The effects of salvianolic acid on depression related behavior in chronic mild stress rats

Abstract

Objective To observe the effect of salvianolic acid on the depressive behavior in rats. Methods 33 healthy male Sprague Dawley (SD) rats were divided into 5 groups, one control group with no stress challenge(n=6) and 4 chronic stress groups(saline group, n=6; fluoxetine group, n=7; salvianolic acid group, n=7; fluoxetine + salvianolic acid combination group, n=7. The rats but not in control group were exposed to stress for 3 weeks, and then were daily afternoon injected intraperitoneally saline(10 ml/kg), fluoxetine(20 mg/kg), salvianolic acid(40 mg/kg) or combined fluoxetine and salvianolic acid, with dosage of 10 ml/kg. Sucrose preference test and the weights of rats were measured every week. Open field test (OFT) and forced swimming test (FST) were performed after chronic stress challenge and drug treatment to assess the effect of drug treatments on depressive-like symptoms. One-way ANOVA and LSD methods were adopted to compare two groups (the weight (g) of rats, the last 4 minutes duration of immobility in the forced swimming test (s), sucrose preference values(%) and open field locomotor activities (the number of crossing grids, stand-up times, grooming times and feces) of the baseline, 21days after stress exposure and 21 days after drug injection). Results 21 days after stress exposure, differences were found in the body weights, sucrose preference values, the last 4 minutes duration of immobility in the forced swimming test and the locomotor activities for 5 minutes (the number of crossing grids and stand-up times) in the OFT (F were 3.747, 14.968, 8.439, 38.925, 7.893 respectively, all had P 0.05). 21days after drug were given, differences were found in the weights of 5 groups, sucrose preference values, the last 4 minutes duration of immobility in the forced swimming test as well as the number of crossing grids and stand-up times in the OFT (F were 8.179, 6.609, 27.608, 34.149, 4.341 respectively, all P 0.05). The number of stand-up times in the fluoxetine, salvianolic acid and combination groups were higher than the control and saline groups as compared in pairs (all P 0.05). Conclusion Salvianolic acid could improve the behaviors of rat with depression, and the effect of which may be comparable to fluoxetine. Key words: Depressive disorder; Fluoxetine; Disease models, animal; Behavior; Salvianolic acid; Chronic mild stress