Singaravelu Janani, Zhao Lian, Fariss Robert N, Nork T Michael, Wong Wai T
Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Building 6, Room 215, Bethesda, MD, 20892, USA.
Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
Brain Struct Funct. 2017 Aug;222(6):2759-2771. doi: 10.1007/s00429-017-1370-x. Epub 2017 Feb 17.
Microglia, the principal resident immune cell in the retina, play constitutive roles in immune surveillance and synapse maintenance, and are also associated with retinal disease, including those occurring in the macula. Perspectives on retinal microglia function have derived largely from rodent models and how these relate to the macula-bearing primate retina is unclear. In this study, we examined microglial distribution and cellular morphology in the adult rhesus macaque retina, and performed comparative characterizations in three retinal locations along the center-to-periphery axis (parafoveal, macular, and the peripheral retina). We found that microglia density peaked in the parafoveal retina and decreased in the peripheral retina. Individual microglial morphology reflected macular specialization, with macular microglia demonstrating the largest and most complex dendritic arbors relative to other retinal locations. Comparing retinal microglia between young and middle-aged animals, microglial density increased in the macular, but not in the peripheral retina with age, while microglial morphology across all locations remained relatively unchanged. Our findings indicate that microglial distribution and morphology demonstrate regional specialization in the retina, correlating with gradients of other retinal cell types. As microglia are innate immune cells implicated in age-related macular diseases, age-related microglial changes may be related to the increased vulnerability of the aged macula to immune-related neurodegeneration.
小胶质细胞是视网膜中主要的常驻免疫细胞，在免疫监视和突触维持中发挥着组成性作用，并且还与包括黄斑疾病在内的视网膜疾病相关。关于视网膜小胶质细胞功能的观点很大程度上来自啮齿动物模型，而这些模型与有黄斑的灵长类动物视网膜之间的关系尚不清楚。在本研究中，我们检查了成年恒河猴视网膜中小胶质细胞的分布和细胞形态，并在沿中心到周边轴的三个视网膜位置（旁中央凹、黄斑和周边视网膜）进行了比较特征分析。我们发现小胶质细胞密度在旁中央凹视网膜中达到峰值，并在周边视网膜中降低。单个小胶质细胞的形态反映了黄斑的特殊性，与其他视网膜位置相比，黄斑小胶质细胞具有最大且最复杂的树突分支。比较年轻和中年动物的视网膜小胶质细胞，随着年龄增长，黄斑中的小胶质细胞密度增加，而周边视网膜中的小胶质细胞密度没有增加，而所有位置的小胶质细胞形态相对保持不变。我们的研究结果表明，小胶质细胞的分布和形态在视网膜中表现出区域特殊性，与其他视网膜细胞类型的梯度相关。由于小胶质细胞是与年龄相关性黄斑疾病相关的固有免疫细胞，与年龄相关的小胶质细胞变化可能与老年黄斑对免疫相关神经退行性变的易感性增加有关。
