Abstract: ObjectiveTo investigate the learning and memory ability of rats with obesity induced by high-fat diet. MethodsAccording to body weight,10 Sprague-Dawley(SD)rats(SPF grade)were randomly selected from 50 SD rats and were administered D-galactose subcutaneously once a day for ten weeks and fed with basal diet to establish a rat model of learning and memory impairment and a positive control group.The other 40 rats were fed with high-fat diet for 2 weeks,of which 10 control rats were selected according to their body weight and fed with basal diet,while the other 30 rats were fed with high-fat diet.Ten weeks later,another 10 obese rats were also selected according to their body weight from the 30 obese rats.Morris water maze was used to determine learning and memory ability of the rats.Serum samples were collected for serum lipid measurement. ResultsThe body weight,perirenal fat,inguinal fat,omental fat,and body fat content of obese rats were significantly higher than those in the rats of other groups.Blood lipid level in different groups showed no significant difference.The escape latency(18.54±2.73 s)and total distance(298.60±48.18 cm)in positive control group were increased compared to those in the control group(8.27±1.82 s,124.85±29.17 cm),respectively(P<0.05 for all).The escape latency and total distance in the 3rd quadrant were 9.72±2.19 s and 166.31±37.12 cm for the rats of obesity group,with a non-significant increase tendency compared to the rats of control group.In addition,the frequency of crossing the platform for the rats in different groups showed no change. ConclusionLearning ability may be impaired in rats with obesity induced by high fat diet.