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Updated: Jun 23, 2026
09:31
Determining the Toxicity of UV Radiation and Chemicals on Primary and Immortalized Human Corneal Epithelial Cells
Published on: July 22, 2021
Hydrogen peroxide causes mitochondrial DNA damage in corneal epithelial cells
Shari R Atilano1, Marilyn Chwa, Dae W Kim
1Department of Ophthalmology, University of California, Irvine Medical Center, Irvine, CA 92868, USA.
Cornea
|May 5, 2009
Summary
Hydrogen peroxide significantly degrades mitochondrial DNA (mtDNA) in human corneal cells in vitro. Despite increased oxidative damage in keratoconus (KC) corneas, mtDNA integrity in KC and normal (NL) epithelial cells was comparable.
Area of Science:
- Ophthalmology
- Molecular Biology
- Cell Biology
Background:
- Mitochondrial DNA (mtDNA) is crucial for cellular energy production.
- Oxidative stress is implicated in various ocular diseases, including keratoconus (KC).
- Hydrogen peroxide (H2O2) is a known inducer of oxidative stress.
Purpose of the Study:
- To investigate the impact of H2O2 on mtDNA integrity in cultured human corneal epithelial cells.
- To compare mtDNA integrity between epithelial cells from normal (NL) and KC corneas.
Main Methods:
- Cultured human corneal epithelial cells (hTCEpi) were exposed to H2O2 at different pH levels.
- Immunohistochemistry for 8-hydroxy-2'-deoxyguanosine (8-OH-dG) was used to assess oxidative damage.
- Mitochondrial DNA integrity was analyzed using long-extension PCR (LX-PCR), and control regions were sequenced.
Main Results:
- H2O2 exposure significantly reduced full-length LX-PCR mtDNA in cultured cells (54% at pH 7.0, 44% at pH 5.0).
- KC corneas showed 8-OH-dG in all epithelial layers, while NL corneas had it only in superficial layers.
- Despite higher oxidative damage markers in KC, comparable levels of full-length mtDNA and similar mtDNA control region sequences were found in isolated KC and NL epithelial cells.
Conclusions:
- Hydrogen peroxide demonstrably degrades mtDNA in vitro.
- While KC epithelium exhibits greater oxidative damage, the overall mtDNA integrity in KC and NL epithelial cells is similar.
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