Oxidative defense enzyme activity and mRNA levels in lenses of diabetic rats.
This study examines the mRNA expression and enzyme activity of oxidative defense enzymes during the course of streptozotocin-induced hyperglycemic cataract development. Diabetes was produced in 5-wk-old male Sprague-Dawley rats by administering streptozotocin ip and mRNA expression and enzyme activity were monitored on d 4, 8, 12, 16, 20, 40, 60, and 80; concomitantly, the onset and progress of cataract was followed by digital image analysis. Peak enzyme activity and mRNA expression were attained between d 20 and 40. Although catalase and glutathione peroxidase maintained high levels of mRNA expression through d 60, induction of CuZu-superoxide dismutase was transient, with the activity and mRNA levels returning to baseline values by d 40. There was a pronounced increase in aldose reductase activity, which gradually declined to basal levels by d 60; however, the mRNA levels remained unaltered. Other changes included a progressive loss of lenticular transparency, which declined to 40% of control by d 80. The role of antioxidant defense enzymes and, more interestingly, aldose reductase in combating oxidative stress in diabetic cataractogenesis is discussed.
Khanna
P
P
Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston 77555-0647, USA.
Wang
L
L
Perez-Polo
R J
RJ
Ansari
N H
NH
D000449:Aldehyde Reductase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D002386:Cataract / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism*; D006943:Hyperglycemia / Q000201:enzymology; D007091:Image Processing, Computer-Assisted; D007908:Lens, Crystalline / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D000449:Aldehyde Reductase; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase