Ngn2和Math6在小鼠内耳不同时期表达的初步研究

目的研究neurogenin2(ngn2)和math6在不同时期小鼠内耳的表达变化,并初步探讨其对螺旋神经元发育的调控作用。方法本实验选取不同时期健康的BALB/c小鼠,以E12.5、E13.5、E14.5、E17.5、P1、P7和成年为观察时间点,应用real-time PCR、免疫组织化学方法检测ngn2、math6在耳蜗中mRNA和蛋白的表达。结果 (1)re al-time PCR结果提示ngn2在E12.5d呈高表达,随后在E13.5d表达量下调,直至成年呈低水平表达;math6在E12.5-P1都呈较高水平表达,其中在P1达到高峰,随后于P7至成年表达量下调。(2)免疫组织化学结果提示,在E13.5、E14.5和P1,ngn2和math6在螺旋神经节处(或螺旋神经元细胞核处)有不同程度的阳性表达;在成年期,math6在细胞核有弱表达,但ngn2几乎不表达,各组间差异有统计学意义(P<0.05)。结论 (1)ngn2在E12.5d表达呈高峰,提示其在有增殖能力的神经祖细胞中起作用;math6在E12.5d-P1呈高表达,提示其在神经祖细胞的增殖以及分化中其起重要作用;(2)ngn2和math6在耳蜗中表达的空间和时间模式的重叠和差异,提示它们在调控通路中可能受到共同的分子调控。

Expression of neurogenin2 and math6 in the embryonal and postnatal mouse inner ear and their molecular regulation

Objective To reveal the distribution and time sequence patterns of neuroegenin2 and math6 expression in the embryonic, postnatal and adult mouse spiral ganglions, and to study the regulation of the developing spiral ganglion. Methods An immunohistochemistry method was used to detect expression of ngn2 and math6 in the cochlear tissue of E12.5, E13.5, E14.5, E17.5, P1, P7 and adult mice. Levels of ngn2 and math6 mRNA expression were examined using real-time PCR. Results The expression level of ngn2 mRNA reached a peak at E12.5 , followed by a gradual decrease from E13.5 to adult age. In addition, the expression level of math6 mRNA showed an increase at E12.5 and P1, followed by a decrease until adult age. The results of immunohistochemistry showed that ngn2 and math6 were expressed in the spiral ganglion (or the nucleus of spiral ganglion cells) at E13.5, E14.5 and P1 ; and that the protein of math6 was less expressed in adult than the embryonic spiral ganglion. The differences in ngn2 and math6 protein expression at various time points were statistically significant (P<0.05). Conclusion The highest expression of ngn2 in spiral ganglion is at E12.5, suggesting its very import role in neural progenitors proliferation. High expression of math6 seems to occur from E12.5 to P1, indicating that math6 may be related to regulation of dividing neural progenitors and their differentiation into postmitotic neurons. The overlaps and differences in spatial and temporal distribution patterns of ngn2 and math6 expression suggest a common signaling pathway in their molecular regulation