Tualang honey improves human corneal epithelial progenitor cell migration and cellular resistance to oxidative stress in vitro

PLoS One. 2014 May 6;9(5):e96800. doi: 10.1371/journal.pone.0096800. eCollection 2014.

Abstract

Stem cells with enhanced resistance to oxidative stress after in vitro expansion have been shown to have improved engraftment and regenerative capacities. Such cells can be generated by preconditioning them with exposure to an antioxidant. In this study we evaluated the effects of Tualang honey (TH), an antioxidant-containing honey, on human corneal epithelial progenitor (HCEP) cells in culture. Cytotoxicity, gene expression, migration, and cellular resistance to oxidative stress were evaluated. Immunofluorescence staining revealed that HCEP cells were holoclonal and expressed epithelial stem cell marker p63 without corneal cytokeratin 3. Cell viability remained unchanged after cells were cultured with 0.004, 0.04, and 0.4% TH in the medium, but it was significantly reduced when the concentration was increased to 3.33%. Cell migration, tested using scratch migration assay, was significantly enhanced when cells were cultured with TH at 0.04% and 0.4%. We also found that TH has hydrogen peroxide (H2O2) scavenging ability, although a trace level of H2O2 was detected in the honey in its native form. Preconditioning HCEP cells with 0.4% TH for 48 h showed better survival following H2O2-induced oxidative stress at 50 µM than untreated group, with a significantly lower number of dead cells (15.3 ± 0.4%) were observed compared to the untreated population (20.5 ± 0.9%, p<0.01). Both TH and ascorbic acid improved HCEP viability following induction of 100 µM H2O2, but the benefit was greater with TH treatment than with ascorbic acid. However, no significant advantage was demonstrated using 5-hydroxymethyl-2-furancarboxaldehyde, a compound that was found abundant in TH using GC/MS analysis. This suggests that the cellular anti-oxidative capacity in HCEP cells was augmented by native TH and was attributed to its antioxidant properties. In conclusion, TH possesses antioxidant properties and can improve cell migration and cellular resistance to oxidative stress in HCEP cells in vitro.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily G, Member 2
  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / metabolism
  • Actins / genetics
  • Actins / metabolism
  • Cell Movement / drug effects
  • Cell Survival / drug effects
  • Cells, Cultured
  • Connexin 43 / genetics
  • Connexin 43 / metabolism
  • Epithelium, Corneal / cytology*
  • Free Radical Scavengers / chemistry
  • Furans / analysis
  • Furans / isolation & purification
  • Furans / pharmacology
  • Gas Chromatography-Mass Spectrometry
  • Honey / analysis*
  • Humans
  • Hydrogen Peroxide / chemistry
  • Hydrogen Peroxide / toxicity
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism
  • Oxidative Stress* / drug effects
  • RNA, Messenger / metabolism
  • Stem Cells / cytology
  • Stem Cells / drug effects*
  • Stem Cells / metabolism

Substances

  • 5-hydroxymethyl-2-furancarboxaldehyde
  • ABCG2 protein, human
  • ATP Binding Cassette Transporter, Subfamily G, Member 2
  • ATP-Binding Cassette Transporters
  • Actins
  • Connexin 43
  • Free Radical Scavengers
  • Furans
  • Neoplasm Proteins
  • RNA, Messenger
  • Hydrogen Peroxide

Grants and funding

This project was supported by the Universiti Sains Malaysia Short Term Grant (304/CIPPT/6311032)(http://www.research.usm.my/?tag=22) and Advanced Medical and Dental Institute. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.