Curcumin protects retinal pigment epithelial cells against oxidative stress via induction of heme oxygenase-1 expression and reduction of reactive oxygen

Mol Vis. 2012:18:901-8. Epub 2012 Apr 11.

Abstract

Purpose: To determine whether curcumin induces expression of the defensive enzyme heme oxygenase-1 (HO-1) and protects cells against oxidative stress in cultured human retinal pigment epithelial cells.

Methods: Effective concentrations and toxicities of curcumin were determined after 3 h of curcumin treatment with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Confluent human retinal pigment epithelium cell lines (ARPE-19) were preincubated with curcumin and oxidatively challenged with H(2)O(2). HO-1 expression was determined with western blot analysis. To confirm the protective role of HO-1 in oxidative stress, small interfering RNA (siRNA) against HO-1 or inhibitor of HO-1 was treated with curcumin in retinal pigment epithelium cells. Intracellular levels of reactive oxygen species (ROS) were measured with flow cytometry and confocal microscopy. Apoptosis was evaluated with Annexin V-fluoroscein isothiocyanate staining.

Results: Curcumin had little cytotoxicity at concentrations less than 30 μM, and HO-1 expression was the highest at the 15 μM concentration. At this concentration, curcumin also increased the cytoprotective effect against the oxidative stress of H(2)O(2) through the reduction of ROS levels in human retinal pigment epithelial cells. Curcumin's effect on the reduction of ROS was mediated by the increase in HO-1 expression.

Conclusions: Curcumin upregulated the oxidative stress defense enzyme HO-1 and may protect human retinal pigment epithelial cells against oxidative stress by reducing ROS levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Apoptosis / drug effects
  • Cell Line
  • Cell Survival / drug effects
  • Curcumin / pharmacology*
  • Cytoprotection
  • Epithelial Cells / cytology
  • Epithelial Cells / drug effects*
  • Epithelial Cells / metabolism
  • Gene Expression / drug effects
  • Heme Oxygenase-1 / antagonists & inhibitors
  • Heme Oxygenase-1 / genetics
  • Heme Oxygenase-1 / metabolism*
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Imidazoles / pharmacology
  • Oxidative Stress / drug effects
  • Pyridines / pharmacology
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Reactive Oxygen Species / metabolism
  • Retinal Pigment Epithelium / cytology
  • Retinal Pigment Epithelium / drug effects*
  • Retinal Pigment Epithelium / metabolism
  • Up-Regulation

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Imidazoles
  • Pyridines
  • RNA, Small Interfering
  • Reactive Oxygen Species
  • Hydrogen Peroxide
  • Heme Oxygenase-1
  • Curcumin
  • SB 203580