Expression Of Pigment Formation Related Protein In Rat Retina During Embryo Development

Objetive:Microphthalmia transcription factor(MITF),Tyosinase(Tyr), tyrosinase related protein-1(TRP1), retinal pigment epitheliu protein-65 (RPE65) induce and control the formation of pigment particles, an organelle in RPE which contributes to the etiology of such eye diseases as pigmentation glaucoma, autoimmunol diseases and retinal degeneration. So this study was designed to observe the expression of these pigment formation related proteins during embryonic development of BN rats, which may provide information on regeneration or replace of RPE cells.Methods:It was an randomized, control, experimental research. Expression of pigment formation related protein including MITF, Tyosinase, TRP1, RPE65 during retinal development of BN rats by immunohistochemistry at E7 ( Embryonic dagy 7), E14, P0 (equivalent to to E21) , W10 (10 weeks after the birth) under microscope or fluorescein microscop.Results:Morphological observation of retinal development in BN rat. Monolayer of Pigment epithelium and 16～18 layers of neural cells (neuroblast layer) were seen on E14. Pigment epithelium layer, outer neural layers, chievitz layer, inner neural layer was observed respectively on P0. Inner plexiform layer formed and some cells began to differentiate into gangliocytes. In week 10 after the birth, retinal developed completely.Immunohistochemistry analysis of expression of pigment formation related gene in retinal development of embryonic BN rats.No exprssion of MITF, Tyrosinase, TRP1, RPE65 was detected on E7.On E14, prominent brown-yellow particles were observed in the cytoplasm and nuclei of inner neural layer and retinal pigment epithelium when analyzed with primary antibodies to MITF,Tyrosinase,TRP1,indicating positive expression of these proteins , while no expression of RPE65 present in E14 retina.Expression of MITF, Tyrosinase,TRP1 persisted till birth (P0) in the similar way to E14, but more prominent expression of MITF occurred in the cytoplasm and nuclei of RPE than E14. RPE65 began to express only in the cytoplasm and nuclei of RPE.In week 10 after birth, silencing expression of MITF was discoverded, expression of Tyrosinase, or TRP1 in inner neural layer , or expression of RPE65 in RPE cells dicreased compared with E14 and P0 group.Conclusions:1 Retinal development occurred in the second embryonic week, but is not mature until birth.2 MITF positive cells appeared in RPE and inner neural layer in middle or late embryo (E14～P0), increased on P0, disappeaed in W10.3 Expresssion Tyr, TRP1 was detected in middle or late embryonic rat retina, lasted till the birth, and went down in week 10 after birth.4 Prominent expression of RPE65 was found in late embryonic stage, persisted but went down till 10 weeks after the birth.