[Bone morphogenetic protein-4 regulates embryonic tongue morphogenesis].

Objective: To analyze the effect of Bone morphogenesis 4 and its antagonist Noggin on morphogenesis of tongue.

Methods: Dissected rats to get embryonic day 13 (E13) tongues; fed E13 tongues in standard medium, BMP4 (0.03 mg/L, 0.3 mg/L, 1 mg/L), and the antgonist Noggin(1 mg/L, 3 mg/L, 10 mg/L) medium; cultured for 3 days; fixed samples, observed tongues with scanning electronic microscope (SEM); measured the whole tongue length, anterior 1/8, 1/4 width and middle width of cultured tongues and analyzed data with SPSS 10.0. To further study the effects of BMP4 on epithelial and mesenchymal cell proliferation, Affi-gel blue gel beads were applied. Beads were soaked in PBS and BMP4 (667 mg/L), and implanted in the E13 embryonic tongues; then after cultured in standard medium for 3 days, tongues were embedded in O.C.T. and cut into 12 microm series sections. Ki67 was detected by immunohistochemical method.

Results: (1)Whole length of tongues changed greatly (P<0.05), the length was shortened in BMP4 groups (0.03 mg/L group 877.3+/-67.6 microm, 0.3 mg/L group 838.5+/-88.9 microm, 1 mg/L group 718.7+/-38.6 microm) compared with standard medium (1 037.8+/-126.2 microm), Noggin groups had no obvious change; the anterior 1/8 width of tongues changed significantly(P<0.05), the anterior 1/8 width was narrower in BMP4 groups (0.03 mg/L group 332.1+/-80.9 microm, 0.3 mg/L group 305.1+/-51.3 microm, 1 mg/L group 276.9+/-45.9 microm) compared with standard group(639.1+/-106.2 microm), except 10 mg/L group, Noggin groups were wider (1 mg/L group 815.5+/-90.3 microm, 3 mg/L group 857.6+/-87.1 microm, 10 mg/L group 807.1+/-113.8 microm); the anterior 1/4 width of tongue changed magnificently, also(P<0.05), BMP4 groups were narrower (0.03 mg/L group 421.3+/-43.8 microm, 0.3 mg/L group 407.3+/-15.6 microm, 1 mg/L group 363.7+/-24.7 microm) compared with standard group (653.7+/-101.6 microm), whereas, Noggin groups were wider greatly (1 mg/L group 838.0+/-130.5 microm, 3 mg/L group 947.2+/-34.9 microm, 10 mg/L group 889.4+/-74.6 microm); the middle width of tongue changed significantly(P<0.05), width of BMP4 groups were narrower (0.03 mg/L group 567.3+/-35.8 microm, 0.3 mg/L group 548.4+/-30.5 microm, 1 mg/L group 457.4+/-48.0 microm) compared with standard medium (683.1+/-79.8 microm), and Noggin groups had widening tendency, difference in 3 mg/L group is magnificent (1 mg/L group 776.2+/-134.1 microm, 3 mg/L group 964.3+/-44.3 microm, 10 mg/L group 777.2+/-46.7 microm). (2) The expression of Ki67 in both epithelium and mesenchym adjacent to BMP4 beads reduced greatly.

Conclusion: BMP4 could effect morphological development of embryonic tongue, which could change spatula-shape tongue into short, narrow and tip-point one, the antagonist Noggin tongue was wider and longer; BMP4 inhibit cell proliferation in embryonic tongues.