垂体同源盒家族因子3基因在大鼠脊髓发育和生存维持过程中的表达变化

The altered expression of Pitx3 gene in the developing and survival spinal cord of rats

目的:探讨垂体同源盒家族因子3(Pitx3)基因在SD大鼠脊髓不同年龄阶段的表达变化以及细胞定位。方法:采用半定量RT-PCR和Western Blot检测不同年龄组大鼠脊髓中Pitx3 mRNA及蛋白水平表达变化;采用免疫荧光和免疫组化染色显示Pitx3在脊髓中的细胞定位。结果:(1)RT-PCR和Western Blot检测显示Pitx3基因在各年龄组脊髓各段均有表达;大鼠脊髓发育过程中Pitx3 mRNA及其蛋白水平出生前逐渐升高,在出生后(P0 d)达高锋,以后维持在一定的生理水平,且出生以后随年龄的增长表达呈下调趋势;(2)免疫荧光双标证实Pitx3蛋白在P0 d大鼠脊髓主要定位于脊髓灰质,与神经元的标记物NeuN存在共定位;免疫组化检测显示Pitx3蛋白集中分布于各年龄组脊髓灰质腹角运动神经元胞质中,少量分布于背角和侧角神经元胞质中。结论:在大鼠脊髓发育和生存维持过程中,Pitx3在基因和蛋白水平呈现明显的时相变化;提示Pitx3基因的表达在脊髓腹角运动神经元的发育和生存维持中可能发挥一定的调控作用。

Objective： To explore the changed expression and localization of paired-like homeodomain transcription factor 3（Pitx3） gene in the developing and survival spinal cord of Sprague-Dawley（SD） rats at different ages.Methods： Semiquantitative RT-PCR and Western Blot were used to detect the changed expression of mRNA and protein levels of Pitx3 in the spinal cord of rats in different age groups,respectively.Immunofluorescence and immunohistochemical staining were used to observe the cellular distribution of Pitx3 in the spinal cord.Results：（1） The expressions of Pitx3 were detected in all spinal segments at different ages by using semiquantitative RT-PCR and Western Blot.During the development of the spinal cord,the expressions of mRNA and protein of Pitx3 began to increase at prenatal period,peaked at postnatal 0 day,maintained at some physiological levels at postnatal period.Decreasing expression of the Pitx3 was found with the age increasing at postnatal period;（2） Immunofluorescence staining showed that Pitx3 mainly distributed in the spinal gray matter during the postnatal 0 day,where it co-localized with the marker of neuron,NeuN.Immunohistochemical staining showed that Pitx3 extensively distributed in the ventral horn of spinal cord in different age groups,slightly distributed in the neuroplasm of dorsal horn and lateral horn.Conclusion： The protein and mRNA expressions of Pitx3 appear a changeable character during spinal cord development and survival.It is presumed that the expression of Pitx3 probably has a role of regulating the development and survival of ventral horn motor neuron in the spinal cord.