The effect of Nigella sativa on learning and memory in male diabetic rats

  Abstract   Introduction: Diabetes mellitus accompanies with disturbances in learning, memory, and cognitive skills in the human society and experimental animals. Considering the beneficial antidiabetic potential of Nigella sativum (NS ), this research study was conducted to evaluate the effect of chronic consumption of NS on learning and memory in diabetic rats using passive avoidance and Y-maze tests. Methods: Male Wistar rats were randomly divided into control, NS-treated control, diabetic, and NS-treated diabetic groups. NS treatment continued for 1 month. For induction of diabetes, streptozotocin was injected i.p. at a single dose of 60 mg/kg. For evaluation of learning and memory, initial latency (IL) and step-through latency (STL) were determined at the end of study using passive avoidance test. Meanwhile, alternation behavior percentage was determined using Y maze. Results: There was a significant increase (p<0.05) in IL in diabetic and NS-treated diabetic groups after 4 weeks as compared to control group. In this respect, there was no significant difference between diabetic and NS-treated diabetic groups. On the other hand, STL significantly decreased (p<0.05) in diabetic group and significantly increased (p<0.01) in NS-treated diabetic group as compared to control group at the end of study. In addition, results of Y-maze test showed that there is a significant difference between diabetic and NS-treated diabetic groups (p<0.05) regarding alternation behavior. Discussion: In summary, chronic oral administration of NS could enhance the consolidation and recall capability of stored information and spatial memory in diabetic animals.