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Objective:To investigate the effects of hydroxysafflor yellow A (HSYA) on depressive-like behavior and expression of type A γ-aminobutyric acid receptor(GABAAR)in hippocampus of chronic restraint stress model mice.Methods:The SPF grade male C57BL/6C mice were divided into Control group, HSYA group, Model group, Model + HSYA group and Model + fluoxetine group according to random number table method, with 12 mice in each group.Mice model of depression was established by chronic restraint stress.Mice in HSYA group and Model+ HSYA group were intraperitoneally injected with HSYA(20 mg/kg), mice in Model+ fluoxetine group were injected intraperitoneally with fluoxetine (10 mg/kg), and mice in Control group and Model group administered with 0.9% sodium chloride solution intraperitoneally once a day for 14 days.Then, the forced swimming test (FST) and tail suspension test (TST) were performed to evaluate the depressive-like behavior of mice, and the protein expression levels of different subtypes of GABAAR in the hippocampus of mice were determined by Western blot.SPSS 19.0 and GraphPad Prism 8.0 software were used for data statistical analysis and mapping.One-way ANOVA was used for comparison among groups, and Tukey-HSD test was used for further pairwise comparison.Results:(1) In the behavioral tests, there were significant differences in swimming immobility time of FST and tail suspension immobility time of TST among the five groups ( F=21.59, 20.81, both P<0.05). The swimming immobility time ((143.91±9.97) s) and tail suspension immobility time (( 107.00±6.54) s) in Model group were higher than those in Control group ((52.92±6.70) s, ( 43.50±5.96) s, both P<0.05). There were no significant difference in swimming immobility time and tail suspension immobility time between Model+ HSYA group ((26.17±7.69)s, ( 20.17±7.89)s) and Model+ fluoxetine group ((61.60±16.22)s, (34.14±10.74)s)(both P>0.05), but the swimming immobility time and tail suspension immobility time in these two groups were lower than those in Model group (both P<0.05). (2) The Western blot results showed that there were significant differences in the expression of GABAARβ1 and GABAARβ2 protein in hippocampus among the four groups ( F=12.21, 11.40, both P<0.05). The expression levels of GABAARβ1(45.60±10.76) and GABAARβ2 (46.27±4.82) protein in hippocampus of Model group were lower than those in Control group ((100.00±3.44), (100.00±3.26), both P<0.05). Compared to Model group, the expression of GABAARβ1 (79.91±5.00) and GABAARβ2 (79.08±5.53) protein in hippocampus of Model+ HSYA group were higher (both P<0.05). In addition, the expression of GABAARα1 and GABAARγ1 proteins in hippocampus were not significantly different among the four groups( F=0.23, 0.10, both P>0.05). Conclusion:HSYA can effectively alleviate depressive-like behavior in depression model mice, which may be related with the upregulation of GABAARβ1 and GABAARβ2 of hippocampus tissue.
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【Objective】 To explore the expression and role of stimulator of interferon gene (STING)-TANK-binding kinase 1 (TBK1)-interferon regulatory factor 3 (IRF3) signaling pathway in the brain of chronic stress mice. 【Methods】 Mice were divided into control (CON) group and chronic restraint stress (RST) group. Mice in the RST group were given chronic restraint stress stimulation (6 hours per day, 14 days). After 14 days, the mRNA expressions of pro-inflammatory cytokines CCL2, CXCL10, IL-1β, IL-6, IL-10, and TNFα in the brain were detected and analyzed by qRT-PCR; protein expression of STING, TBK1, p-TBK1, IRF3, and p-IRF3 were detected and analyzed by immunofluorescence staining and Western blotting. 【Results】 Compared to the CON group, the mRNA expressions of pro-inflammatory cytokines in the RST group were significantly increased (P<0.05). STING and microglia marker Iba-1 were highly co-located and the expression of STING was decreased as detected by immunofluorescence staining. Moreover, the protein expressions of STING, p-TBK1, and p-IRF3 were significantly decreased (all P<0.01). 【Conclusion】 Chronic restraint stress triggers a neuroinflammatory response and the STING-TBK1-IRF3 pathway in the brain of the RST mice is significantly inhibited.
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Objective To investigate the effect of chronic restraint stress on the expression of N6-methyladenosine (m6A)and related enzymes in the hippocampus of mice. Methods Twenty C57BL/6J male mice were randomly divided into control group and chronic restraint stress (CRS) group, the model group was given for 3 weeks chronic restraint stress to establish a mouse anxiety model. Open field test and elevated plus maze test were used to detect anxiety-like behavior; Immunohistochemistry and m6A RNA methylation assay were used to detect the expression changes of mouse hippocampal m6A; Western blotting and Real-time PCR were used to analyze hippocampal m6A related enzymes expression. Results 1.The behavioral results showed that, compared with the control group, the CRS group showed significantly reduced time spent in the center of the open field(P<0.01), the CRS group showed significantly reduced exploration time in the open arm of elevated plus maze (P<0.0001); 2. Immunohistochemical results showed that, compared with the control group, the hippocampal m6A content in the CRS group reduced significantly (P < 0.001); The results of the m6A RNA methylation assay showed that, compared with the control group, the CRS group showed significantly reduced amount of hippocampal m6A(P<0.05); 3. Real-time PCR results showed that the expression of hippocampal demethylase anaplastic lymphoma kinase B(AlkB) homolog 5(ALKBH5) (P<0.001) and fat mass and obestity associated protein(FTO) (P< 0.05) in the CRS group significantly up-regulated, the expression of methylase Wilms' tumour 1-associating protein (WTAP) (P<0.05) was significantly down-regulated compared with the control group; The expression of m6A methylation binding protein YTH domaincontaining family protein 3 (YTHDF3) (P < 0.05) and YTH domaincontaining protein 2 (YTHDC2) (P < 0.01) was significantly up-regulated. Western blotting result showed that, compared with the control group, the mouse hippocampal demethylase ALKBH5 (P < 0.05) and FTO (P < 0.05) expression in the CRS group significantly up-regulated, the expression of WTAP (P<0.01) was significantly down-regulated; m6A methylation binding protein YTHDF3 (P<0.01) and YTHDC2 (P<0.05) were significantly up-regulated. Conclusion In the anxiety model induced by chronic restraint stress, the expression of m6A in the hippocampus of mice is down-regulated. The mechanism may be related to the up-regulation of the m6A demethylase ALKBH5 and FTO or the down-regulation of the methylase WTAP.
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OBJECTIVES@#To explore the damage effects of chronic restraint stress (CRS) on amygdala cells through the rat CRS model.@*METHODS@#The rat CRS model was established, and the changes in body weight and adrenal mass in control group and CRS group were monitored at 1 d, 7 d, 14 d and 21 d. The behavior changes were evaluated by the percentage of retention time of open arms and open arm entries using the elevated plus maze (EPM). ELISA was used to detect the concentrations of rat's corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol. The changes of expression of glucocorticoid receptor (GR) and glial fibrillary acidic protein (GFAP) in amygdala were determined by immunohistochemistry and Western blotting. Ultrastructure changes of glial cell were observed by transmission electron microscopy. The apoptosis rate of amygdala was measured by flow cytometry.@*RESULTS@#Compared with the control group at the same time points, body weight of CRS 1 d, 7 d, 14 d and 21 d groups increased slowly, but adrenal mass increased significantly; the serum level of CRH, cortisol and ACTH increased significantly at 7 d, 14 d and 21 d respectively; the expression of GR in amygdala was increased while that of GFAP was decreased; EPM test suggested that the percentage of retention time of open arms and open arm entries decreased significantly after 14 d. The CRS group showed different degrees of glial cell damage in amygdala, and the apoptosis rate of glial cell was significantly increased in 21 d group.@*CONCLUSIONS@#This study successfully established a CRS model in rats, and anxiety-like behavioral changes in model rats may be caused by apoptosis of amygdala astrocytes.
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Rats , Animals , Hydrocortisone/pharmacology , Amygdala/metabolism , Adrenocorticotropic Hormone/pharmacology , Apoptosis , Body WeightABSTRACT
Objective:To explore the effects of Shenwei Ningyu pills （SNP）， a new Chinese medicine for depression， on the immunoinflammatory response mediated by Toll-like receptor 4 （TLR4）/myeloid differentiation factor 88 （MyD88） signaling pathway in the hippocampus of rats exposed to chronic restraint stress （CRS）. Method:Forty-four male Sprague Dawley rats were randomly enrolled into a normal group， a model group， an escitalopram group， and an SNP group. Except for the rats in the normal group， all rats were exposed to CRS and isolated rearing for 21 days continuously. Rats in the escitalopram group and the SNP group were administered with escitalopram （30 mg·kg<sup>-1</sup>） and SNP （18 mg·kg<sup>-1</sup>） one hour prior to CRS， respectively. The changes in body weight， sucrose preference index， horizontal movement scores， and vertical movement scores were observed by body weight assessment， sucrose preference test， and open field test. The expression of hippocampal TLR4 and MyD88 was detected by Western blot. The content of serum interleukin-1<italic>β</italic> （IL-1<italic>β</italic>）， IL-10， and tumor necrosis factor-<italic>α</italic> （TNF-<italic>α</italic>） was detected by enzyme-linked immunosorbent assay （ELISA）. Result:The results of the behavioral assessment showed that there was no significant difference in the changes of behavioral baselines among the groups before intervention. However， significant differences were found among the groups following different interventions. The body weight， sugar preference index， horizontal movement score， and vertical movement score of rats in the model group decreased after CRS for 21 days as compared with those in the normal group （<italic>P</italic><0.01）. The above indicators in the SNP<italic> </italic>group and the escitalopram group were higher than those in the model group （<italic>P</italic><0.01）， which indicated that SNP<italic> </italic>exerted an obvious antidepressant effect. The results of Western blot and ELISA showed that compared with the normal group， the model group showed elevated levels of hippocampal TLR4 and MyD88 and serum IL-1<italic>β</italic> and TNF-<italic>α </italic>（<italic>P</italic>˂0.01） and dwindled serum IL-10 （<italic>P</italic>˂0.01）， while SNP<italic> </italic>and escitalopram reversed the conditions in the model group （<italic>P</italic>˂0.01） except for TNF-<italic>α</italic>. Conclusion:The present study indicated that the antidepressant effect of SNP was presumedly achieved by inhibiting the immunoinflammatory response mediated by the TLR4/Myd88 signaling pathway in CRS rats.
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The depressant-like effects of albiflorin (AF) were studied on stressed chronic restraint stress (CRS) rats. Experimental rats were subjected to immobilization stress for a daily 6 h-restraining in a plastic restrainer for continuous 21 d and were treated with 30 or 15 mg·kg
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Objective To investigate the expression of NADPH oxidase Nox-4 induced by stress in gastric mucosa and its role in inflammation.Methods Twenty male SPF Kunming mice were randomly divided into chronic restraint stress group(stress group) and control group.Stress mice were restrained in selfmade restraint device for 2 hours each day.The rest of the time,the mice in the two groups had free access to food and water normally,experiment lasted 14 days.The histopathological changes of gastric mucosa were assessed by HE staining under light microscope.The expression of Nox-4 in gastric mucosa of mice was carried out by immunohistochemical method.The relative expression levels of Nox-4,antioxidant protein (Mn-SOD,GSH,Catalase) and inflammatory factors(IL-8,IL-1β,TNF-α) in gastric mucosa were detected by real-time quantitative RT-PCR and ELISA.Results Basal cell proliferation,neutrophil,eosinophil and plasma cell infiltration and inflammatory changes were observed in the lamina propria and glandular epithelium of stress mice,while no obvious abnormalities were found in control mice.The expression of Nox-4 in stress group was deeper and more abundant than that in control group,mainly expressed in lamina propria and glandular epithelium.The mRNA expression levels of Nox-4 in gastric mucosa of stress group was(2.42±0.51) times higher than that of control group,and blood concentration of stress group was(2.23±0.67) times higher than that of control group(t=-46.32,P＜0.001).The RT-PCR of antioxidant proteins in gastric mucosa showed that the transcription levels of Mn SOD,GSH and Catalase in stress group were significantly lower than that of control group (Mn-SOD:0.59± 0.10,GSH:0.58± 0.11,Catalase:0.57± 0.09),and there were significant differences between the two groups(t=13.57,11.67,15.01,P＜0.01).RT-PCR results showed that the transcription levels of IL-8,IL-1β,TNF-α in stress group were significantly higher than those in control group (IL-8:1.47±0.34,IL-1β:1.48 ± 0.42,TNF-α:1.51 ± 0.37),and there were significant differences in two groups(t=-18.45,-19.14,-20.85,P＜0.01).ELISA results showed that the serum levels of inflammatory factors in stress group were significantly higher than those in control group(2.25±0.37,3.59±0.45,3.41±0.34),and the differences were statistically significant(t=-47.11,-79.36,-96.32,P＜0.01).Pearson correlation analysis showed that there was a positive correlation between serum concentration of Nox-4 and inflammatory factors(IL-8,IL-1β,TNF-αt) in stress group(r=0.97,0.99,0.98,P＜0.01).Spearman rank correlation analysis showed that the grade of gastric mucosal inflammation was positively correted with serum levels of Nox-4 and inflammatory factors (IL-8,IL-1β,TNF-α) (r =0.96,0.92,0.91,0.94,all P＜ 0.01)Conclusion Stress may lead to gastric mucosal lesion by overexpression of proinflammatory factors through destroying the balance of oxidation/antioxidant system in gastric mucosa.
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Objective: To investigate the role of anterior part of commissural subnucleus of nucleus tractus solitarius (acNTS) injury in insulin-resistant hyperglycemia during chronic restraint stress (CRS). Methods: We produced the CRS models (n = 20, a 7-day restraint followed by a 3-day free moving procedure for 40 days) in rats, and detected the parameters related to glucose metabolism. Results: The CRS induced a moderate (not higher than 11 mmol/L) and irreversible insulin-resistant hyperglycemia in about 1/3 (n = 7) of the individuals. CRS-hyperglycemic rats showed a condensed staining of acNTS neurons, and Caspase-3 immunostaining and TUNEL also showed positive, indicating apoptotic changes of acNTS neurons. After acNTS mechanical damage (n= 6), the blood glucose level rised gradually, which also led to insulin-resistant hyperglycemia. The characteristics of hyperinsulinemia, increased islet volume, and serum corticosterone levels in acNTS mice were consistent with those of CRS mice. Conclusion: The result indicates that during CRS, injury (apoptosis) of glucose-sensitive acNTS neurons causes dysregulation of blood glucose. Restraint stress model has value as a potential application in the study of stress-induced hyperglycemia.
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OBJECTIVE: To observe the effect of acupuncture on the expression of glial fibrillary acidic protein (GFAP) in hippocampus and prefrontal cortex and the level of serum interleukin 10 (IL-10) in rats with depression, so as to explore its mechanism underlying improvement of depression. METHODS: Thirty-two male SD rats were randomly divided into four groups: control, model, acupuncture, and medication (Fluoxetine, Flu) (n=8 rats in each). The depression model was established by using chronic restraint stress (constraint, fasting, water deprivation, etc.) combined with solitary raising for 28 days. Acupuncture was applied to "Baihui" (GV 20) and "Yintang" (GV 29), and bilateral "Sanyinjiao" (SP 6) for 20 min, once daily for 28 days. Fluoxetine (1.8 mg/kg) was given to rats of the medication group by gavage once every day for 28 days. Sucrose consumption test and open field test (crossing and rearing locomotion) were carried out to evaluate the behavioral changes. Western blot was used to detect the expression of GFAP in the hippocampus and prefrontal cortex, and the content of serum IL-10 was detected by enzyme linked immunosorbent assay (ELISA). RESULTS: After modeling, the sucrose consumption, the crossing numbers and rearing times, hippocampal GFAP protein expression and serum IL-10 content were significantly decreased and prefrontal GFAP protein expression was up-regulated markedly in the model group relevant to the control group (P0.05) and in down-regulating prefrontal GFAP protein expression (P>0.05 ) except up-regulation of IL-10 level. CONCLUSION: Acupuncture intervention plays a positive role in anti-depression in rats, which may be related to its effects in regulating the expression of GFAP in the hippocampal and prefrontal astrocytes, and in increasing the content of serum anti-inflammatory cytokine IL-10.
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Objective: To explore the effects of chronic restraint stress (CRS) on the abilities of spatial learning and memory and the levels of excitatory amino acids in the hippocampal dentate gyrus (DG) in the old rats, and to investigate the neurochemical mechanism of CRS in affecting the spatial learning and memory abilities. Methods: Sixteen male SD rats (18 months old) were randomly divided into control group (n=8) and CRS group (n=8), and the rats in CRS group received CRS 2 h every day for 30 d. And then the spatial learning and memory abilities of rats were measured by Morris water maze (MWM) test, and the extracellular levels of excitatory amino acids including asparate (Asp) and glutamate (Glu) in the DG were simultaneously determined by in vivo microdialysis and HPLC. The levels of corticosterone (CORT) and epinephrine (EPI) in serum of the rats were examined by ELISA assay. Results: In CRS group, the escape latencies on the 2nd-4th days were significantly increased and the percentage of time spent in target quadrant on the 5th day was markedly decreased in MWM test compared with control group (P0. 05). Compared with control group, the levels of CORT and EPI in the serum of the rats in CRS group were significantly increased (P<0. 05). Conclusion: CRS impairs the spatial learning and memory abilities in the old rats, which may be related to the decrease of Asp level in the hippicampal DG of the rats.
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Objective:To explore the effects of chronic restraint stress (CRS) on the abilities of spatial learning and memory and the levels of excitatory amino acids in the hippocampal dentate gyrus (DG) in the old rats,and to investigate the neurochemical mechanism of CRS in affecting the spatial learning and memory abilities.Methods:Sixteen male SD rats (18 months old) were randomly divided into control group (n =8) and CRS group (n=8),and the rats in CRS group received CRS 2 h every day for 30 d.And then the spatial learning and memory abilities of rats were measured by Morris water maze (MWM) test,and the extracellular levels of excitatory amino acids including asparate (Asp) and glutamate (Glu) in the DG were simultaneously determined by in vivo microdialysis and HPLC.The levels of corticosterone (CORT) and epinephrine (EPI) in serum of the rats wereexamined by ELISA assay.Results:In CRS group,the escape latencies on the 2nd-4th days were significantly increased and the percentage of time spent in target quadrant on the 5th day was markedly decreased in MWM test compared with control group (P＜0.05).Compared with before training,the extracelluar level of Asp in the DG in control group was significantly increased on the 2nd day in MWM test;compared with control group,the extracelluar level of Asp in the DG in CRS group was significantly decreased on the 3rd day in MWM test (P＜0.05).Compared with before training,the Glu levels in the DG in MWM test in both control and CRS groups were markedly increased (P＜0.05),but there was no significant difference between two groups (P＞0.05).Compared with control group,the levels of CORT and EPI in the serum of the rats in CRS group were significantly increased (P＜0.05).Conclusion:CRS impairs the spatial learning and memory abilities in the old rats,which may be related to the decrease of Asp level in the hippicampal DG of the rats.
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Objective: To investigate the nourishing blood and smoothing liver effects of Paeoniae Radix Alba (PRA) based on metabolomics information. Methods: The stagnation of liver qi and blood deficiency syndrome rats model was established by chronic restraint stress combined with radiation. Using LC/MS method as the core technology, the principal component analysis (PCA) and partial least squares discriminate analysis (PLS-DA) as the main data analysis methods, endogenous metabolites were screened in the model rats to study the intervention mechanism of PRA. Results: Through the impact of phosphatidylcholine, lysophosphatidylcholine, ceramide, deoxycytidine, betaine, and other 21 kinds of small molecular metabolites, PRA had a certain callback effect on the disturbance of metabolic trajectory, which can improve the state of stagnation of liver qi and blood deficiency induced by external stimulating factors (such as irradiation, restraint, and loneliness). Conclusion: The nourishing blood and smoothing liver effects of PRA may be related to the sphingolipid metabolism, glycerophospholipid metabolism, linoleic acid metabolism, and alpha-linolenic acid metabolism.
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Objective To evaluate the effects of Acorustatarinowii Schott(ATS)on chronic restraint stress mice and its possible mechanisms. Methods Chronic stressed mice underwent a repeated 8h/d constraint in a specific behavior blocker ,however ,only CSA mice received once gavages of 4.5 g/(kg · d)ATS decoction for con-secutive 28 days. Morris water maze(MWM)task was conducted for evaluating learning and memory of the mice. ELISA was used to examine the levels of plasma corticosteroid. Results ATS dramatically ameliorated cognitive impairments and decreased serum corticosteroid level in the stressed mice(P<0.01). Conclusion ATS improves cognitive deficits provoked by chronic stress in mice ,which may attribute to decreasing plasma corticosteroid levels.
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Objective To compare the biological characteristics of several different anxiety rat models established by different methods of stress at different time points and provide experimental basis for the most appropriate modeling methods .Methods 60 rats were randomly divided into normal , empty bottle stress , chronic emotional stress ( CES ) group, restraint stress for 3h, 6h, and modeling respectively .In the experimental 7 d, 14 d, 21 d, elevated plus maze and fear condition system was used to test anxiety-like behavior in rats , open field test to study anxiety or depression-like behavior , forced swimming test was used to detect depression-like behavior in rats , and using the Elisa test kit to detect the contents of 5-HT, DA in the hippocampus in rats .Results Anxiety-like behavioral test results showed that rats in empty bottle stress, CES, 6 h restraint stress group started to have anxiety-like behavior since 14 d, then anxiety-like behavior was becoming increasingly apparent .Forced swimming test results showed that immobility time in 6 h restraint rats was significantly increased in the first 7 d(P <0.05).Meanwhile, compared with control group, hippocampal 5-HT, DA contents in empty bottle stress and CES rats increased significantly since 14 d.Conclusions Among several stress methods established anxiety model , anxiety-like behavior in 3 h restraint stress was not obvious; 6 h restraint stress exhibited a depression-like behavior in the forced swimming test might be due to prolonged stress .Empty bottle stress and CES can successfully establish the anxiety rat model , and the anxiety behavior of the rats have some differences . Corresponding model methods can be selected according to different experimental purposes .
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Mother-offspring interaction begins before birth. The foetus is particularly vulnerable to environmental insults and stress. The body responds by releasing excess of the stress hormone cortisol, which acts on glucocorticoid receptors. Hippocampus in the brain is rich in glucocorticoid receptors and therefore susceptible to stress. The stress effects are reduced when the animals are placed under a model wooden pyramid. The present study was to first explore the effects of prenatal restraint-stress on the plasma corticosterone levels and the dendritic arborisation of CA3 pyramidal neurons in the hippocampus of the offspring. Further, to test whether the pyramid environment would alter these effects, as housing under a pyramid is known to reduce the stress effects, pregnant Sprague Dawley rats were restrained for 9 h per day from gestation day 7 until parturition in a wire-mesh restrainer. Plasma corticosterone levels were found to be significantly increased. In addition, there was a significant reduction in the apical and the basal total dendritic branching points and intersections of the CA3 hippocampal pyramidal neurons. The results thus suggest that, housing in the pyramid dramatically reduces prenatal stress effects in rats.