DNA DAMAGE RESPONSE OF EX-VIVO PORCINE EYE LENSES IN ORGANCULTURE AND IN-VITRO CULTURED LENS EPITHELIAL CELLS TO IONIZING RADIATION

Abstract

Astronauts on space missions, especially on long-term missions to Moon or Mars have a higher risk for the expression of radiation late effects such as cancer or sub-capsular cortical eye lens opacities. This is due to higher dose and different patterns of cellular energy deposition from high-linear-energy-transfer (LET) components of galactic cosmic radiation in space than that of terrestrial low-LET radiation on Earth. The eye lens is considered to be a radiation sensitive organ with radiation induced cataract to occur with a threshold absorbed dose of 0.5 Gy of sparsely ionizing radiation. For terrestrial occupational radiation lens exposure limit is set to yearly 20 mSv by the International Commission on Radiological Protection (ICRP, Statement on tissue reactions, Ottawa, Canada, 2011). Doses perceived by astronauts are much higher: in average 150 mSv per year on the International Space Station (ISS) and 1.2 to 1.4 mSv per day on Apollo and Skylab missions (Cucinotta FA, Manuel FK, Jones J, Iszard G, Murrey J, Djojonegro B, Wear M. Space radiation and cataracts in astronauts. Radiat Res. 156:460-466, 2001).