April 2014
Volume 55, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2014
Microglial Activation and Translocator Protein Expression in a Rat Optic Nerve Crush Model
Author Affiliations & Notes
  • Nobuharu Asai
    Bioengineering Institute R&D Division, NIDEK Co Ltd, Gamagori, Japan
  • Masayoshi Nakatani
    Bioengineering Institute R&D Division, NIDEK Co Ltd, Gamagori, Japan
  • Takao Nakamura
    Bioengineering Institute R&D Division, NIDEK Co Ltd, Gamagori, Japan
  • Kan Ohtsuki
    Bioengineering Institute R&D Division, NIDEK Co Ltd, Gamagori, Japan
  • Footnotes
    Commercial Relationships Nobuharu Asai, None; Masayoshi Nakatani, None; Takao Nakamura, None; Kan Ohtsuki, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science April 2014, Vol.55, 2267. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Nobuharu Asai, Masayoshi Nakatani, Takao Nakamura, Kan Ohtsuki; Microglial Activation and Translocator Protein Expression in a Rat Optic Nerve Crush Model. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2267.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose: Microglia are located in central nerve system including retina. In normal conditions, they have a ramified morphology. After injury, microglia are activated and their morphology becomes amoeboid. This study was undertaken to characterize the reaction of microglia during degeneration of the optic nerve and retinal ganglion cells (RGCs).

Methods: Optic nerve injury and RGC death were induced by optic nerve crush (ONC) in adult male Brown Norway rats. Retinal thicknesses were monitored using spectral-domain optical coherence tomography. At 1 to 14 days after ONC, the retinas were isolated, and cells positive for Brn-3a (a marker of RGCs) were counted. Microglial morphology was observed by using immunohistochemistry for Iba-1, a marker of microglia. Translocator protein (TSPO) mRNA expression levels were assessed by using semiquantitative PCR.

Results: The thickness of ganglion cell complex (GCC) 400 μm from the optic nerve head (ONH) was 89.6 ± 1.6 mm in naive retinas. The GCC thickness was visibly reduced 14 days after ONC (71.7 ± 0.6 μm). The number of Brn-3a positive RGCs decreased slowly over the 14 days (104% ± 2%, 90% ± 5%, 42% ± 2% and 7% ± 1% relative to the numbers in naive retinas, at 1, 3, 7, and 14 days, respectively). The pattern of microglial staining was altered around part of the ONH 3 days after ONC. This alteration of microglia had spread entirely around the ONH at 7 and 14 days after ONC. TSPO mRNA expression was 50% higher than the naive level at 1 day after ONC, and this high expression continued for at least 7 days.

Conclusions: In an ONC model, microglia were activated before reductions were seen in the GCC thickness and number of RGCs. These results suggest that microglia respond to RGC injury at an early stage. Because microglial activation and up-regulation of TSPO expression continued during the progression of tissue degeneration and RGC death, these events might serve as biomarkers of retinal diseases such as glaucoma.

Keywords: 595 microglia • 629 optic nerve • 554 immunohistochemistry  
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×