Assessment of necroptosis in the retina in a repeated primary ocular blast injury mouse model

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Authors

  • Ella Courtie
  • Alexandra Bernardo-Colón
  • Gareth Essex
  • Tonia S. Rex
  • Richard J. Blanch

Colleges, School and Institutes

Abstract

Primary blast injury (caused by the initial rapid increase in pressure following an explosive blast) to the retina and optic nerve (ON) causes progressive visual loss and neurodegeneration. Military personnel are exposed to multiple low-overpressure blast waves, which may be in quick succession, such as during breacher training or in combat. We investigated the necroptotic cell death pathway in the retina in a mouse repeated primary ocular blast injury (rPBI) model using immunohistochemistry. We further evaluated whether intravitreal injections of a potent necroptosis inhibitor, Necrostatin-1s (Nec-1s), protects the retina and ON axons by retinal ganglion cells (RGC) counts, ON axonal counting and optical coherence tomography (OCT) analysis of vitreous haze. Receptor interacting protein kinase (RIPK) 3, increased in the inner plexiform layer 2 days post injury (dpi) and persisted until 14 dpi, whilst RIPK1 protein expression did not change after injury. The number of degenerating ON axons was increased at 28 dpi but there was no evidence of a reduction in the number of intact ON axons or RNA-binding protein with multiple splicing (RBPMS)+ RGC in the retina by 28 dpi in animals not receiving any intravitreal injections. But, when intravitreal injections (vehicle or Nec-1s) were given there was a significant reduction in RBPMS+ RGC numbers, suggesting that rPBI with intraocular injections is damaging to RGC. There were fewer RGC lost after Nec-1s than vehicle injection, but there was no effect of Nec-1s or vehicle treatment on the number of degenerating axons. OCT analysis demonstrated no effect of rPBI on vitreous haze, but intravitreal injection combined with rPBI increased vitreous haze (P = 0.004). Whilst necroptosis may be an active cell death signalling pathway after rPBI, its inhibition did not prevent cell death, and intravitreal injections in combination with rPBI increased vitreous inflammation and reduced RBPMS+ RGC numbers, implying intravitreal injection is not an ideal method for drug delivery after rPBI.

Bibliographic note

Funding Information: Supported by Fight for Sight PhD Studentship , grant number 1560/1561, DoD W81XWH-15-1-0096 , DoD W81XWH-17-2-0055 , NEI R01 EY022349 , NEI P30 EY008126 , Vanderbilt University Medical Center Cell Imaging Shared Resource core facility ( Clinical and Translational Science Award Grant UL1 RR024975 from National Center for Research Resources ), Research to Prevent Blindness Unrestricted Funds (VEI), Ret. Maj. General Stephen L. Jones, MD Fund, Potoscnak Family- CSC Research Fund , Ayers Research Fund in Regenerative Visual Neuroscience . Publisher Copyright: © 2020 Elsevier Ltd Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

Details

Original languageEnglish
Article number108102
JournalExperimental Eye Research
Volume197
Early online date6 Jun 2020
Publication statusPublished - Aug 2020

Keywords

  • Cell death, Necroptosis, Optic nerve, Primary blast injury, Retina, Retinal ganglion cells, Traumatic optic neuropathy