Abstract
Purpose: :
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
Methods: :
: 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 either an alcohol (ALC-G) or an an aqueous (AQ-G) extract of Ontario ginseng 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 on graph paper were used to estimate cataract image blurring.
Results: :
The cataract grade determined by ScantoxTM or Scion 24 hr after radiation showed protection at doses of 1 and 2 Gy neutron irradiation, which correlated with decreased induction of Hsp 27, for ALC-G. Treated lenses showed less protein leakage into the medium after 24 hr of incubation following proton irradiation particularly for ALC-G, correlated with preservation of Cu/Zn SOD activity and lower HSF-1 in ALC-G treated lenses.
Conclusions: :
Mixtures of antioxidant food factors were previously shown to be promising in reducing risk of cataract following exposure of eye lenses to high energy protons or neutrons. Ginseng by itself as an antioxidant may lead to decreased cataract risk after low doses (1-2 Gy) of neutron irradiation. Cu/Zn SOD was preserved and HSF-1 heat shock factor appeared to be lower in concentration in proton- irradiated lenses if they were treated with ALC-G.
Keywords: cataract • radiation damage: light/UV • antioxidants