Preventive Effect of Garlic on Blood Glucose Levels and Histopathology of Pancreas in Streptozotocin-induced Diabetes in Rats

Introduction: The antidiabetic effects of garlic juice on blood glucose levels and pancreas tissue was evaluated in STZ-induced diabetes in rats. Methods: 40 male rats were divided into 5 groups of 8 as follows; 1) Normal group (N); 2) Normal + Garlic group (N+G): received 1 ml garlic juice/100g BW/day for 6 weeks; 3) Diabetic group (D): were injected with streptozotocin (60 mg/kg BW, i.p.); 4) Diabetic + Garlic-before group (D+Gb): received garlic juice for 6 weeks and were injected with STZ at the end of the third week; 5) Diabetic + Garlic-after group (D+Ga): received garlic juice for 3 weeks, after being injected with STZ. At the end of the experiment, serial sections of pancreas were prepared and stained with H&E for light microscopic investigations. Results: Serum glucose levels were significantly increased (p<0.0001) in D group in comparison with other groups. There was no significant difference between D+Gb group and N and N+G groups. Body, pancreas, and relative weights were significantly decreased (p<0.05) in D group in comparison with other groups. In D+Gb and D+Ga groups pancreas weight showed no significant difference with the normal group. In D group a decrease of pancreatic islet numbers and their mean diameter, as well as atrophy and vacuolation of pancreatic islets parenchyma were detected. These abnormal histological signs were dramatically decreased in D+Gb group compared to D group. Also in D+Ga group, considerable effects of garlic juice on the histopathological changes of the pancreas were noted, but these effects were not as dramatic as in the D+Gb group. Conclusion: Based on these results, it is suggested that garlic juice has favorable effects in preventing changes in blood glucose levels, body and pancreas weights, and the histopathological changes of pancreas in STZ-induced diabetes.