title: Alterations in antioxidant enzyme activities in the eyes, aorta and kidneys of diabetic rats relevant to the onset of oxidative stress.
abstract: Profound changes in antioxidant enzyme activities were observed in a number of vascular tissues during the development of streptozotocin-induced diabetes in rats. In the eyes, there was an increase in superoxide dismutase activity at week 4 of diabetes. However, no difference in superoxide dismutase activity was observed between the control and diabetic animals at week 8. On the other hand, the diabetic state did not seem to affect the catalase activity in the eyes. There was a generalized increase in catalase activity of the eyes from week 4 to week 8 irrespective of the diabetic state. For glutathione peroxidase in the eyes, a decreased activity was observed in the diabetic animals at week 8, but not in week 4. A different pattern of enzyme activity changes was observed in the aorta where an increase in superoxide dismutase activity was observed in the diabetic group at week 4 but not in week 8. On the other hand, an increase in catalase activity was observed only at week 8 but not at week 4. Whereas there was no observed difference between the control and diabetic animals in glutathione peroxidase activity in the aorta, except for a generalized decrease from week 4 to week 8 in both groups of animals. In big contrast to the eyes and aorta where an increase in superoxide dismutase activity was observed at week 4 of diabetes, no change in kidney superoxide dismutase activity was noted at week 4 and a decrease was observed at week 8. A similar pattern of enzyme activity changes was observed for glutathione peroxidase in the kidneys. The catalase activity in the kidneys was not affected at all by the diabetic state at both week 4 and week 8. These results clearly demonstrate the active involvement of these antioxidant enzymes during the development of diabetes, and could be rationalized by the differential response of the tissues towards the different extent of oxidative stress imposed by the diabetic state on the different tissues.
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong, China. kkmyue@hkbu.edu.hk
authors.forename: Kevin K M
authors.initials: KK
authors.lastname: Yue
authors.forename: Sze-nga
authors.initials: SN
authors.lastname: Leung
authors.forename: Po-mei
authors.initials: PM
authors.lastname: Man
authors.forename: Wing-fai
authors.initials: WF
authors.lastname: Yeung
authors.forename: Wai-shing
authors.initials: WS
authors.lastname: Chung
authors.forename: Kin-wah
authors.initials: KW
authors.lastname: Lee
authors.forename: Albert W N
authors.initials: AW
authors.lastname: Leung
authors.forename: Christopher H K
authors.initials: CH
authors.lastname: Cheng
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism*; D001786:Blood Glucose; D002374:Catalase / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology* / Q000503:physiopathology; D005123:Eye / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*; D010088:Oxidoreductases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D010088:Oxidoreductases; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase