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J. R. Trevithick, T. D. Dzialoszynski, E. G. Noble; Modeling Space Radiation Cataract Risk Reduction by Antioxidants and Ontario Ginseng Extract. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1189.
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© ARVO (1962-2015); The Authors (2016-present)
Using a model in vitro lens incubation system to investigate the possible reduction of cataract risk for astronauts, jet crews and radiation accident workers by dietary agents and formulations containing antioxidants and Ontario ginseng.
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 further testing. Incubation media containing MTCA (a glutathione precursor, (2(RS)-methylthiazolidine-4-®-carboxylic acid. 1 µM) or two mixtures beta-carotene ( 1 µM), ascorbate (1 µM), and either pycnogenol ( 5 mg/ml), BCP, or a dried alcoholic extract of Ontario ginseng (BCG, 5 mg/ml) were tested. Lenses were exposed to radiation stress by exposure to 74 MeV protons, or a neutron spectrum similar to the atmospheric spectrum of neutrons from 1- 400 MeV . Each day photos of the lens trays placed on graph paper, and protein leakage in the medium was determined by a Bradford assay. After post-stress incubation for 24 hr. or up to 7 days, 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 at the termination of the incubation and Scion Image analysis of daily lens photographs were used to estimate cataract image blurring.
BCP decreased the cataract grade determined by ScantoxTM 24 hr after radiation with protons or neutrons , while BCG increased the cataract grade at doses of 1 and 2 Gy proton irradiation. MTCA -treated lenses showed elevated protein leakage into the medium after both 24 hr and 5 days of incubation following proton irradiation and slightly higher leakage after neutron irradiation. Hsp70 after 7 days incubation was decreased by BCP at higher proton doses, as were Hsp27 and nonphosphorylated Hsp27 after 24 hr.
Mixtures of antioxidant food factors appear to be promising in reducing risk of cataract following exposure of eye lenses to high energy protons or neutrons. Addition of ginseng to the antioxidants may lead to increased risk at low doses (1-2 Gy) of proton irradiation. Heat shock proteins appeared to be lower in concentration in irradiated lenses if they were treated with BCP.
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