Effects Of Polysaccharide Of Rhizoma Polygonati On Behaviors Of Mice With Chronic Stress Depression And Its Possible Mechanism

OBJECTIVETo observe the effects of PRP on behaviors,monoamine neurotransmitters(5-HT,DA,NE )and serum IL-2 contents of mice with chronic stress depression. And to discuss whether PRP has anti-depression effect and its possible mechanisms.METHODSThe mice with chronic stress depression was made by the chronic unpredictable stress and solitary custody(d1~d21). Mice were divided into six guoups and were administrated intragastrically PRP (100, 200, 400 mg·kg-1, d1~d21) and Extract of St. John's Wort (100 mg·kg-1, d1~d21) as control groups. And for the groups of normal and model group, mice were given an equal volume of vehicle (CMC-Na) at the same time.To record the weight of each mouse in the experimental section first, 21th day and comparie the weight gain of mice in each group. The changes of behaviors in mice were observed by determing autonomous activity,sugar water consumption,immobility time in tail suspension and spatial learning and memory capacity. Using the High Performance Liquid Chromatography(HPLC) to detect the monoamine neurotransmitters, and the Radioactive immunoassay(RIA) to detect serum IL-2.RESULTS1. The effects of PRP on body weight of mice with chronic stress depression. On the 21th day, the weight gain of model mice were markedly less than that of normal group, the weight gain of mice in three doses of the PRP all increased compared with model control.2. The effects of PRP on behaviors of mice with chronic stress depression(1) The number of autonomic activities of model mice decreased significantly compared with normal control, while that of PRP groups all increased. (2) The immobility time in tail suspension of model mice were obviously longer than that of normal group, and PRP groups all increased. (3) The consumption of sugar water of model mice less than normal group, while that of PRP groups raised. (4) In the water maze test, the escape latent period of model mice were longer than normal group on the fourth day, the explore time of original platform area of model mice were significantly shorter than normal group. The three doses of PRP could shorten the escape latent period and prolong the explore time of original platform area of mice with chronic stress depression. 3. The effects of PRP on monoamine neuro-transmitters of mice with chronic stress depressionThe monoamine neurotransmitters(5-HT, DA, NE ) contents in model mice were significantly[0] less than normal group. PRP(100, 200, 400 mg·kg-1)could heighten the contents of 5-HT,DA of mice with chronic stress depression; and the NE level of mice in PRP(100, 200, 400 mg·kg-1)group approached a rising trend , but no statistical significance.4. The effects of PRP on the serum levels of IL-2 of mice with chronic stress depressionThe serum levels of IL-2 in model mice were markedly more than normal group, PRP(200, 400 mg·kg-1)could reduce the IL-2 serum contents of mice with chronic stress depression.CONCLUSIONS1. The PRP could improve behaviors of mice with chronic stress depression. It suggested that PRP may prevent and improve depressive symptoms.2. The PRP could heighten the level of monoamine neurotransmitters(5-HT, DA) in the brain and reduce the contents of IL-2 in serum, that maybe the possible mechanisms of the anti-depression of the PRP.