Medium-mediated effects increase cell killing in a human keratinocyte cell line exposed to solar-simulated radiation.
OBJECTIVE
The objective of this study was to investigate whether cell culture medium is a biologically relevant exposure medium that can be employed in non-ionising photobiological investigations.


METHODS
The effect of solar-simulated irradiation on cell culture medium and its ability to elicit cell death was studied. The role of reactive oxygen species (ROS), cell secreted factors, and the contribution of individual components of the medium were investigated.


RESULTS
Cell death was found to be primarily mediated through the formation of ROS via riboflavin photosensitisation and degradation in the cell culture medium. Phenol red was found to significantly reduce the cell killing ability of riboflavin. Exposures in riboflavin-free medium resulted in significantly increased cell survival compared to identical exposures in riboflavin containing medium.


CONCLUSIONS
This study has shown that solar radiation toxicity is augmented by cell culture medium due to the presence of riboflavin. Results suggest that exposures performed in phenol red-free medium may serve to increase phototoxic effects if riboflavin is present. Riboflavin-free media is recommended for solar radiation investigations to eliminate concerns regarding riboflavin photosensitisation and nutrient deprivation.
Maguire
Alanna
A
Radiation and Environmental Science Centre (RESC), Focas Research Institute, Dublin Institute of Technology, Ireland.
Morrissey
Brian
B
Walsh
James E
JE
Lyng
Fiona M
FM
D000975:Antioxidants / Q000378:metabolism; D016923:Cell Death / Q000528:radiation effects*; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D003114:Colony-Forming Units Assay; D003470:Culture Media / Q000737:chemistry / Q000528:radiation effects; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D010637:Phenolsulfonphthalein / Q000737:chemistry / Q000528:radiation effects; D017319:Photosensitizing Agents / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012256:Riboflavin / Q000378:metabolism / Q000528:radiation effects; D013053:Spectrophotometry; D013472:Sunlight / Q000009:adverse effects*
D000975:Antioxidants; D003470:Culture Media; D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; D010637:Phenolsulfonphthalein; D012256:Riboflavin