Taurine deficiency damages retinal neurones: cone photoreceptors and retinal ganglion cells

Amino Acids. 2012 Nov;43(5):1979-93. doi: 10.1007/s00726-012-1273-3. Epub 2012 Apr 4.

Abstract

In 1970s, taurine deficiency was reported to induce photoreceptor degeneration in cats and rats. Recently, we found that taurine deficiency contributes to the retinal toxicity of vigabatrin, an antiepileptic drug. However, in this toxicity, retinal ganglion cells were degenerating in parallel to cone photoreceptors. The aim of this study was to re-assess a classic mouse model of taurine deficiency following a treatment with guanidoethane sulfonate (GES), a taurine transporter inhibitor to determine whether retinal ganglion cells are also affected. GES treatment induced a significant reduction in the taurine plasma levels and a lower weight increase. At the functional level, photopic electroretinograms were reduced indicating a dysfunction in the cone pathway. A change in the autofluorescence appearance of the eye fundus was explained on histological sections by an increased autofluorescence of the retinal pigment epithelium. Although the general morphology of the retina was not affected, cell damages were indicated by the general increase in glial fibrillary acidic protein expression. When cell quantification was achieved on retinal sections, the number of outer/inner segments of cone photoreceptors was reduced (20 %) as the number of retinal ganglion cells (19 %). An abnormal synaptic plasticity of rod bipolar cell dendrites was also observed in GES-treated mice. These results indicate that taurine deficiency can not only lead to photoreceptor degeneration but also to retinal ganglion cell loss. Cone photoreceptors and retinal ganglion cells appear as the most sensitive cells to taurine deficiency. These results may explain the recent therapeutic interest of taurine in retinal degenerative pathologies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport / drug effects
  • Disease Models, Animal
  • Electroretinography
  • Eye Proteins / genetics*
  • Eye Proteins / metabolism
  • Gene Expression / drug effects
  • Glial Fibrillary Acidic Protein / genetics*
  • Glial Fibrillary Acidic Protein / metabolism
  • Guanidines / pharmacology
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Neuronal Plasticity / drug effects
  • Retinal Cone Photoreceptor Cells / drug effects
  • Retinal Cone Photoreceptor Cells / metabolism
  • Retinal Cone Photoreceptor Cells / pathology*
  • Retinal Degeneration / chemically induced
  • Retinal Degeneration / metabolism
  • Retinal Degeneration / pathology*
  • Retinal Ganglion Cells / drug effects
  • Retinal Ganglion Cells / metabolism
  • Retinal Ganglion Cells / pathology*
  • Retinal Pigment Epithelium / drug effects
  • Retinal Pigment Epithelium / metabolism
  • Retinal Pigment Epithelium / pathology*
  • Taurine / antagonists & inhibitors
  • Taurine / deficiency*

Substances

  • Eye Proteins
  • Glial Fibrillary Acidic Protein
  • Guanidines
  • Taurine