Antioxidant parameters and lipid peroxidation in salivary glands of streptozotocin-induced diabetic rats

Background: There is evidence suggesting an unbalance between oxidant and antioxidant status associated with diabetes. Considering that salivary function is essential for the maintenance of oral and systemic health, this study was designed to examine the levels of reduced and oxidized glutathione and the activities of the antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, in salivary gland of streptozotocin-induced diabetic rats. Methods: The content of malondialdehyde was determined in the blood and in the salivary glands. The antioxidant status was investigated in the submandibular and parotid salivary glands. Results: Diabetic rats showed an increase in the content of malonaldehyde in the blood and in the submandibular salivary gland, but not in the parotid gland. Both forms, reduced and oxidized glutathione content present higher values in the diabetic submandibular gland compared with controls. No difference in the activity of superoxide dismutase between the diabetic and control glands was observed in either gland. Catalase showed higher specific activity in the parotid gland of the diabetic rats than control; however, in the submandibular gland, only when expressed as unit per gland was it higher than control. The specific activity of glutathione peroxidase was higher in the diabetic parotid gland than control, however, in the submandibular gland, its activity per gland was lower than controls. Conclusion: The streptozotocin-induced diabetes in rats caused different results comparing the submandibular and parotid salivary glands. (C) 2004 Elsevier B.V. All rights reserved.