Effect of Cynara scolymus Feeding on Learning and Memory Status of Diabetic Rats

Chronic diabetes mellitus via various pathways including augmented oxidative stress accompanies disturbances in learning, memory, and cognitive skills in humans and experimental animals. Due to the presence of some evidence for anti-diabetic and antioxidant activity of Cynara scolymus (CS), this study was conducted to evaluate the effect of chronic oral administration of CS on learning and memory status of diabetic rats. Female Wistar rats were divided into control, CS-treated control, diabetic, and CS-treated diabetic groups. Treatment groups received rat chow containing CS with no restriction for 6 weeks. For induction of diabetes, streptozotocin was injected intraperitoneally at a single dose of 60mg/kg. For evaluation of learning and memory, initial (IL) and step-through latencies (STL) were determined at the end of study using passive avoidance test and alternation behavior percentage was obtained using Y maze. There was no significant change in IL in diabetic and treated-control and -diabetic rats as compared to control group. Meanwhile, STL significantly decreased in diabetic (p<0.01) and CS-treated control (p<0.05) groups, while it was non-significantly reduced in treated-diabetic group. In addition, alternation behavior percentage was significantly lower in diabetic and treated-diabetic groups when compared with controls (p<0.01 and p<0.05, respectively), but it was non-significantly higher in treated-diabetic group as compared with diabetics. Although CS treatment could enhance the capability of consolidation and recall in diabetic animals, but it could not improve spatial memory in diabetic animals using Y maze. Other spatial memory tests using radial arm and Morris water mazes are recommended in future research studies.