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Changes in expression profiles of antioxidant enzymes in diabetic rat kidneys
Gökhan Sadi1, Nihan Eryilmaz, Egemen Tütüncüoğlu
1Department of Biology, Karamanoğlu Mehmetbey University, Karaman, Turkey. sadi@kmu.edu.tr
Background:
In diabetes mellitus, increased formation of reactive oxygen species due to high level of glucose in both blood plasma and tissues creates oxidative stress and damages the tissues. Antioxidants together with the antioxidant enzymes are very important in order to protect the cells against oxidative damage.
Methods:
Differential expressions of both mRNA and proteins of major antioxidant enzymes in streptozotocin-induced diabetic rat kidneys were measured with the help of real-time polymerase chain reaction and western blot analysis, respectively. Furthermore, effects of two strong antioxidants α-lipoic acid, vitamin C and their combination on the regulation of both expressions and the activities of antioxidant enzymes were also studied.
Results:
In diabetic rat kidney tissue, both catalase and glutathione peroxidase activities were reduced (although mRNA expression for both was greatly increased) when compared with controls. No significant change was observed in superoxide dismutase (SOD) activity. Alpha-lipoic acid increased catalase activity towards the control values. Combined administration of alpha-lipoic acid and vitamin C increased the activities of both catalase and SOD, demonstrating a posttranslational effect. Glutathione concentrations were decreased in diabetic kidney; alpha-lipoic acid treatment partially restored the glutathione levels.
Conclusions:
All data showed the importance of post-transcriptional and translational regulation of the antioxidant enzyme activities against oxidative stress that is associated with diabetes.
Insights
Diabetes causes oxidative stress, damaging kidneys. Antioxidants like alpha-lipoic acid and vitamin C help restore antioxidant enzyme function, highlighting the importance of post-translational regulation in managing diabetes-related tissue damage.
Area of Science:
- Biochemistry
- Molecular Biology
- Endocrinology
Background:
- Diabetes mellitus is characterized by hyperglycemia, leading to increased reactive oxygen species (ROS) and oxidative stress.
- Oxidative stress in diabetes damages tissues, underscoring the critical role of antioxidants and antioxidant enzymes in cellular protection.
Purpose of the Study:
- To investigate the expression and activity of key antioxidant enzymes in the kidneys of diabetic rats.
- To evaluate the effects of alpha-lipoic acid and vitamin C on antioxidant enzyme regulation in diabetic kidney tissue.
Main Methods:
- Real-time polymerase chain reaction (PCR) and western blot analysis were used to measure mRNA and protein expression of antioxidant enzymes.
- Enzyme activities and glutathione concentrations were assessed in streptozotocin-induced diabetic rat kidneys.
- The impact of alpha-lipoic acid, vitamin C, and their combination on these parameters was examined.
Main Results:
- Diabetic rat kidneys showed reduced catalase and glutathione peroxidase activity despite increased mRNA expression, indicating post-transcriptional regulation.
- Superoxide dismutase (SOD) activity remained unchanged, while alpha-lipoic acid treatment improved catalase activity.
- Combined alpha-lipoic acid and vitamin C administration enhanced both catalase and SOD activities, suggesting a post-translational effect. Glutathione levels were restored by alpha-lipoic acid.
Conclusions:
- Antioxidant enzyme activity in diabetic kidneys is regulated at post-transcriptional and translational levels.
- Alpha-lipoic acid and vitamin C demonstrate potential therapeutic benefits by modulating antioxidant defense mechanisms against diabetic oxidative stress.
