■光感受器间类视黄醇结合蛋白(IRBP)在眼睛生长中的作用及其在细胞稳态中的作用仍然知之甚少。一种假设提出IRBP基因的早期条件性缺失可能导致视网膜变性的近视反应,而晚期条件性缺失(在确定眼睛大小后)可能导致视网膜变性而没有近视。这里,我们试图了解在没有IRBP的情况下,后续视网膜变性是否需要既往近视.这项研究调查了在近视或视网膜变性中,任何细胞类型或发育阶段是否更重要。
■IBRPfl/fl小鼠用5个Cre驱动系:HRGP-Cre,Chx10-Cre,Rho-iCre75、HRGP-CreRho-iCre75和Rx-Cre。通过数字液滴PCR(ddPCR)分析小鼠的IRBP基因表达。使用谱域光学相干断层扫描(SD-OCT)和苏木精和曙红(H&E)染色测试年轻成年(P30)小鼠的视网膜变性和形态。使用视网膜电图(ERGs)分析功能。通过外眼测量和全眼生物测定来比较眼睛大小和眼轴长度。
■在所有结果测量中,当繁殖到IRBPfl/fl时,HRGP-Cre和Chx10-Cre系与单独的IRBPfl/fl没有差异。有了Rho-iCre75系列,SD-OCT成像和死后H&E染色观察到视网膜厚度小但显著减少,而眼轴长度无增加.HRGP-CreRho-iCre75和Rx-Cre系均显示视网膜厚度和外核层细胞计数显着降低。使用外部眼睛测量和SD-OCT成像,两条线都显示眼睛大小增加。最后,在苏格兰,这两条线的功能大致减半,明视,和闪烁的ERG。
■我们的研究支持以下假设:对于眼睛大小测定和视网膜稳态,当IRBP必须以杆或锥表达以预防近视(P7-P12)和变性(P21及以后)时,有两个关键的时间窗口.视杆特异性IRBP敲除(Rho-iCre75)显示出明显的视网膜功能丧失,而没有近视,表明这两种表型是独立的。IRBP是需要早期发展的光感受器和眼睛大小,而Rho-iCre75IRBPfl/fl敲除导致无近视的视网膜变性。
UNASSIGNED: Interphotoreceptor retinoid-binding protein\'s (IRBP) role in eye growth and its involvement in cell homeostasis remain poorly understood. One hypothesis proposes early conditional deletion of the IRBP gene could lead to a myopic response with retinal degeneration, whereas late conditional deletion (after eye size is determined) could cause retinal degeneration without myopia. Here, we sought to understand if prior myopia was required for subsequent retinal degeneration in the absence of IRBP. This study investigates if any cell type or developmental stage is more important in myopia or retinal degeneration.
UNASSIGNED: IBRPfl/fl mice were bred with 5 Cre-driver lines: HRGP-Cre, Chx10-Cre, Rho-iCre75, HRGP-Cre Rho-iCre75, and Rx-Cre. Mice were analyzed for IRBP gene expression through digital droplet PCR (ddPCR). Young adult (P30) mice were tested for retinal degeneration and morphology using spectral-domain optical coherence tomography (SD-OCT) and hematoxylin and eosin (H&E) staining. Function was analyzed using electroretinograms (ERGs). Eye sizes and axial lengths were compared through external eye measurements and whole eye biometry.
UNASSIGNED: Across all outcome measures, when bred to IRBPfl/fl, HRGP-Cre and Chx10-Cre lines showed no differences from IRBPfl/fl alone. With the Rho-iCre75 line, small but significant reductions were seen in retinal thickness with SD-OCT imaging and postmortem H&E staining without increased axial length. Both the HRGP-Cre+Rho-iCre75 and the Rx-Cre lines showed significant decreases in retinal thickness and outer nuclear layer cell counts. Using external eye measurements and SD-OCT imaging, both lines showed an increase in eye size. Finally, function in both lines was roughly halved across scotopic, photopic, and flicker ERGs.
UNASSIGNED: Our studies support hypotheses that for both eye size determination and retinal homeostasis, there are two critical timing windows when IRBP must be expressed in rods or cones to prevent myopia (P7-P12) and degeneration (P21 and later). The rod-specific IRBP knockout (Rho-iCre75) showed significant retinal functional losses without myopia, indicating that the two phenotypes are independent. IRBP is needed for early development of photoreceptors and eye size, whereas Rho-iCre75 IRBPfl/fl knockout results in retinal degeneration without myopia.