Change Of Cell Proliferation Related Molecules Im Tgf-beta3 Null Mice

Tgf-b₃ null mice (Tgf-b₃ -/-) have cleft palate. Previous studies have shown a higher cell proliferation rate and less cell death in their palatal medial edge epithelium (MEE) (Martínez-Álvarez et al., 2000; Cui et al., 2003). In this work we aimed to know whether they show changes in the presence/distribution of some growth and transcription factors currently expressed in the embryonic palate and related with cell proliferation. Objectives: To compare the presence/distribution of EGF, FGF-10, PDGF-A, TGF-b₂, Msx-1, Bmp-2, Bmp-4, Shh and cell proliferation between Tgf-Β₃ -/- and +/+ embryonic palates. Material and methods: Embryonic day 14.5 (E14.5) C57/BL/6J Tgf-b₃ -/- and +/+ mouse heads were embedded in paraffin, sectioned and labelled with antibodies against EGF, FGF-10, PDGF-A and TGF-b₂ or embedded in gelatin and used to perform in situ hybridization in toto with Msx-1, Bmp-2, Bmp-4 and Shh riboprobes and sectioned. Tgf-b₃ +/- pregnant dams and their +/+ and -/- E14.5 embryos were treated following the instructions of the BrdU kit (Roche) to analyse cell proliferation. Proliferating cells were counted in both the MEE and underlying mesenchyme. Results: Compared with the +/+, there is less proliferation rate in the Tgf-b₃ -/- palatal mesenchyme, although this is not the case with the MEE. In the -/-, EGF and Msx-1 increase in the MEE and mesenchyme, respectively, Shh is absent in the MEE of the most anterior palatal region and the expression of Bmp2 decreases in the mesenchyme of the whole palate. The remaining molecules do not show any differences between the wild type and the mutant. Conclusion: There are changes in the proliferation rate and molecules related to cell proliferation in the embryonic palate of Tgf-b₃ null mice.

This work was granted by Comunidad de Madrid (GR/SAL/0539/2004), FIS (PI03/0185) and UCM/CM (2005) to the UCM group 920202.