小鼠视网膜片层化及神经干细胞的增殖与分化

Lamination of the mouse retina and the neural stem cell proliferation and differentiation

目的通过观察小鼠视网膜神经干细胞增殖与双极细胞分化过程,研究视网膜的发生及片层化。方法应用免疫荧光、5’-溴脱氧尿嘧啶核苷(BrdU)检测技术和HE染色法对胚胎及出生后小鼠视网膜形态结构及神经干细胞的增殖、分化进行观察,对视网膜BrdU和蛋白激酶Cα(PKC-α)阳性细胞密度进行统计。结果 1.小鼠视网膜在胚胎时期分化出色素上皮层、神经母细胞层和神经节细胞层。出生后,神经母细胞层逐渐分化出各个层,至小鼠睁眼时基本分化完全。2.小鼠视网膜干细胞在胚胎期大量增殖,出生后增殖放慢并逐渐分化为各类细胞。经统计分析发现,视网膜干细胞在胚胎时期数量逐渐增多,到出生当天数量达到最大值,出生后,神经干细胞开始分化,数量逐渐减少。3.小鼠视网膜双极细胞从出生后第5天(P5)开始发育,至P20时发育完全。结论小鼠视网膜的片层化与其功能的成熟相一致,视网膜的神经干细胞在出生后前期为分化高峰期,逐渐分化为不同类型的细胞。P10以后仅在睫状体处存在神经干细胞,可能与成年以后的修复功能相关。

Objective To investigate the retina neural stem cell proliferation and the differentiatiation of bipolar cells, the histogenesis and lamination of mouse retina. Methods The immunofluorescent labeling, BrdU detection and HE staining were carried out in the study. BrdU and PKC-a positive cells from embryonic and postnatal retina were measured, and the regression analyses and statistical tests were performed. Results 1. In the early embryonic days, the pigment epithelium, neuroblastoma layer were visualized. After birth, neuroblastoma layer gradually developed into different layers of retina, and the fully developed retina was observed at the age of eye opening. 2. The stem cells in the retina proliferated and differentiated into various types of cells during the embryonic days, and the proliferation slowed down after birth. With statistical analysis, we found that the number of retinal stem cells gradually increased during the embryonic period and reached the peak at PO. After birth, the neural stem cell started to differentiate, therefore their number reduced gradually. 3. Mouse retinal bipolar cells appeared at P5, and they did not mature until P20. Conclusion The neuroblastoma layer plays an important role in the lamination of retina, and the maturity of retinal morphology is consistent with its functions. The neural stem cell proliferation and differentiation reach their peaks at the neonate day, and the stem cells gradually differentiate into different cell types. In the adult, there are neural stem cells only in the ciliary body, suggesting their repair function after birth.