View larger version (175K):
[in a new window]
|
Figure 1. In vitro development of re-associations between dental mesenchyme and dissociated epithelial cells from first lower molars at ED14. The re-associations were cultured for 12 hrs (A,F), 24 hrs (B,G), 2 days (C,H), 3 days (D,I,P,Q,R), 6 days (E,J), and 14 days (N,O,S,T). To visualize cell proliferation, we cultured ED14 first lower molars for 18 hrs in the presence of BrdU (K), and cultured re-associations for 54 hrs in vitro and 18 hrs in the presence of BrdU (P). Apoptosis was visualized after cells were stained for ssDNA on ED14 molars (L, arrow), and re-association was cultured for 3 days (Q, arrow). In situ hybridization for Shh was performed on first lower molars at ED14 (M), and re-associations were cultured for 3 days (R). After 14 days in culture, odontoblasts were functional and ameloblasts were polarized (N,O,S). Six cusps were observed, as can be seen on the histological horizontal section (O) or after 3D reconstruction of the mesenchyme (T). AM, ameloblast; BM, basement membrane; D, dentin; DE, dental epithelium; DM, dental mesenchyme; DP, dental papilla; IDE, inner dental epithelium; OD, odontoblast; ODE, outer dental epithelium; PEK, primary enamel knot; SEK, secondary enamel knot; SI, stratum intermedium; SR, stellate reticulum. Bar = 40 µm.
|
