Guérin C J, Lewis G P, Fisher S K, Anderson D H
Neuroscience Research Institute, University of California, Santa Barbara 93106.
Invest Ophthalmol Vis Sci. 1993 Jan;34(1):175-83.
Photoreceptor outer segments are in a dynamic state of membrane addition and disposal. This study was undertaken to determine how a standardized period of retinal detachment and varying periods of reattachment affect the renewal process.
To investigate the effects that retinal detachment and reattachment may have on this process, the neural retina from 12 adult rhesus monkeys (Macaca mulatta) was detached from the overlying retinal pigment epithelium (RPE) by subretinal injection of a balanced salt solution. After a standardized detachment period of 7 days, the two tissue layers were reapposed. Animals were labeled with 3H-fucose and killed at times ranging from 3-150 days after reattachment.
During the 7 day detachment period, the majority of rod outer segments (ROS) and cone outer segments (COS) degenerated, but inner segments remained intact. During the first week after reattachment, a rapid increase in rod and cone outer segment length occurred in the absence of disc shedding. This was accompanied by re-establishment of a modified morphologic relationship between the apical processes of the RPE and the regenerating outer segments. ROS and COS regained approximately 40% of their control lengths after a 2 wk reattachment period. By 30 days of reattachment, ROS had regained 72% of their normal length and COS had regained approximately 48%. After 150 days of reattachment, photoreceptor outer segment mean length was not statistically different from control areas. Autoradiographic results confirmed that new disc membranes were synthesized after reattachment. The rate of ROS membrane assembly was subnormal at reattachment time points up to 30 days.
Retinal detachment leads to a reduction in photoreceptor outer segment absolute length and membrane assembly rates. Increasing time of retinal reattachment is positively correlated with an increase in outer segment absolute length and a corresponding increase in membrane assembly rates. This recovery pattern in eyes without underlying pathology and after a relatively brief detachment interval may represent the upper limit of the recovery process.
光感受器外段处于膜添加和处置的动态状态。本研究旨在确定标准化的视网膜脱离期和不同的再附着期如何影响更新过程。
为了研究视网膜脱离和再附着可能对该过程产生的影响，通过视网膜下注射平衡盐溶液，将12只成年恒河猴（猕猴）的神经视网膜与上方的视网膜色素上皮（RPE）分离。在标准化的脱离期7天后，将两层组织重新贴合。用3H-岩藻糖标记动物，并在再附着后3至150天的不同时间处死。
在7天的脱离期内，大多数视杆外段（ROS）和视锥外段（COS）退化，但内段保持完整。在再附着后的第一周，在没有盘状小体脱落的情况下，视杆和视锥外段长度迅速增加。这伴随着RPE顶端突起与再生外段之间改变的形态学关系的重新建立。再附着2周后，ROS和COS恢复了其对照长度的约40%。到再附着30天时，ROS恢复了其正常长度的72%，COS恢复了约48%。再附着150天后，光感受器外段平均长度与对照区域无统计学差异。放射自显影结果证实再附着后合成了新的盘状膜。在再附着时间点直至30天时，ROS膜组装速率低于正常水平。
视网膜脱离导致光感受器外段绝对长度和膜组装速率降低。视网膜再附着时间的增加与外段绝对长度的增加以及相应的膜组装速率增加呈正相关。在没有潜在病理且脱离间隔相对较短的眼睛中，这种恢复模式可能代表了恢复过程的上限。
