Journal of Iranian Anatomical Sciences, 2009
Jafari Anarkooli I., Ph.D., Sankian M., Ph.D., Varasteh A.R., Ph.D., Haghir H., Ph.D.
Background: The aim of this study was to investigate effects of insulin and ascorbic acid on rate of Caspase – ۳ activity and DNA Laddering in hippocampus of STZ-induced diabetic rats.
Methods: Thirty male Wistar rats in five groups, 6 in each group: one control group (group C) and four diabetic groups [diabetic control (group D), treatment with insulin (group I), with ascorbic acid (group AA) and with insulin plus ascorbic acid (group I+AA)] were used in this study. Diabetes was induced by injection of 60 mg/kg STZ IP. After six weeks, rats in group I were treated with insulin (4-6 U/kg/day Sc.), rats in group AA treated with ascorbic acid (200 mg/kg/day, IP) and rats in group I+AA treated with equal dosage of both insulin and ascorbic acid for two weeks. Rats in group D were treated with saline and considered as the diabetic control group. Two weeks after treatment, animals were anesthetized and hippocampus was dissected from hemispheres. Caspase-3 activity was assessed by Fluorometry, and finally, DNA fragmentation due to apoptosis was determined by DNA laddering Assay.
Results: Caspase-3 activity in group D significantly increased compared to group C (6.7 fold), whereas it decreased after treatment with insulin, ascorbic acid or both (2.6, 4.2 and 5.1 fold, respectively). DNA laddering was observed in group D, but not in three treated groups.
Conclusion: From this survey it was concluded that treatment of STZ-induced diabetic rats with insulin and/or L-ascorbic acid could possibly inhibit apoptosis in hippocampal tissues using decrease of Caspase -3 activity and prevention of DNA Laddering.
Keywords: Diabetes, Apoptosis, Ascorbic acid, Insulin, Hippocampus