关于BMP4 is required in the mouse cochlea development

张小盒 · 发表于 2014-12-2 19:52

[Abstract] Objective: To determine the role of BMP4 signal in developing auditory epithelium. Methods: Developing auditory epithelia with mesenchyme were first dissected and established in vitro as intact cochlear epithelia，which were cultured with BMP4 or the BMP-inhibitor Noggin from embryonic day 11.5 (E11.5) to E13.5. Then, Explants were maintained by serum-free cultured medium until the epithelia reached a developmental stage equivalent to E18.5 in vivo (referred to as E11.5 +7d in vitro (DIV), E12.5 +6 DIV and E13.5 +5 DIV). Finally, explants were fixed and labeled with the combination of Phalloidin and Myosin7a or of Sox2 and Myosin7a to determine the number of hair cells and support cells within this region. In the whole process, explants were cultured with BMP4 or Noggin in different concentrations. The final concentrations of BMP4 were 10.0 or 20.0 ng/mL respectively, and of Noggin were 0.1 or 0.3μg/mL respectively. Furthermore, noggin were together with BMP4 to determine whether BMP4 could reverse the effect of noggin on implants. The final concentration of BMP4 was 75.0 ng/ ml and of Noggin was 0.3μg/ ml respectively. Results: Hair cells were increased from E11.5 to E13.5 cultured with BMP4, and dramatic increasing was on E 12.5. The number of hair cells was 694.16±104.81 in E12.5+6 DIV with BMP4 20 ng/mL, 476.94±100.81 in E12.5+6 DIV without BMP4 . However, when cultured with Noggin, hair cells are decreased from E11.5 to E13.5, but the most dramatic reduction was at E12.5(61.11±22.29). Conclusions: BMP4, to some degree, could promote hair cells differentiation and growth, while Noggin caused a significantly reduction of sensory domain and number of both hair cells and support cells, but the effect of BMP4 or Noggin was different at various development stages of auditory epithelium.