Enhanced Endothelin-1 Mediated Vasoconstriction of the Ophthalmic Artery May Exacerbate Retinal Damage after Transient Global Cerebral Ischemia in Rat

PLoS One. 2016 Jun 20;11(6):e0157669. doi: 10.1371/journal.pone.0157669. eCollection 2016.

Abstract

Cerebral vasculature is often the target of stroke studies. However, the vasculature supplying the eye might also be affected by ischemia. The aim of the present study was to investigate if the transient global cerebral ischemia (GCI) enhances vascular effect of endothelin-1 (ET-1) and 5-hydroxytryptamine/serotonin (5-HT) on the ophthalmic artery in rats, leading to delayed retinal damage. This was preformed using myography on the ophthalmic artery, coupled with immunohistochemistry and electroretinogram (ERG) to assess the ischemic consequences on the retina. Results showed a significant increase of ET-1 mediated vasoconstriction at 48 hours post ischemia. The retina did not exhibit any morphological changes throughout the study. However, we found an increase of GFAP and vimentin expression at 72 hours and 7 days after ischemia, indicating Müller cell mediated gliosis. ERG revealed significantly decreased function at 72 hours, but recovered almost completely after 7 days. In conclusion, we propose that the increased contractile response via ET-1 receptors in the ophthalmic artery after 48 hours may elicit negative retinal consequences due to a second ischemic period. This may exacerbate retinal damage after ischemia as illustrated by the decreased retinal function and Müller cell activation. The ophthalmic artery and ET-1 mediated vasoconstriction may be a valid and novel therapeutic target after longer periods of ischemic insults.

MeSH terms

  • Animals
  • Chickens
  • Electroretinography
  • Endothelin-1 / metabolism*
  • Glial Fibrillary Acidic Protein / metabolism
  • Immunohistochemistry
  • Ischemic Attack, Transient / pathology*
  • Male
  • Night Vision
  • Ophthalmic Artery / metabolism*
  • Ophthalmic Artery / physiology*
  • Rats, Wistar
  • Retina / metabolism*
  • Retina / pathology*
  • Vasoconstriction*
  • Vimentin / metabolism

Substances

  • Endothelin-1
  • Glial Fibrillary Acidic Protein
  • Vimentin

Grants and funding

This work was supported by Hjärt-Lungfonden award number 20130271 (www.hjart-lungfonden.se) and Vetenskapsrådet (http://www.vr.se/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.