In vivo imaging of murine retinal ganglion cells

Current methods for in vivo retinal ganglion cells (RGCs) imaging involve either retrograde or intravitreal injection of chemical or biological tracers, which are invasive and may require repeated injection for serial long-term assessment. We have developed a confocal scanning laser ophthalmoscope technique (blue-light CSLO or bCSLO) to image retinal ganglion cells (RGCs) in mice expressing cyan fluorescent protein under the control of a Thy-1 promoter. Fluorescent spots corresponding to CFP-expressing retinal ganglion cells were discernable with the bCSLO. 96.1+/-2.6% of CFP expressing cells also were retrograde labeled with DiI indicating the bCSLO imaged fluorescent spots are RGCs. The imaging of Thy-1 promoter-driven CFP expression in these mice could serve as a sensitive indicator to reflect the integrity of RGCs, and provides a non-invasive method for longitudinal study of the mechanism of RGC degeneration and the effect of neuroprotective agents.