Effect of diabetes on spatial memory ability in rats using Morris water maze

Abstract

Objective To study the effect of diabetes on spatial memory ability and spatial associative memory ability in rats. Methods 70 SD rats( 180±20 g) were randomly divided into 3 groups: control group,type1 diabetes group and type2 diabetes group. Type1 and type2 diabetic rat models were set up by streptozocin (STZ) intraperitoneal injection and high fat forage raise. The blood glucose was determined. After rat diabetic model established 1 month and 3 months, respectively, the Morris water maze experiments were implemented,including 4 days' place swimming and 1 day's space exploration. Results After 1 month, diabetic rats' spatial memory ability and spatial associative memory ability were not affected. After 3 months, in place swimming test,the escape latency of two diabetic rat groups was obviously longer than that of the control group (P＜0.05). From the second day of the experiment, escape latency of the control descended sharply, while that of the diabetic group descended slowly. There was no difference between type 1 and type2 diabetic groups in escape latency (P＞0.05). After 3 months, in the space exploration test, when rats were put into the maze from I quadrant which already trained, swimming time in the platform quadrant was shorter, the other parameter scores were lower of the two diabetic model groups, contrast to the control group (P＜0.05). The parameter scores of type2 diabetic group were lower slightly than type1 diabetic group. When rats were put into the maze from IV quadrant for which never trained, the parameter scores of two diabetic groups were lower than that of the control group (P＜0.05) and the total score of type 1 group was lower than that of type2 group. Conclusion The spatial memory ability and spatial associative memory ability of type 1 and type2 diabetic rats descended. In the experiment, the spatial memory ability of type2 diabetic rats was more significantly affected than that of type1 diabetic rats. By contrast,type 1 diabetic rats' spatial associative memory ability descended greatly than that of type2 diabetic rats. Key words: Type1 and type2 diabetes; Rats; Morris water maze; Spatial memory ability; Spatial associative memory ability