Oxidative stress induced age dependent meibomian gland dysfunction in Cu, Zn-superoxide dismutase-1 (Sod1) knockout mice

PLoS One. 2014 Jul 18;9(7):e99328. doi: 10.1371/journal.pone.0099328. eCollection 2014.

Abstract

Purpose: The purpose of our study was to investigate alterations in the meibomian gland (MG) in Cu, Zn-Superoxide Dismutase-1 knockout (Sod1-/-) mouse.

Methods: Tear function tests [Break up time (BUT) and cotton thread] and ocular vital staining test were performed on Sod1-/- male mice (n = 24) aged 10 and 50 weeks, and age and sex matched wild-type (+/+) mice (n = 25). Tear and serum samples were collected at sacrifice for inflammatory cytokine assays. MG specimens underwent Hematoxylin and Eosin staining, Mallory staining for fibrosis, Oil Red O lipid staining, TUNEL staining, immunohistochemistry stainings for 4HNE, 8-OHdG and CD45. Transmission electron microscopic examination (TEM) was also performed.

Results: Corneal vital staining scores in the Sod1-/- mice were significantly higher compared with the wild type mice throughout the follow-up. Tear and serum IL-6 and TNF-α levels also showed significant elevations in the 10 to 50 week Sod1-/- mice. Oil Red O staining showed an accumulation of large lipid droplets in the Sod1-/- mice at 50 weeks. Immunohistochemistry revealed both increased TUNEL and oxidative stress marker stainings of the MG acinar epithelium in the Sod1-/- mice compared to the wild type mice. Immunohistochemistry staining for CD45 showed increasing inflammatory cell infiltrates from 10 to 50 weeks in the Sod1-/- mice compared to the wild type mice. TEM revealed prominent mitochondrial changes in 50 week Sod1-/- mice.

Conclusions: Our results suggest that reactive oxygen species might play a vital role in the pathogensis of meibomian gland dysfunction. The Sod1-/- mouse appears to be a promising model for the study of reactive oxygen species associated MG alterations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Apoptosis
  • DNA Damage
  • Dry Eye Syndromes / etiology
  • Dry Eye Syndromes / physiopathology
  • Epithelium, Corneal / pathology
  • Inflammation
  • Interleukin-6 / blood
  • Lipid Peroxidation
  • Male
  • Meibomian Glands / enzymology
  • Meibomian Glands / physiopathology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Oxidative Stress*
  • Superoxide Dismutase / deficiency*
  • Superoxide Dismutase-1
  • Tears / chemistry
  • Tears / metabolism
  • Tumor Necrosis Factor-alpha / blood

Substances

  • Interleukin-6
  • Tumor Necrosis Factor-alpha
  • interleukin-6, mouse
  • Sod1 protein, mouse
  • Superoxide Dismutase
  • Superoxide Dismutase-1

Grant support

This work was supported by funds from Japan Society for the Promotion of Science (Grant No. 22791694) (http://www.jsps.go.jp/english/e-grants/) and Johnson and Johnson Vision Care Company (http://www.jnj.co.jp/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.