Failure to detect the anti-mutagenic effect of insulin in experimental type-2 diabetic rats

Abstract

Background: The oxidative stress is known to cause mutation-related disorders
in diabetic patients. Materials and Methods: The present study was designed to
investigate the anti-mutagenic effect of insulin in nicotinamide (NA: 230 mg/kg,
i.p.) and streptozotocin (STZ: 65 mg/kg, i.p.) induced nuclear defects. Bone marrow
micronucleus (MN) test and caudal epididymal sperm abnormalities were detected to
find the somatic and germinal cell mutations, respectively. The antioxidant status was
determined by estimating serum lipid peroxidation, catalase, superoxide dismutase and
glutathione peroxidase levels. Results: The experimental type diabetes significantly
(P < 0.001) reduced the antioxidant status and enhanced MN frequency and sperm
defects compared to control animals. Although administration of insulin (1, 3, 5 and
7 IU/kg, s.c. for 4 weeks) significantly (P < 0.001) reduced hyperglycemia, it did
not alter the antioxidant status, and somatic and germinal cell defects in diabetic rats.
Conclusion: The results suggest that insulin did not have protective effect against
the genotoxicity induced by NA-STZ diabetes.