Antioxidant enzyme activities in IDD-prone and IDD-resistant mice: a comparative study

Area of Science:

• Immunology
• Endocrinology
• Biochemistry

Background:

• Insulin-dependent diabetes (IDD) in nonobese diabetic (NOD) mice involves autoimmune destruction of pancreatic beta cells.
• Diabetes incidence in NOD mice is sex-dependent, with females developing it more frequently than males.
• Free oxygen radicals from inflammation are a potential mechanism for beta cell destruction.

Purpose of the Study:

• To investigate if antioxidant enzyme deficiency contributes to diabetes susceptibility in NOD mice.
• To compare antioxidant enzyme activities in NOD mice with other mouse strains.
• To determine the role of antioxidant enzymes in the sex-dependent diabetes incidence in NOD mice.

Main Methods:

• Compared activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase.
• Analyzed enzyme activities in isolated islets, pancreas, and other tissues.
• Used age- and sex-matched NOD, BALB/c, C57BL/10, and B10.GD mice.

Main Results:

• Female NOD mice showed no significant difference in antioxidant enzyme activity compared to other strains.
• Antioxidant enzyme activity was generally lower in females than in males across all strains.
• Islets of NOD mice were not more deficient in antioxidant enzymes than those of BALB/c mice.

Conclusions:

• Antioxidant enzyme deficiency is unlikely to be the sole or direct cause of free oxygen radical toxicity in NOD mouse beta cells.
• The higher incidence of diabetes in female NOD mice is not explained by lower antioxidant enzyme activity.
• Higher inherent antioxidant enzyme activity in males may contribute to the lower diabetes incidence observed in male NOD mice.