Chang Yao-Chuan, Walston Steven T, Chow Robert H, Weiland James D
University of Southern California, Los Angeles, ca 90033, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2016 Aug;2016:1316-1319. doi: 10.1109/EMBC.2016.7590949.
Virus-transduced calcium indicators are effective reporters of neural activity, offering the advantage of cell-specific labeling. To track the level of expression of genetically encoded calcium indicators (GECIs) in rodent retina, we developed a noninvasive imaging approach based on a custom-modified low-cost and simple fundus system that enabled us to monitor and characterize bright-field and fluorescence retinal image. The system clearly resolves individual retinal ganglion cells (RGCs) and axons. RGC fluorescence intensity and number of observable fluorescent cells show a consistent rising trend from week 1 to week 3 after viral injection, indicating a uniform increase of GCaMP6f expression. At defined time points, we prepared wholemount retina mounted on a transparent multielectrode array (MEA) and used calcium imaging to identify the optimal time for studying the responsiveness of RGCs to external electrical stimulation. The results show that the fluorescence-endoscopy fundus system is a powerful and widely accessible tool for evaluating fluorescence reporter expression.
病毒转导的钙指示剂是神经活动的有效报告分子，具有细胞特异性标记的优势。为了追踪啮齿动物视网膜中基因编码钙指示剂（GECIs）的表达水平，我们基于定制改良的低成本简易眼底系统开发了一种非侵入性成像方法，该方法使我们能够监测和表征明场和荧光视网膜图像。该系统能够清晰分辨单个视网膜神经节细胞（RGCs）及其轴突。病毒注射后第1周 至第3周，RGC荧光强度和可观察到的荧光细胞数量呈一致上升趋势，表明GCaMP6f表达均匀增加。在特定时间点，我们制备了安装在透明多电极阵列（MEA）上的视网膜全层标本，并使用钙成像来确定研究RGCs对外界电刺激反应性的最佳时间。结果表明，荧光内镜眼底系统是评估荧光报告基因表达的强大且广泛可用的工具。
