Intervention Effect And Mechanism Of Sini Powder On Acute And Chronic Psychological Stress

ObjectiveIn modern society, humans are plagued by complex psychophysiogical disorders, which are triggered or influenced by social psychological factors. Stress theory is used to elucidate the relationship between psychological factors and diseases in modern medicine. Stress is a series of biological reactions in body after exposure to stressor. Organism has the ability to recover after exposure to stressors which are swift, tender and controllable; however, if the stressor is out of control or lasts too long, it will cause pathological changes. Among numerous biological changes related to stress, glucocorticoid (GC) as well as its recptors, glucocorticoid receptor (GR) and mineralocorticoid receptors (MR) play a key role, mediating the start and the end of reaction. In addition, the levels of monoamine neurotransmitters are very important. The psychological stress has been confirmed to play an important role in psychophysiogical disorders, also be one of the pathological processes. Hence, researchers start to look for the method targeting on the common cause, psychological stress, in addition to symptomatic treatment."Qingzhi" is the name of mood in Traditional Chinese Medicine (TCM). It summarizes the physical and psychological changes after the organism exposing to stressors. Qingzhi theory, which has a long history, is one of the most characteristic systems in TCM. There’re complete understanding and effective treatment method to Qingzhi diseases. Liver is regarded as the chief location of Qingzhi disease and dispersing liver depression as the major treating principle. Sini Powder (SP) which was documented in "Treatise on Febrile Diseases" is the typical formula of dispersing liver depression. Tremendous clinical researches report that SP is used to treat a wide range of psychophysiogical disorders. It suggests that SP may act as an anti-stress medication when it effects on these diseases.Therefore, in the present study, we explored the effect of SP on psychological stress and the relevant diseases depression and anxiety, as well as the possible mechanisms.MethodsIn order to mimic the human situation of social psychological stress, we established the acute elevated platform stress model in rats. Elevated platform stress is an inescapable stress. It’s closer to human psychological situation compared with other physical stress. Then, we took tree shrew as experimental animal. Tree shrew shares more similarity to human in respect of circadian rhythm, brain structure, gene homologies, etc., thus is regarded as the closest relative of primate. Plus it’s very sensitive to stress. So it’s very suitable as stress model.Our lab and cooperative lab developed a new method to obtain the active extract of SP (SP extract). Chinese medicines are complex multi-components. At present batch-to-batch stability of TCM is always a deterring factor in achieving quality control and consistency of efficiency. Repeatability in chemical and biological activity of the drug is the basic premise for further study. Thus we used the patent SP extract which have stable preparation method and relatively clear chemical components.Hence, in this study, we explored the effect of SP extract on acute and chronic stress and possible mechanisms by acute elevated platform stress model in rats and chronic social defeat stress model in tree shrews, respectively. And we also evaluated its antidepressive-and anxiolytic-like effects.Results1. The preparation of SP extract and other methods We conducted a pilot scale preparation of SP extract according to the existing patent, and performed quality control. We established a measurement method for determining the levels of monoamines neurotransmitters in rats’ brain tissues by HPLC with electrochemical detection for further study.2. The effect of SP extract on acute elevated platform stress in rats and possible mechanisms We established the acute elevated platform stress in rats. The serum corticosterone (CORT) and plasma adrenocorticotropin (ACTH) levels of rats were elevated after exposure to the stress. A single pretreatment of SP extract (1,2, or 4g/Kg) could rescue increased serum CORT and plasma ACTH levels in a dose-dependent manner. Additionally, it could elevated the GRmRNA, glucocorticoid receptors mRNA/mineralocorticoid receptors mRNA (MR/GR) ratio and 5-HT1a receptor mRNA, which could be one of possible mechanisms of its anti-stress effect.3. The effect of SP extract on expression of GR report gene in human MCF7cell and MR in HEK293 cellWe explored the regulation effect of SP extract on GR, MR through luciferase reporter gene system. The results showed that SP extract inhibited the GRE expression induced by GR agonist dexamethasone (Dex) when used with it, which might be one of the mechanisms of the anti-stress effect.4. The effect of SP extract on chronic social defeat stress model in tree shrews and possible mechanismsWe established the chronic social defeat stress model in tree shrews. The animals were divided into 4 groups. Except for the naive group, other animals were subjected to daily social defeat stress for 5 weeks, in the last 4 weeks treated with SP extract (3.6g/Kg/d), fluoxetine (15mg/Kg/d) and vehicle respectively. The results showed that the subordinate tree shrews exhibited body weight loss and reduction in locomotor activity compared to naive group. And the urine/serum cortisol (COR) was elevated, suggesting the hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis. SP extract could reverse body weight loss to a certain extent and the increased level of urine/serum cortisol (COR). In addition, it increased hippocampus norepinephrine (NE) concentration. Nevertheless, it has little effect on locomotor activity, other brain tissues 5-hydroxytryptamine (5-HT) and its metabolites 5-hydroxyindoleacetic acid (5-HIAA).5. The antidepressive- and anxiolytic-like effects of SP extractWe explored the antidepressive- and anxiolytic-like effects of SP extract by forced swimming test, open field test in rats and light-dark box test in mice. The results showed SP extract had antidepressive- and anxiolytic-like effects in dose-dependent manner.ConclusionTherefore, SP extract can both mediate chronic and acute stress, which is the basis of its dispersing-liver-depression effect. And this effect is regulated through GR, MR,5-HT1aR as well as NE. These also could be regarded as one of the mechanisms of its antidepressive- and anxiolytic-like effects.