OBJECTIVE: To study Tremella extract antidepressant activity in rats Method Male Wistar-rats (body weight 180 - 220 g) chronic stress depression model rats were randomly divided into 4 successful modeling groups, The model group (normal saline 2.0 ml/kg), the low dose group of Tremella extract ((0. 5 g / kg), the dosage group of Tremella extract (1.0 g/kg), the high dose group of Tremella extract (1 5 g/kg), blank unmodeled rats were used as a blank group, and an equal volume of normal saline was administered. Five groups of rats were administered orally for 28 days, and the time of suspension and the time of swimming were observed. And measured rat plasma and hypothalamic neurotransmitter dopamine, norepinephrine (NEB content. Results 1.5 g / kg Tremella extract can significantly increase the body weight of depressed rats (P <0.01), increase the sucrose preference of rats ( P<0.01), while 1.0-1.5 g/kg Tremella extract dose-dependently reduced the time of suspension and the time of swimming inactivity (P < 0.05), increasing rat plasma and hypothalamic dopamine (DAB) Content (P < 0.05) 1. 5 g / kg Tremella extract significantly increased the plasma and hypothalamic norepinephrine (NE) content in rats (P<0.01). Conclusion Tremella fuciformis extract has significant antidepressant activity, which may be related to the increase of rat blood prize and hypothalamic neurotransmitter content.
Key words: Tremella; chronic stress; antidepressant; norepinephrine; dopamine
Depression is a group of high-risk, high-recurrence, high-suicide, and disabling major mental disorders. The incidence of depressive symptoms in high school students in China is 25.8%, and the detection rate of depressive symptoms in college students is 20%-60. %, the prevalence rate is higher than other domestic occupational groups and foreign countries. The WHO has listed antidepressants as one of the most urgently needed drugs in the 21st century.
The etiology of depression has not yet been elucidated. It is generally accepted that the biogenic amine hypothesis, that is, the decrease in levels of biogenic amines in the neurotransmitters of the brain of depressed patients leads to depression. The clinical use of antidepressant western medicines has been developed according to this. The efficacy of these drugs is affirmative, and there are also huge side effects, and the price is high, and the drug dependence is strong. The Chinese medicines such as Morinda officinalis extract and curcumin have proved to be very good. Antidepressant activity. Tremella fuciformis, also known as white fungus and snow fungus, has been shown to have liver and anti-tumor activity, but no reports on anti-depressant activity of Tremella fuciformis have been reported.
This study established a model of diffuse stress depression in rats, demonstrated the antidepressant activity of Tremella fuciformis extract in animals, and examined whether the antidepressant activity of Tremella fuciformis is related to its enhancement of monoamine neurotransmitter secretion.
1 Materials and methods
1.1 Animal healthy adult male Wistar rats, 180 - 220 g purchased from Changchun Institute of Biological Products, laboratory animal production license number: SCXK (Liao) 2013-0003, experimental animal use license number SYXK (Ji) 2014 - 0004 During the feeding period, the rats were given standard pellet feed and pure drinking water. The feeding conditions were: room temperature 23 degrees, humidity 52%-58%, maintaining 12 h circadian rhythm (daytime of 7:00-19:00), free drinking water, experiment The pre-rats were fed adaptively for 7 days.
1.2 Experimental reagent Rat DA Elisa kit, Rat NE Elisa kit, purchased from Shanghai Yuanye Biological Reagent Co., Ltd. All other reagents were of analytical grade and purchased from Sinopharm Chemical Reagent Co., Ltd.
1.3 Instrument multi-function microplate reader, purchased from the United States Berten; constant temperature incubator, purchased from Huangshi City Medical Instrument Factory. Constant temperature water bath, purchased from Jiangsu Jintan Medical Instrument Factory; RE-52E rotary evaporator, purchased from Shanghai Yarong Company. The suspension tail experiment system was purchased from Shanghai Xinsoft Information Technology Co., Ltd. forced swimming experiment system, purchased from Shanghai Xinsoft Information Technology Co., Ltd.
1.4 Experimental methods
1.4. Preparation of crude extract of Tremella fuciformis 100 g of dried white fungus was added to deionized water at a ratio of liquid to solid ratio of 10:1 (ml/g), extracted in a water bath at 80 ° C for 3 h, cooled to room temperature, and centrifuged at 8 000 r/min. The supernatant was collected and the supernatant was collected. The extraction was repeated once. The extracts were combined and lyophilized to obtain the Tremella extract. The polysaccharide content was determined to be 14.67 % by phenol sulfuric acid method.
1.4.2 Establishment of a rat depression model A modified chronic unpredictable stress model (CUMS) was used to establish a rat model of depression. Rats in the blank group were not given any stimulation; 16 rats in each group, rats in the experimental group Single cage feeding, and 7 different chronic stressors were given to the model rats during the experimental period (8 weeks). The chronic stressors included: 124 h moist litter; forced swimming for 20 min in a 20 °C ice water bath; 3 suspension 5 min; 4 clips 1 min cis 50 0C oven baking for 5 min ; ) 24 h fasting, 12
h banned water; 7 upside down. The above stimulation is one cycle every 7d, the order is random but the same stimulus cannot be used continuously. See Table 1 for the scheme.
1.4.3 Rats grouped and administered chronic stress four weeks, the rats were randomly divided into 5 groups, respectively: blank group (Control): blank unmodeled rats, 5-8 weeks intragastric administration 2. 0 Ml/kg normal saline; model group: chronic unpredictable stress at 8 weeks, 2.0 ml/kg saline at 5-8 weeks; low dose at Tremella extract: 8 weeks chronic unpredictable stress, 5th to 8th week of intragastric administration of 0.5 g / kg of normal saline; Tremella extract dose group: 8 weeks of chronic unpredictable stress, 5-8 weeks of intragastric administration of 1.0 g / kg of normal saline; white fungus The high-dose group of extracts: chronic unpredictable stress at 8 weeks, and 1.5 g/kg of normal saline was administered intragastrically at weeks 5-8. The rats were administered with continuous intragastric administration for 28 days, and stimulation was continued during the administration. Animals were free to eat and drink during the experiment.
1.4.4 Sucrose water consumption test After the end of the administration, the rats were allowed to drink 1% sucrose solution for 3 days and then drink normal drinking water for 1 d. 2 h before the test, the rats were fed in a single cage, and the rats were fed normally. 1% sucrose solution and tap water, this process needs to maintain the positional balance of sucrose water in each test group. After 1 h, the amount of liquid consumed was measured. Sucrose water preference 1% sucrose water consumption as a percentage of total consumption.
1.4.5 After 1 hour of administration on the 27th day of the tail suspension experiment, the tail of the rat was bound with a medical tape 1 cm from the tip of the tail, and it was hung on a crossbar about 15 cm from the ground for 6 min. The immobility time within 5 min after the rat was blocked by whiteboard to avoid mutual interference.
1.4.6 For 1 hour after the 28th day of forced swimming test, the rats were placed in plastic buckets with a diameter of about 20 cm, a water depth of 17 cm and a water temperature of (2211) 0C. The experiment was observed for 6 min, and the rats were recorded within 5 min. Accumulate time.
1.4.7 Tissue collection and DA NE content determination After the end of the experiment, the rats were decapitated and blood was collected. The rat hypothalamic tissue was quickly removed and homogenized with double distilled water for determination.
1.4.8 Statistical Methods Statistical analysis was performed using SPSS statistical software. The data were expressed as (x1s) and analyzed by one-way analysis of variance (ANO-VA). Inspection level. = 0. 05 (double side).
2 results
The effect of Tremella fuciformis extract on the body weight of rats was significantly lower than that of the blank group (P<0.01). Compared with the model group, 1.5 g/kg Tremella extract can significantly increase chronic stress. Body weight of depressed rats (P <0.01), see Figure 1
2. The effect of Tremella fuciformis extract on sucrose preference in rats is shown in Figure 2. Compared with the blank group, the sucrose preference of the model group was significantly decreased (p<0.01). 1.5 g/kg Tremella extract significantly increased the syrup preference in rats (P <0.01).
2. 3 Tremella extract reduced the immobility time of rats compared with the blank group, the suspension time of the rats in the model group increased significantly within 5 min (P<0.01), 1.0, 1.5 g/kg of Tremella fuciformis extract significantly Decrease the time of suspension of the rat in 5 min (P <0.05) o
Compared with the suspension time of the rat, 1.0, 1.5 g/kg Tremella extract significantly reduced the swimming time of the rats within 5 min (P<0.01), as shown in Fig. 3.
2. 4 Tremella extract increased the levels of NE and DA in hypothalamus and plasma of rats compared with blank rats. The levels of DE and NE in hypothalamus and plasma of model rats were significantly decreased (P <0.05), 1.0, 1.5 g/ Kg Tremella extract can significantly increase the content of DA in rat hypothalamus and plasma (P<0.05). At the same time, Tremella fuciformis extract dose-dependently enhanced NE content in rat hypothalamus (P <0.01), as shown in Figure 4.
3 Discussion
A very important depression-like phenotype in chronic stress-depressed rats is a decrease in sucrose preference. In this study, compared with the blank group, the sucrose preference of the model group was significantly decreased, while the Tremella fuciformis extract significantly increased the sucrose preference of the rats in depression, and it was concluded that the 1.5 g/kg Tremella extract had antidepressant activity.
Forced swimming and tail-hanging experiments are commonly used behavioral testing methods for the screening of antidepressants. The principle is to place the animals in an inescapable environment. The animals will struggle and try to escape. After efforts can not get rid of difficulties, Intermittent immobility, manifested as "behavioural desperation" state, similar to depression, the vast majority of antidepressants can shorten the animal's immobility time. The study found that 1.0, 1.5 g / kg Tremella extract significantly increased the behavioral time of depressed rats within 5 min (P < 0.05), so it was concluded that Tremella fuciformis extract had certain anti-depressant activity.
The incidence of depression is gradually rising. It is expected to become the second largest disease after heart disease by 2020. The pathogenesis of depression is still unknown, but a large number of experimental studies have shown that monoamine neurotransmitters such as NE and DA are present. Change is closely related to depression. With the deep understanding of the pathogenesis of depression, the research and development of natural antidepressants has become a new hot spot and development trend.
In this study, a rat model of depression was established by chronic stress, and the anti-depressant activity of Tremella fuciformis extract was demonstrated in rats. The effect was directly related to the increase of DA NE content in rat plasma and hypothalamus. This study provides a scientific basis for the widespread use of Tremella as an anti-depressant health food and medicine.
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