Excess Glutamate May Cause Dilation of Retinal Blood Vessels in Glutamate/Aspartate Transporter-Deficient Mice

Biomed Res Int. 2019 Nov 11:2019:6512195. doi: 10.1155/2019/6512195. eCollection 2019.

Abstract

Purpose: To investigate the longitudinal findings of fundus features and spectral-domain optical coherence tomography (SD-OCT) to characterize the morphologic features in a mouse model of defective glutamate/aspartate transporter (GLAST-/- mice).

Materials and methods: The fundus findings and SD-OCT images were longitudinally recorded at five time points from postnatal (P) 22 to P156 in GLAST-/- mice. As a control wild type, age-matched C57BL/6J mice were employed. The mouse retina was subdivided into five layers, and the thickness of each layer was longitudinally measured by InSight® using SD-OCT pictures. The SD-OCT findings were compared with the histologic appearances. The diameter of the retinal blood vessels was measured by the ImageJ® software program using SD-OCT images. The data were statistically compared between both age-matched mouse groups.

Results: The retinal blood vessels appeared more dilated in GLAST-/- mice than in wild-type mice. This tendency was statistically significant at all time points after P44 by analyses using SD-OCT images. The ganglion cell complex (GCC) and outer nuclear layer (ONL) were significantly thinner in GLAST-/- mice at all time points after P80 than in the wild-type mice. This tendency was more clearly indicated by SD-OCT than histologic sections.

Discussion: In the present study, we found for the first time the dilation of the retinal blood vessels and the thinning of the ONL in GLAST-/- mice, in addition to the thinning of the GCC.

MeSH terms

  • Amino Acid Transport System X-AG / genetics*
  • Amino Acid Transport System X-AG / metabolism
  • Animals
  • Disease Models, Animal
  • Electroretinography
  • Fundus Oculi
  • Glutamic Acid / metabolism*
  • Humans
  • Mice
  • Mice, Knockout
  • Photoreceptor Cells, Vertebrate / metabolism
  • Photoreceptor Cells, Vertebrate / pathology
  • Retina / diagnostic imaging
  • Retina / growth & development
  • Retina / metabolism*
  • Retinal Degeneration / genetics
  • Retinal Degeneration / metabolism
  • Retinal Degeneration / pathology
  • Retinal Vessels / diagnostic imaging
  • Retinal Vessels / growth & development
  • Retinal Vessels / metabolism*
  • Tomography, Optical Coherence

Substances

  • Amino Acid Transport System X-AG
  • Glutamic Acid