成对框基因2蛋白在C57BL/6J小鼠脑发育进程中的表达

Expression of paired box gene 2 protein in the developing brain of C57BL/6J mice

目的 研究正常C57BL/6J小鼠脑发育进程中的组织形态学变化以及成对框基因2(Pax2)蛋白在胚胎期和出生后脑组织中的表达规律。方法 取C57BL/6J小鼠胚胎期11.5 d、13.5 d、15.5 d的胎鼠头部和胚胎期17.5 d、出生后0 d、7 d、14 d和30 d小鼠的全脑组织进行石蜡包埋,连续矢状位切片后进行HE染色和免疫组织化学染色。结果 胚胎期11.5d可见小鼠完整的5个脑泡结构,15.5 d大脑皮质出现5层结构,小脑皮质外颗粒层明显可见。出生后各脑区按照时空顺序继续发育,到P30大脑皮质和小脑皮质均发育成熟出现典型的结构特征。Pax2蛋白在脑组织中的表达主要定位于细胞核和神经纤维上,在胚胎期的表达主要集中在脑桥延髓部位且呈弥漫性表达,E13.5达到高峰,出生后在脑桥延髓的表达逐渐减弱,但在小脑中的表达较胚胎期增强;E13.5时在小脑内开始少量表达,P7时达到高峰,P14后表达量逐渐降低;Pax2蛋白在外颗粒层中于E17.5时开始表达,出生后主要在内颗粒层和髓质中强烈表达,到P30时表达减弱,仅分布在内颗粒层中。结论 小鼠脑发育在一定的时空顺序下,经历了一个复杂的过程。Pax2蛋白在小鼠脑组织中的表达呈现出一定的时空变化规律,可能参与小鼠脑桥延髓早期区域化的建立和小脑的发育过程。

Objective To study the histomorphological changes in the developing brain of normal C57BL/6J mice and the expression pattern of paired box gene 2(Pax2) protein in the embryonic and postnatal brain tissues. Methods Paraffin-embedded brain tissues from mice at different developmental stages were sagittal and serially sectioned for immunohistochemical staining and HE staining. Results At 11.5 d of embryonic life(E11.5), five intact cerebral vesicle structures were visible. At E15.5, five layers of cerebral cortex appeared, and the external granular layer of the cerebellum was clearly visible. After birth, the brain regions continued to develop in a spatial and temporal sequence, and by P30 both the cerebral cortex and cerebellar cortex had matured and developed typical structural features. The expression of Pax2 protein in brain tissue was mainly localized in the nucleus and nerve fibers, and the expression of Pax2 protein in the embryonic stage was mainly concentrated in the pontine medulla and was diffusely expressed, with a peak at E13.5. After birth, the expression in the pontine medulla gradually decreased, but the expression in the cerebellum was enhanced compared with the embryonic stage. At E13.5, the expression of Pax2 protein in the cerebellum started to be small and peaked at P7, while the expression of P14 and P30 decreased gradually. At E17.5, Pax2 protein expression appeared in the external granular layer and was strongly expressed mainly in the inner granular layer and medulla after birth, and by P30, Pax2 protein expression diminished and was distributed only in the inner granular layer. Conclusion Mouse brain development undergoes a complex process in a certain spatial and temporal order. The expression of Pax2 protein in mouse brain tissue showed a certain spatial and temporal change pattern,which may be involved in the establishment of early regionalization of the pontine medulla and the development of the cerebellum in mice.