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J. R. Trevithick, T. M. Dzialoszynski, C. Carrasquilla; Modeling Astronaut Cataract Risk Reduction: Radiation Effects on Lenses Exposed to 60Co, Proton and Neutron Beams. Invest. Ophthalmol. Vis. Sci. 2008;49(13):2267. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To explore the role of heat shock proteins and related chaperone and protective proteins in porcine lenses exposed to elevated temperature, or different types of radiation.
Pig eyes obtained from a local abattoir were dissected aseptically and the lenses incubated in medium M199 without serum for 4 days to stabilize. Those with protein leakage less than 10 mg/L were taken for heat shock. Lenses were exposed to radiation stress by exposure to 60Co γ-radiation, 74 MeV protons, or a neutron spectrum similar to the atmospheric spectrum of neutrons from 1- 400 MeV . Heat stress was performed by incubation for 1 hr in M199 wthout serum at a variety of temperatures from 37C to 55C. After post-stress incubation for 24 hr., the lenses were weighed and homogenized. The homogenates were analyzed as appropriate for Hsps 90, 70, 47, 27, HSF1, Akt, MnSOD, Cu/ZnSOD, and αB-crystallin by western blotting. ScantoxTM and Scion Image analysis of lens photographs were used to estimate cataract image blurring.
The degree of cataract blurring of the images increased with both temperature and γ-radiation dose (up to 10 Gy), while the percent differences in lens weights decreased with increasing temperature. In response to the stress, the following bands changed in intensity with increasing temperature: Hsps 70, 27 increased. With γ-radiation dose, ubiquitin decreased, and Hsps 70, 27, and Cu/ZnSOD increased. Scantox cataract grade increased linearly with proton dose up to 2 Gy, and increased after 1 Gy neutron radiation.
The lens stress responses appear to be tailored to the sort of stress the lens encounters. High energy proton and neutron irradiation appears to be more damaging than γ-radiation.
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