Rex Tonia S, Lewis Geoffrey P, Geller Scott F, Fisher Steven K
Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA.
Mol Vis. 2002 Apr 16;8:114-8.
To identify changes in S- and M-sensitive cone opsin gene expression following retinal detachment (RD) and reattachment.
Cat retinas were detached for 1, 3, 7, or 28 days, or reattached after 1 h, 1 day, or 3 days of RD and fixed in 4% paraformaldehyde. Pieces of mid-peripheral retina were removed from the same region of each detached, normal (attached), and reattached retina and embedded in paraffin. Paraffin sections (8 mm) were processed for in situ hybridization using S- or M-cone opsins, rod opsin, or phosducin riboprobes in vitro transcribed from cat partial cDNAs. Labeled cells were counted to obtain the number of labeled cells/mm retina.
The number of cells labeled with the anti-sense cone opsin riboprobes, and the intensity of this label, decreased after RD. The number of cones labeled with the anti-sense S-opsin riboprobe decreased to 42% of normal at 3 days of RD. The number of M-opsin mRNA-positive cones decreased to 4% of normal at 3 days of RD. The number of cells positive for M-opsin or S-opsin mRNA recovered to near normal levels after reattachment. Phosducin and rod opsin mRNA labeling was near normal in surviving rod photoreceptors after RD.
Cones and rods behave differently after detachment. There are significant obstacles to overcome in order to study the responses of cones after RD because surviving cells no longer label with antibodies used as cone markers in normal retina. The results of this study show that: (1) After RD, surviving cones decrease their expression of opsin mRNA while rods do not; (2) Upon reattachment of the retina, the cones once again begin to express their opsins; (3) Most cones survive short-term detachments; and (4) Defects in cone-based vision after reattachment may not be based mainly on the loss of cones but due to other changes in these cells, for example, reduced phototransduction and/or changes in synaptic connectivity to second order neurons.
确定视网膜脱离（RD）及复位后S-和M-敏感视锥视蛋白基因表达的变化。
将猫的视网膜脱离1、3、7或28天，或在视网膜脱离1小时、1天或3天后复位，然后用4%多聚甲醛固定。从每个脱离、正常（附着）和复位视网膜的相同区域取出中周部视网膜组织块，石蜡包埋。石蜡切片（8μm）用体外转录自猫部分cDNA的S-或M-视锥视蛋白、视杆视蛋白或转导素核糖探针进行原位杂交。计数标记细胞以获得每毫米视网膜的标记细胞数。
视网膜脱离后，用反义视锥视蛋白核糖探针标记的细胞数量及其标记强度降低。用反义S-视锥视蛋白核糖探针标记的视锥细胞数量在视网膜脱离3天时降至正常的42%。M-视锥视蛋白mRNA阳性视锥细胞数量在视网膜脱离3天时降至正常的4%。视网膜复位后，M-视锥视蛋白或S-视锥视蛋白mRNA阳性细胞数量恢复到接近正常水平。视网膜脱离后，存活的视杆光感受器中转导素和视杆视蛋白mRNA标记接近正常。
视网膜脱离后视锥和视杆的表现不同。由于存活细胞不再能用正常视网膜中用作视锥标记的抗体进行标记，因此研究视网膜脱离后视锥的反应存在重大障碍。本研究结果表明：（1）视网膜脱离后，存活的视锥细胞视蛋白mRNA表达降低，而视杆细胞则不然；（2）视网膜复位后，视锥细胞再次开始表达其视蛋白；（3）大多数视锥细胞能在短期脱离中存活；（4）视网膜复位后基于视锥的视觉缺陷可能主要不是由于视锥细胞的丢失，而是由于这些细胞的其他变化，例如光转导减少和/或与二级神经元的突触连接改变。
