École d'Optométrie, Université de Montréal, Montreal, QC H3T 1P1, Canada.
Department of Psychiatry, McGill University, Montreal, QC H3A 1A1, Canada.
Cells. 2022 Sep 3;11(17):2751. doi: 10.3390/cells11172751.
Among the deficits in visual processing that accompany healthy aging, the earliest originate in the retina. Moreover, sex-related differences in retinal function have been increasingly recognized. To better understand the dynamics of the retinal aging trajectory, we used the light-adapted flicker electroretinogram (ERG) to functionally assess the state of the neuroretina in a large cohort of age- and sex-matched vervet monkeys ( = 35), aged 9 to 28 years old, with no signs of obvious ocular pathology. We primarily isolated the cone-bipolar axis by stimulating the retina with a standard intensity light flash (2.57 cd/s/m) at eight different frequencies, ranging from 5 to 40 Hz. Sex-specific changes in the voltage and temporal characteristics of the flicker waveform were found in older individuals (21-28 years-old, = 16), when compared to younger monkeys (9-20 years-old, = 19), across all stimulus frequencies tested. Specifically, significantly prolonged implicit times were observed in older monkeys ( < 0.05), but a significant reduction of the amplitude of the response was only found in old male monkeys ( < 0.05). These changes might reflect ongoing degenerative processes targeting the retinal circuitry and the cone subsystem in particular. Altogether, our findings corroborate the existing literature in humans and other species, where aging detrimentally affects photopic retinal responses, and draw attention to the potential contribution of different hormonal environments.
在伴随健康衰老的视觉处理缺陷中，最早起源于视网膜。此外，人们越来越认识到视网膜功能的性别差异。为了更好地了解视网膜衰老轨迹的动态，我们使用光适应闪烁视网膜电图（ERG）在一个由年龄和性别匹配的恒河猴组成的大队列中（= 35），功能评估神经视网膜的状态，这些猴子年龄在 9 至 28 岁之间，没有明显眼部病理的迹象。我们主要通过用标准强度的光闪光（2.57 cd/s/m）以八个不同的频率刺激视网膜（5 至 40 Hz），来分离出视锥-双极轴。在所有测试的刺激频率下，与年轻的猴子（9-20 岁，= 19）相比，老年个体（21-28 岁，= 16）的闪烁波形的电压和时间特征存在性别特异性变化。具体来说，在老年猴子中观察到明显延长的潜伏期（<0.05），但只有老年雄性猴子的反应幅度明显降低（<0.05）。这些变化可能反映了针对视网膜电路，特别是视锥系统的进行性退化过程。总的来说，我们的发现与人类和其他物种的现有文献一致，在这些文献中，衰老对明适应视网膜反应有不利影响，并引起了对不同激素环境潜在贡献的关注。
