Department of Anatomy, The University of Hong Kong, Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong, People's Republic of China.
PLoS One. 2012;7(8):e44036. doi: 10.1371/journal.pone.0044036. Epub 2012 Aug 31.
Retinal photoreceptors die during retinal synaptogenesis in a portion of retinal degeneration. Whether cone bipolar cells establish regular retinal mosaics and mature morphologies, and resist degeneration are not completely understood. To explore these issues, we backcrossed a transgenic mouse expressing enhanced green fluorescent protein (EGFP) in one subset of cone bipolar cells (type 7) into rd1 mice, a classic mouse model of retinal degeneration, to examine the development and survival of cone bipolar cells in a background of retinal degeneration. Our data revealed that both the development and degeneration of cone bipolar cells are independent of the normal activity of cone photoreceptors. We found that type 7 cone bipolar cells achieved a uniform tiling of the retinal surface and developed normal dendritic and axonal arbors without the influence of cone photoreceptor innervation. On the other hand, degeneration of type 7 cone bipolar cells, contrary to our belief of central-to-peripheral progression, was spatially uniform across the retina independent of the spatiotemporal pattern of cone degeneration. The results have important implications for the design of more effective therapies to restore vision in retinal degeneration.
在部分视网膜变性过程中，视网膜光感受器在视网膜突触发生过程中死亡。锥体双极细胞是否能建立规则的视网膜镶嵌和成熟的形态，以及是否能抵抗变性，这些都不完全清楚。为了探讨这些问题，我们将表达增强型绿色荧光蛋白（EGFP）的转基因小鼠与 rd1 小鼠（一种经典的视网膜变性小鼠模型）进行回交，以研究在视网膜变性背景下锥体双极细胞的发育和存活情况。我们的数据表明，锥体双极细胞的发育和变性都与锥体光感受器的正常活动无关。我们发现，第 7 型锥体双极细胞在视网膜表面实现了均匀的平铺，并形成了正常的树突和轴突分支，而不受锥体光感受器神经支配的影响。另一方面，与我们的中央到外周进展的信念相反，第 7 型锥体双极细胞的变性在整个视网膜上是空间均匀的，与锥体变性的时空模式无关。这些结果对设计更有效的治疗方法以恢复视网膜变性患者的视力具有重要意义。
