大鼠视网膜胚胎发育的形态学改变及低氧诱导因子-1α的表达

The morphous difference and expression of HIF-1α in rat retina during embryonic development

目的观察大鼠视网膜胚胎发育的形态学改变及低氧诱导因子-1α（HIF-1α）的时空表达,探讨HIF-1α在视网膜胚胎发育过程中的作用。方法对胚胎10-20d大鼠视网膜进行光镜观察;用免疫组织化学方法检测不同胎龄视网膜（10、12、14、16、18、20d）HIF-1α的表达。结果大鼠视网膜发育起自胚胎10d;14d外层色素上皮细胞呈单层排列,神经上皮层逐渐增厚;16d神经上皮层分为内外两层;18d出现chievitz层;20d内网层形成,神经节细胞开始分化。至出生前,视网膜组织分为色素上皮细胞层、神经母细胞层和神经节细胞层。低氧诱导因子-1α在胚胎早期（10-12d）呈现高表达,随胎龄增加而表达减弱,且表达部位随发育进程而改变。结论大鼠视网膜发生起始于胚胎第10d,随胎龄增加逐渐分化,至出生前发育尚不完善。HIF-1α在大鼠胚胎期视网膜的时空表达变化提示HIF-1α可能参与了大鼠视网膜的胚胎发育过程。

Objective As a part of nervous system development retina embryonic development is closely related with steps of brain development.HIF-1α is a well-known signal for angiogenesis,but the recent report show that it exist widely in nervous developing embryonic tissues.This study was to investigate the morphous difference and expression of hypoxia inducible factor 1α（HIF-1α） during embryonic development of rat retina and explore the role of HIF-1α in retina development process.MethodsRat retina（8 eyes each group） from 10-to 20-day embryo（E10-E20） was examined by light microscope.Expression of HIF-1α protein in retinas of different-embryo-phase rats was detected by immunohistochemistry.ResultsThe formation of optical cup and layering of retina were recognized in the 10th day of embryo（E10） under the light miaroscope.In the 12nd day of embryo（E12）,the pigment epithelium cell was seen as a monolayer,and 6 to 8 layers of neural cells were seen and increased gradually to 16 to18 layers in the 14th day of embryo（E10）.In the 16th day of embryo（E16）,the neural epithelium differentiated into inner and outer neural layers and in the 18th day of embryo（E18）,and chievitz layer with light staining was found.In the 20th day of embryo（E20）,inner plexiform layer formed and some cells began to differentiate into gangliocytes.HIF-1α was positively expressed in cellular nuclear and cytoplasm of retinal pigment and retina in E10-E12 rats.In the E14 to E16 rats,HIF-1α was expressed in both inner and outer layers of retina with the strong expression in the ciliary marginal zone of peripheral retina and weak expression in the central part of retina.In late embryo stage,the expression of HIF-1α was mainly in retina ganglion cells.ConclusionThe retina of Wistar rat differentiate from the 10th day of embryo through the embryo phase but is still immature before birth.The varies of HIF-1α expression is depend upon rat embryo development,indicating that HIF-1α might participate the process of embryo development of rat retina.