Photochemical Damage from Chronic 458-nm Laser exposures in an Artificially Pigmented hTERT-RPE1 Cell Line
AIR FORCE RESEARCH LAB BROOKS AFB TX OPTICAL RADIATION
Pagination or Media Count:
Artificially pigmented hTERT-RPE1 cells were exposed to a mode-locked or continuous wave CW laser at 458 run for one hour in a modified culture incubator. Exposure conditions were selected to give greatest likelihood of damage due to a photochemical mechanism, with interest in possible differences between CW and mode-locked damage thresholds. After post-exposure-recovery PER for either 1-hour or 24-hour, cells were concurrently stained with annexin V and 6-CFDA to determine if they had undergone necrosis or apoptosis. Alternatively, cells were stained with Ethidium Homodimer EthD-1 and Calcein AM to determine if they had undergone necrosis following 1 -hour and 24-hours PER. Preliminary results indicate that laser exposure induced some apoptosis following 1-hour PER, with irradiance required for apoptosis being lower than that for necrosis with mode-locked exposure conditions. Probit analysis yielded necrosis thresholds for cell culture following 1-hour PER using data compiled from both dye sets. CW exposures resulted in a lower threshold than mode-locked exposures for necrosis following 1-hour PER. A thermal model provided the predicted temperature rise in cell culture due to laser exposure. The thermal model validates our choice of laser parameters to obtain photochemical damage. Data following 24-hours PER were inconclusive. Considerations of cell migration are included in the interpretation of data and further improvements to methods when using live cell assays are recommended.
- Anatomy and Physiology
- Radiation and Nuclear Chemistry
- Lasers and Masers