Bone growth is stimulated by BMP4 and FGF in an in vitro bone model

Abstract

Abstract Introduction: Analysis of extrinsic stimuli on osteoblast biology is limited to isolated cell cultures where cell-cell interactions cannot be adequately explored. In vivo experiments circumvent these short-comings but are expensive and difficult to isolate. Our objective was to develop a useful in vitro bone culture model to enable more complex analysis of osteoblast biology. Methods: After Fisher rat (n = 19) sacrifice on neonatal day 1, tibias were microdissected from surrounding structures and cultured on tissue culture inserts. Serum free media supplementation determined tibia groups (n = 12 each): Group 1 without supplementation, Group 2 with rh-FGF-2, and Group 3 with rh-BMP4. On days 2 and 5, half the bones from each group were weighed and prepared for analysis. Results: Histological analysis showed intact cortical and cancellous bone architecture. Further, proximal and distal epiphysis remained intact. All groups experienced initial weight decreases by day 2, but stimulated bones increased in weight by day 5. When non-stimulated versus stimulated mean weight changes were compared, Group 3 showed the greatest increases by day 5 (p Conclusions: We have demonstrated that the neonatal rat tibia is an excellent long bone organ culture model capable of sustained growth in vitro. Further, these cultures retain the ability to respond to known bone growth factors. This model is useful for analyzing complex epigenetic manipulations in culture.