Fig. 4: Tlcd3b knockout mice exhibit retinal degeneration and significant loss of cone photoreceptors.
From: Ceramide synthase TLCD3B is a novel gene associated with human recessive retinal dystrophy
(a) Electroretinography analysis shows scotopic a-wave is unaffected (p = 0.3) but the scotopic b-wave (p = 0.01) and photopic b-wave (p = 0.008) amplitudes are reduced in 7-month-old Tlcd3bKO/KO mice (n = 5) compared with Tlcd3b+/KO or wild-type (WT) control mice (n = 7). (b) Hematoxylin and eosin staining of retinal cross-sections shows overall retinal thinning in Tlcd3bKO/KO mice compared with wild-type control mice at 7 months of age. Scale bar = 20 μm. GCL ganglion cell layer, INL inner nuclear layer, IPL inner plexiform layer, IS inner segment, ONL outer nuclear layer, OPL outer plexiform layer, OS outer segment, RPE retinal pigment epithelium. (c) ONL measurements show a 20% reduction (p = 0.003) in ONL thickness in Tlcd3bKO/KO mice (n = 3) compared with wild-type or Tlcd3d+/KO control mice (n = 6) at 7 months of age (p = 0.002). Each dot represents an individual data point plotted over mean ± SEM. (d) INL measurements show no significant changes (p = 0.1) in INL thickness in Tlcd3bKO/KO mice (n = 3) compared with wild-type or Tlcd3b+/KO control mice (n = 6) at 7 months of age. Each dot represents an individual data point plotted over mean ± SEM. (e) Costaining of Fam57b preabsorbed antibody (red) and peanut agglutinin (PNA) (green) shows expression of Tlcd3b in cone photoreceptors. (e, f) PNA staining (green) shows loss of cones in Tlcd3bKO/KO retina compared with wild type in retinal sections (e) and retinal whole mounts (f). Scale bar = (e) 20 μm, (f) 50 μm. (g) Cones were counted in the dorsonasal (DN), dorsotemporal (DT), ventronasal (VN), and ventrotemporal (VT) regions of (f) PNA-stained (green) retinal whole mounts of 7-month-old Tlcd3bKO/KO mice (n = 3) and control mice (n = 3). (f, g) The number of cones is significantly reduced in the Tlcd3bKO/KO retina compared with controls (p = 0.003). Data are expressed as average number of cones per mm2 (mean ± SEM). Individual data points were plotted in addition to statistics. NS not significant, *p < 0.05, **p < 0.01, ***p < 0.001.
