The generation of 4-hydroxynonenal, an electrophilic lipid peroxidation end product, in rabbit cornea organ cultures treated with UVB light and nitrogen mustard

Toxicol Appl Pharmacol. 2013 Oct 15;272(2):345-55. doi: 10.1016/j.taap.2013.06.025. Epub 2013 Jul 9.


The cornea is highly sensitive to oxidative stress, a process that can lead to lipid peroxidation. Ultraviolet light B (UVB) and nitrogen mustard (mechlorethamine) are corneal toxicants known to induce oxidative stress. Using a rabbit air-lifted corneal organ culture model, the oxidative stress responses to these toxicants in the corneal epithelium was characterized. Treatment of the cornea with UVB (0.5 J/cm(2)) or nitrogen mustard (100 nmol) resulted in the generation of 4-hydroxynonenal (4-HNE), a reactive lipid peroxidation end product. This was associated with increased expression of the antioxidant, heme oxygenase-1 (HO-1). In human corneal epithelial cells in culture, addition of 4-HNE or 9-nitrooleic acid, a reactive nitrolipid formed during nitrosative stress, caused a time-dependent induction of HO-1 mRNA and protein; maximal responses were evident after 10h with 30 μM 4-HNE or 6h with 10 μM 9-nitrooleic acid. 4-HNE and 9-nitrooleic acid were also found to activate Erk1/2, JNK and p38 MAP kinases, as well as phosphoinositide-3-kinase (PI3)/Akt. Inhibition of p38 blocked 4-HNE- and 9-nitrooleic acid-induced HO-1 expression. Inhibition of Erk1/2, and to a lesser extent, JNK and PI3K/Akt, suppressed only 4-HNE-induced HO-1, while inhibition of JNK and PI3K/Akt, but not Erk1/2, partly reduced 9-nitrooleic acid-induced HO-1. These data indicate that the actions of 4-HNE and 9-nitrooleic acid on corneal epithelial cells are distinct. The sensitivity of corneal epithelial cells to oxidative stress may be an important mechanism mediating tissue injury induced by UVB or nitrogen mustard.

Keywords: 4-Hydroxynonenal; 9-Nitrooleic acid; Cornea; Nitrogen mustard; Nitrosative stress; UVB.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aldehydes / metabolism*
  • Aldehydes / toxicity
  • Animals
  • Cornea / drug effects
  • Cornea / metabolism*
  • Cornea / radiation effects
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Epithelial Cells / pathology
  • Heme Oxygenase-1 / biosynthesis
  • Humans
  • Lipid Peroxidation* / drug effects
  • Lipid Peroxidation* / radiation effects
  • Lipid Peroxides / metabolism*
  • Lipid Peroxides / toxicity
  • Mechlorethamine / toxicity*
  • Organ Culture Techniques
  • Oxidative Stress / drug effects
  • Oxidative Stress / radiation effects
  • Rabbits
  • Time Factors
  • Ultraviolet Rays / adverse effects*


  • Aldehydes
  • Lipid Peroxides
  • Mechlorethamine
  • Heme Oxygenase-1
  • 4-hydroxy-2-nonenal