Abstract
Purpose:
Characterization of blue light and UV-B radiation effects on primary porcine lens epithelial cells (LEC) under different growth conditions and its prevention by Eupharasia extracts. Investigation of proliferative versus toxic effects of short wave radiation in culture.
Methods:
Lens epithelial flat mounts were dissected from porcine eyes freshly obtained from the slaughter house, placed in petri dishes, covered with EpiCM medium (SciencCell Sc-4101: 2% FCS, 1% P/S, 1% growth factors, GF) and incubated at 37°C in 5% CO2 until close to confluence. Thereafter cells were detached with accutase and transferred into T-75 collagen coated flasks (300.000 cells / flask). At a population doubling rate (PD) of 4 - 4,5 LECs were harvested and aliquots frozen at -80°C. For radiation experiments, 900 cells per well were seeded and cultivated in EpiCM medium + GF until PD 7 at which radiation exposure started. Irradiation was performed using a neoBLUE blanket (450 - 475 nm, blue light, 24 h) or a Waldmann UV-B lamp (290 - 320 nm, 9/18 mJ/cm2 30/60 sec). To investigate the influence GF on radiation sensitivity, cells were first cultivated in medium with GF until confluence, than medium was exchanged to GF free and cultivation was continued for 6 days before radiation exposure started. Radiation damage was determined with the cytotoxicity detection kit (Roche 11544793001) and the MTT test (Merck Millipore). Commercially available Euphrasia extracts (Augentrost, Weleda) were added to the medium in various concentrations to determine potential cytotoxicity or protection.
Results:
Both radiation exposures interfered with cell metabolism and growth, however, as expected UV-B is much more damaging than blue light. Independent of the wave length LECs grown with GF proved to be significantly more radiation sensitive than LECs grown in GF free medium. Euphrasia extracts demonstrated a low cytotoxicity and a good protective effect on LECs against radiation damage.
Conclusions:
Primary porcine LECs provided a reproducible tissue culture model to study radiation toxicity from blue light and UV-B in vitro. Radiation sensitivity of LECS is strongly influenced by the proliferative state of the cells. Euphrasia extracts demonstrate a radiation protective potential against blue light damage.<br />