoid-induced osteoporosis-like suppression of OB function. With the ability to cause glucocorticoid –induced osteoporosis with DEX in vitro, a quantitative basis of cellular attachment of these osteoporotic cells to different implant surfaces can be studied. Support: NIH/NIDCR T35 DE07159-18 (BK), P60 DE13076-04 (GBS, JCK).