Salvianolic acid improves cognitive function in rats with depression

Abstract

Objective To investigate the effect of salvianolic acid on cognitive function in rats with depression. Methods 92 SD male rats were randomly divided into 5 groups: non stress+ saline(control group, n=19), stress+ saline (saline group, n=19), stress+ fluoxetine (fluoxetine group, n=18), stress+ salvianolic acid (salvianolic acicl group, n=20) and stress+ salvianolic acid+ fluoxetine (combination group, n=16). Chronic mild stress was used to establish depression model in rats. When models were successfully established, fluoxetine 20 mg·kg-1(A), salvianolic acid 40 mg·kg-1(B), combination of A and B and 0.9% sodium chloride were given by intraperitoneal injection respectively, the volume to body weight ratio was 10 ml·kg-1. After 3 weeks of stress and drug administration, the added weight (g) and sucrose preference rate (%) were measured. The Morris water maze (MWM) test was adopted after 3 weeks' stress and 3 weeks' drugs injection to evaluate the change of cognitive function. Results After 3 weeks' stress, a significant difference was found among 5 groups(F=11.828, P<0.01) and the added weight of control group was higher than other groups(all P<0.05). There was significant difference of the mean of average escape latency among 5 groups' rats during the first 5 days of MWM(F=5.732, P<0.01), and difference was found in the measurements of the time (F=136.000, P<0.01). The average escape latency of control group was lower (all P<0.05), and the time of across the platform quadrant were longer than those of other groups (all P<0.01). After 3 weeks' drug injection, the added weight in saline group was lower than that of the groups of fluoxetine, salvianolic acid and combination(all P<0.01). The sucrose preference rate in the groups of fluoxetine, salvianolic acid, and combination group was lower than that of saline group(all P<0.01). In MWM test, the difference of average avoid latency was existed in the five groups of the first 5 days (F=16.243, P<0.01). Similarly, there was a significant difference in measure time (F=9.359, P<0.01). And a significant difference was found in crossing the platform quadrant in the 6th day of MWM (F=14.499, P<0.01). Compared with saline group((9.39±2.22)s), the time crossing the platform quadrant at sixth day in the control group((16.93±4.49)s), fluoxetine group((16.89±3.99)s), salvianolic acid group((13.82±4.77)s) and combination group((18.74±4.63)s) were increased(all P<0.01). The time of crossing platform quadrant in combination group was higher than that of salvianolic acid group(P<0.05). Conclusion Salvianolic acid can improve cognitive function in depression rats. Key words: Salvianolic acid; Depression; Cognitive function; Chronic mild stress; Water maze