| 2089 Proliferation and Gene Expression of Osteoblastic Cells on Biomimetic Apatite Surface | ||
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K. TAKEUCHI1, Y.F. CHOU2, I. NISHIMURA1, B.M. WU3, and T. OGAWA1, 1 The Jane and Jerry Weintraub Center of Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA, USA, 2 Department of Bioengineering, UCLA School of Engineering and Applied Science, Los Angeles, CA, USA, 3 Department of Material Science and Engineering, UCLA School of Engineering and Applied Science, Los Angeles, CA, USA Biomimetic apatite is known to stimulate osteoblastic maturation in vitro and promote bone formation in vivo. However, cellular proliferation and differentiation control resulting in this altered osteogenic response is unknown. Previously we reported a rapid precipitation method for apatite coating on various biomaterials (J Dent Res 81SI: #2134). Objective: The goal of this study was to characterize behavior and phenotype of bone marrow derived osteoblastic cells on the newly developed apatite. Methods: To produce apatite coated dishes, polystyrene culture dishes were plasma etched and immersed in 5x SBF for 24 hr, then immersed in Mg-free 5x SBF for 48 hr. Polystyrene culture dishes with plasma etching alone were prepared as control. Primary osteoblastic cells were derived from rat femur bone marrow and cultured in a-MEM with 15% FBS, 10-8 M dexamethasone, 10 mM b-glycerophosphate, 50 µg/ml ascorbic acid. The osteoblastic cells were seeded at 2 x 104/cm2 density onto the apatite coated and control dishes. Alkaline phosphatase (ALP) activity was detected by a dual staining method with Naphthol AS-MX-Phosphate and Fast Red TR at day 3 after seeding. The number of vital cells was assessed using fluorescent microscopy after CalceinAM staining at day 1, 3 and 7. The mRNA samples extracted from the cells at day 3, 7 and 14 were subjected to RT-PCR. Results: All of the cells on the apatite exhibited positive ALP at day 3, while 63.9% of the cells were positive on the control. The total number of cells was consistently greater on the control than on the apatite at day 3 and 7 (p<0.001, two-way ANOVA). Gene expressions of osteocalcin and osteopontin were up-regulated on the apatite compared to the control, while type-I collagen expression remained same. Conclusion: The newly developed apatite may inhibit proliferation, but accelerate differentiation of rat bone marrow derived osteoblastic cells. | ||
| Seq #216 - Cellular Response 3:45 PM-5:00 PM, Friday, 27 June 2003 Svenska Massan Exhibition Hall B | ||
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