Electrophysiological Evaluation of Mouse ES and iPS Derived Retina-like Sheet Transplantation in Retinal Degeneration Mouse

Abstract

Purpose: : Retinal sheet transplantation is a promising technique for the treatment of retinal degenerative diseases. However whether the maturation of transplanted cells as photoreceptors and the functional synaptic formation to downstream targets in host retinas are still unclear. The aim of this study was to seek for a methodology to characterize the physiological properties of transplanted retinal sheets and to evaluate the restoration of light-evoked retinal ganglion cell response after transplantation using multi-electrode array (MEA).

Methods: : Rx-GFP mES and Nrl-GPF iPS derived retina-like sheets were transplanted in the subretinal space of retinal degeneration (rd1) mouse. Transplanted retinas from dark-adapted recipient mice were prepared for the in vitro electrophysiological study. For MEA recording, a total 8x8 electrodes in 1.2mm square were positioned against each retina, and electrical responses were recorded from the cells in ganglion cell layer with each probe after light stimulation.

Results: : Transplanted mice retina showed spontaneous bursts of ganglion cell action potentials as well as recordable microERGs over the transplant with and without light stimulation. By performing spike sorting on the recordings from each channel, we could simultaneously pick up the single-neuron action potentials from more than 100 ganglion cells including the ones over transplant. Light-evoked ganglion cell responses could neither be recorded in areas outside the transplant in transplant-recipient eyes and age-matched control retina. The high rate spontaneous action potentials by ganglion cells remained even in the transplanted area.

Conclusions: : We could detect the ganglion cell action potentials over the transplanted area at a single ganglion cell level. We will further seek for a potential to pick up light responses from the ganglion cells possibly connected to photoreceptors in transplanted retinal sheets.

Keywords: transplantation • retinitis • electrophysiology: non-clinical