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Lens superoxide dismutase and catalase activities in diabetic cataract
Bilgin Ozmen1, Dilek Ozmen, Esin Erkin
1Department of Internal Medicine (Endocrinology), Celal Bayar University School of Medicine, Manisa, Turkey.
Objective:
Biochemical evidence suggests that the oxidative damage of the lens proteins is involved in the genesis of senile cataract and the development of diabetes-related pathologic changes such as the formation of cataracts. In particular, lens proteins are subject to extensive oxidative modification. Oxidative damage either decreases the antioxidant capacity or decreased antioxidant capacity results in oxidative damage. The purpose of this study was to analyze the activities of the antioxidant enzymes such as Cu,Zn Superoxide Dismutase (Cu,Zn-SOD) and catalase in the cataractous lenses of the type 2 diabetic group and cataractous lenses of the senile group.
Method:
Eighteen diabetic cataractous lenses and twenty six senile cataractous lenses were studied. Cu,Zn-SOD activity was measured in lenses by enzymatic method and catalase activity was measured by colorimetric method.
Results:
Cu,Zn-SOD levels were significantly lower in the diabetic cataractous lenses than senile cataractous lenses (respectively 8.052 +/- 0.818, 18.216 +/- 4.217 microg/g prot. p < 0.05). Similarly, catalase levels were significantly lower in the diabetic cataractous lenses than senile cataractous lenses (respectively 0.326 +/- 0.134, 0.665 +/- 0.322 kU/g prot. p < 0.001).
Conclusion:
The results of the present study indicate that the antioxidant capacity in the diabetic cataractous lenses were decreased and this result suggests a role of antioxidant enzymes in the genesis of diabetic cataracts.
Insights
Diabetic cataracts show lower antioxidant enzyme activity, specifically Cu,Zn Superoxide Dismutase (Cu,Zn-SOD) and catalase, compared to senile cataracts. This suggests a role for reduced antioxidant capacity in diabetic cataract formation.
Area of Science:
- Biochemistry
- Ophthalmology
- Diabetology
Background:
- Oxidative damage to lens proteins is implicated in senile cataract and diabetes-related cataracts.
- Lens proteins undergo significant oxidative modification, linked to antioxidant capacity.
- Reduced antioxidant capacity can lead to oxidative damage, and vice versa.
Purpose of the Study:
- To investigate and compare the activities of antioxidant enzymes, Cu,Zn Superoxide Dismutase (Cu,Zn-SOD) and catalase, in cataractous lenses from type 2 diabetic patients and senile cataract patients.
Main Methods:
- Analysis of 18 diabetic cataractous lenses and 26 senile cataractous lenses.
- Quantification of Cu,Zn-SOD activity using an enzymatic method.
- Measurement of catalase activity via a colorimetric method.
Main Results:
- Diabetic cataractous lenses exhibited significantly lower Cu,Zn-SOD levels (8.052 ± 0.818 μg/g protein) compared to senile cataractous lenses (18.216 ± 4.217 μg/g protein; p < 0.05).
- Catalase levels were also significantly reduced in diabetic cataractous lenses (0.326 ± 0.134 kU/g protein) versus senile cataractous lenses (0.665 ± 0.322 kU/g protein; p < 0.001).
Conclusions:
- The findings indicate a diminished antioxidant capacity in diabetic cataractous lenses.
- This reduction in antioxidant enzymes suggests a significant role in the pathogenesis of diabetic cataracts.