Protective effects of bilberry and lingonberry extracts against blue light-emitting diode light-induced retinal photoreceptor cell damage in vitro

BMC Complement Altern Med. 2014 Apr 2;14:120. doi: 10.1186/1472-6882-14-120.

Abstract

Background: Blue light is a high-energy or short-wavelength visible light, which induces retinal diseases such as age-related macular degeneration and retinitis pigmentosa. Bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea) contain high amounts of polyphenols (anthocyanins, resveratrol, and proanthocyanidins) and thus confer health benefits. This study aimed to determine the protective effects and mechanism of action of bilberry extract (B-ext) and lingonberry extract (L-ext) and their active components against blue light-emitting diode (LED) light-induced retinal photoreceptor cell damage.

Methods: Cultured murine photoreceptor (661 W) cells were exposed to blue LED light following treatment with B-ext, L-ext, or their constituents (cyanidin, delphinidin, malvidin, trans-resveratrol, and procyanidin B2). 661 W cell viability was assessed using a tetrazolium salt (WST-8) assay and Hoechst 33342 nuclear staining, and intracellular reactive oxygen species (ROS) production was determined using CM-H2DCFDA after blue LED light exposure. Activation of p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor-kappa B (NF-κB), and LC3, an ubiquitin-like protein that is necessary for the formation of autophagosomes, were analyzed using Western blotting. Caspase-3/7 activation caused by blue LED light exposure in 661 W cells was determined using a caspase-3/7 assay kit.

Results: B-ext, L-ext, NAC, and their active components improved the viability of 661 W cells and inhibited the generation of intracellular ROS induced by blue LED light irradiation. Furthermore, B-ext and L-ext inhibited the activation of p38 MAPK and NF-κB induced by blue LED light exposure. Finally, B-ext, L-ext, and NAC inhibited caspase-3/7 activation and autophagy.

Conclusions: These findings suggest that B-ext and L-ext containing high amounts of polyphenols exert protective effects against blue LED light-induced retinal photoreceptor cell damage mainly through inhibition of ROS production and activation of pro-apoptotic proteins.

MeSH terms

  • Animals
  • Anthocyanins / chemistry
  • Anthocyanins / pharmacology
  • Anthocyanins / therapeutic use
  • Apoptosis / drug effects
  • Apoptosis Regulatory Proteins / metabolism
  • Caspase 3 / metabolism
  • Cell Survival / drug effects
  • In Vitro Techniques
  • Light*
  • Mice
  • NF-kappa B / metabolism
  • Photoreceptor Cells, Vertebrate / drug effects*
  • Photoreceptor Cells, Vertebrate / metabolism
  • Photoreceptor Cells, Vertebrate / radiation effects
  • Phytotherapy*
  • Plant Extracts / pharmacology
  • Plant Extracts / therapeutic use
  • Polyphenols / pharmacology*
  • Polyphenols / therapeutic use
  • Reactive Oxygen Species / metabolism
  • Resveratrol
  • Retina / drug effects
  • Retina / metabolism
  • Retina / radiation effects
  • Retinal Diseases / drug therapy
  • Retinal Diseases / etiology
  • Retinal Diseases / metabolism*
  • Stilbenes / pharmacology
  • Stilbenes / therapeutic use
  • Tetrazolium Salts
  • Vaccinium myrtillus / chemistry*
  • Vaccinium vitis-idaea / chemistry*
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H tetrazolium monosodium salt
  • Anthocyanins
  • Apoptosis Regulatory Proteins
  • NF-kappa B
  • Plant Extracts
  • Polyphenols
  • Reactive Oxygen Species
  • Stilbenes
  • Tetrazolium Salts
  • malvidin
  • cyanidin
  • Vaccinium myrtillus extract
  • p38 Mitogen-Activated Protein Kinases
  • Caspase 3
  • delphinidin
  • Resveratrol