Fig. 7: Light responses in transplanted iPSC-retinas by ex vivo electrophysiology assay.
a Scheme of ex vivo electrophysiology assay using MEA to evaluate the light responses in transplanted iPSC-retinas. iPSC-S17-derived retinal sheets were transplanted in the subretinal space in RD-nude rats. Transplanted and non-transplanted rat retinas were mounted on the MEA electrodes for electrophysiological recording. During the recording, light stimuli were conducted in different intensities (weak, medium, strong), and the rat retinas were incubated in Ames’ medium (Before), followed by addition of L-AP4 (L-AP4), and washout of L-AP4 (After washout). b–d Representative results of MEA analysis. (b) Differential interference contrast (DIC) image of a RD-nude rat retina mounted on the MEA. Engrafted area was indicated by red dotted line. Scale bar: 1 mm. c, d Peri-stimulus time histograms to examine the RGC-spike counts during strong light stimuli (12.84 log photons/cm2/s). The X-axis and Y-axis represent the time and average RGC-spike count, respectively. Recording data for iPSC-S17-derived retinal sheet-transplanted rat retinas (Transplanted; upper) and non-transplanted rat retinas (Non-transplanted; lower) in the three conditions (Before, L-AP4, After washout) are shown. Multiple electrode recording data are shown in (c) and representative data (red box in c) are shown in (d). Yellow box in (c, d): light stimuli. Red arrows in (d): start timing of light stimuli. e RGC light response probabilities. Control non-transplanted rat retinas (Control; n = 12) and iPSC-S17-derived retinal sheet-transplanted rat retinas (Transplanted; n = 12) were subjected to MEA analysis to evaluate the RGC responses to light stimulation. Dots and bars show the per sample (recorded rat retina) summary of the collected data. Dot: RGC light response probability estimated by statistical modeling (Bayesian statistical inference with Markov Chain Monte Carlo sampling). Bar: 89% confidence interval.
