In vitro photochemical cataract in mice lacking copper-zinc superoxide dismutase.
We here evaluate cataract formation in mice lacking the cytosolic copper-zinc superoxide dismutase (CuZn-SOD) in an in vitro model using irradiation with visible light and riboflavin as a photosensitizing agent. Isolated, cultured lenses from wild-type and CuZn-SOD-null mice were irradiated for 1.5 h by a daylight fluorescent light after preincubation with 10 microM riboflavin for 24 h. Cataract formation was evaluated daily with digital image analysis and ocular staging, and after 5 d 86Rb uptake and water contents of the lenses were determined. Basal superoxide concentrations in freshly isolated lenses from wild-type and CuZn-SOD-null mice were determined with lucigenin-derived chemiluminescense, and enzymatic activities of all three SOD isoenzymes in the murine lens were determined with a direct spectrophotometric method. The cytosolic CuZn-SOD accounts for 90% of the total SOD activity of the murine lens. CuZn-SOD-null lenses showed a doubled basal superoxide concentration, and were more prone to develop photochemical cataract in the present model with more opacification, more hydration, and less 86Rb uptake than lenses from wild-type mice. We conclude that CuZn-SOD is an important superoxide scavenger in the lens, and that it may have a protective role against cataract formation.
Behndig
A
A
Department of Clinical Science/Ophthalmology, Umeå University Hospital, Umeå, Sweden. anders_behndig@hotmail.com
Karlsson
K
K
Reaume
A G
AG
Sentman
M L
ML
Marklund
S L
SL
D000166:Acridines; D000818:Animals; D001834:Body Water; D002386:Cataract / Q000201:enzymology* / Q000209:etiology / Q000473:pathology; D007908:Lens, Crystalline / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D008027:Light; D008163:Luminescent Measurements; D051379:Mice; D018345:Mice, Knockout; D009924:Organ Culture Techniques; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000008:administration & dosage; D012256:Riboflavin / Q000008:administration & dosage; D012414:Rubidium Radioisotopes / Q000378:metabolism; D013482:Superoxide Dismutase / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D013481:Superoxides / Q000032:analysis
D000166:Acridines; D017319:Photosensitizing Agents; D012414:Rubidium Radioisotopes; D013481:Superoxides; C033472:10,10'-dimethyl-9,9'-biacridinium; D013482:Superoxide Dismutase; D012256:Riboflavin