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Objective To study the effect of dexmedetomidine (DEX), an α2- adrenoceptor agonist, on the pain-related anxiety-like and depression-like behaviour induced by complete Freund' s adjuvant (CFA) injection and its possible regulatory mechanism. Methods Thirty-six ICR female mice were randomly divided into normal saline (NS) group, CFA group and DEX + CFA group, n = 12 for each group. Chronic inflammatory pain model was established by subcutaneous injection of 10 μl CFA into the right hind limb of mice. DEX + CFA group mice were injected intraperitoneally with 0.025 mg/kg DEX 30 minutes before nociceptive behavior test, and once a day for 7 days. Von-frey fiber was used to evaluate the threshold of mechanical pain in mice, n = 12 for each group. The anxiety-like behavior of mice were detected by open field test, n = 12 for each group. Sucrose preference, tail suspension test and forced swimming test were used to detected the depression-like behavior of mice, n = 12 for each group. The expression of adrenergic receptor β2 (ADRB2), Brain-derived neurotrophic factor (BDNF), tyrosine kinase B receptor (TrkB), and glutamate receptors 1 (GluR1) and GluR2 were detected by Western blotting, n = 8 for each group. Immunohistochemical staining was used to detect the expression of recombinant doublecortin(DCX), which is a marker of newborn neurons in the hippocampus, n = 4 for each group. Results Compared with the NS group, the mechanical threshold of mice on the 1st, 3rd and 7th day after CFA injection decreased significantly (P 0.05). Compared with the NS group, the time spent in the inner ares (P<0.01), number of entering the central grid area (P<0.01) and distance travelled in the inner area (P<0.01) of CFA group mice reduced significantly, while the time (P<0.01), numbers (P < 0.05) and distance (P < 0.05) of DEX + CFA group mice entering the central grid area enhanced significantly. The result of depression-like behavior tests showed that the sucrose preference percentage (P < 0.05) reduced significantly in CFA group when compared with NS group, and the immobility time increased significantly in tail suspension test (P<0.01) and forced swimming test (P< 0.001) in CFA mice when compared with NS group, while DEX intervention could significantly increase the sucrose preference scores (P<0.05) and decreased the immobility time in tail suspension test (P<0.05) and forced swimming test (P<0.05). The result of Western blotting showed that compared with the NS group, the levels of ADRB2 (P<0.0010), BDNF (P < 0.001), TrkB (P < 0.01), GluR1 (P < 0.001) and GluR2 (P < 0.001) in the hippocampus of CFA group were significantly decreased, while DEX intervention could significantly increase the expression of ADRB2 (P<0.05), BDNF (P < 0.001), TrkB (P < 0.001), GluR1 (P < 0.001) and GluR2 (P < 0.001). Immunohistochemical result showed that compared with the NS group, the average absorbance (AA) of DCX decreased significantly in hippocampus of CFA group (P<0.05), but increased significantly in DEX+CFA group (P < 0.05). Conclusion Dexmedetomidine may promote hippocampal neurogenesis through upregulated the expression of BDNF-TrkB, thus improving CFA-induced anxiety-like and depression-like behaviors in mice.
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Background Chronic low-level exposure to lead can damage the central nervous system and cause anxiety-like behavior. However, whether changes of blood metabolites occur in this process and its relationship with lead-induced neurobehavioral disorder remain unclear. Objective To explore the effects of chronic lead acetate (PbAc) exposure at different concentrations on anxiety-like behavior and serum metabolites and their relationships in mice, as well as the mechanism of lead exposure on neurobehavioral injury in mice from the perspective of metabolomics. Methods A total of 64 healthy 4-week-old C57BL/6J mice, half male and half female, were randomly divided into four groups: control group (normal drinking water), 20 mg·L−1 PbAc group, 100 mg·L−1 PbAc group, and 500 mg·L−1 PbAc group. After 10 weeks of free drinking of water containing designed concentrations of PbAc, the mice were tested for anxiety-like behavioral changes by open field experiment. After the mice were anesthetized, blood was collected from the eyes, the serum was separated, and the effects of designed doses of lead exposure on metabolites in the serum of mice were compared by liquid chromatography with tandem mass spectrometry combined with principal component analysis and partial least squares discrimination analysis. Results The results of the open field experiment showed that the reductions in movement time spent in central area in the 100 mg·L−1 and 500 mg·L−1 PbAc groups compared with the control group were of statistical significance (P<0.05); the reduction in crossing times of central region in the 500 mg·L−1 PbAc group was statistically significant compared with the control group (P<0.05); the increases in defecation frequency in the 100 mg·L−1 and 500 mg·L−1 PbAc groups were statistically significant compared to the control group (P<0.05). In both positive and negative ion modes, compared with the control group, 157 differential metabolites were screened out in the 20 mg·L−1 PbAc group, of which 80 were up-regulated and 77 were down-regulated; 172 differential metabolites were screened out in the 100 mg·L−1 PbAc group, of which 57 were up-regulated and 115 were down-regulated; 119 differential metabolites were screened out in the 500 mg·L−1 PbAc group, of which 42 were up-regulated and 77 were down-regulated. The results of the KEGG enrichment analysis on the differential metabolites revealed alterations in metabolic pathways mainly involving primary bile acid biosynthesis, bile secretion, and cholesterol metabolism. Among the differential metabolites, norethisterone was positively correlated with the number of central region crossings (r=0.406, P<0.05); dihydrothymine was negatively correlated with the number of central region crossings (r=−0.346, P<0.05); lysophosphatidylcholine 22∶1 and lysophospholipid 14∶0 were negatively correlated with time spent in central region (r=−0.429, P<0.05; r=−0.374, P<0.05). Conclusion Chronic lead exposure induces anxiety-like behavior in mice, and this altered behavior is associated with altered metabolites in serum, with differential metabolites enriched primarily in the metabolic pathways of primary bile acid biosynthesis, bile acid secretion, and cholesterol metabolism.
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Objective:To investigate the effects of sodium butyrate (NaB) on long-term anxiety like behavior and inflammatory activation of microglia in the hippocampus of sepsis-associated encephalopathy (SAE) mice.Methods:① Animal experiment: fifty C57BL/6 mice aged 6-8 weeks were randomly divided into Sham group (only the cecum was found by laparotomy without perforation or ligation), and SAE model group caused by cecal ligation and puncture (CLP; SAE model group, the cecum was found by laparotomy and perforated after ligation. The open field test indicated that the ability of independent exploration decreased and showed anxiety like behavior, which proved that the SAE model was successfully replicated) and NaB pretreatment group was established (NaB was administered at a dose of 500 mg·kg -1·d -1 for 3 days before modeling, and the same dose once a day for 3 days after modeling). Open field test was used to detect the anxiety like behavior of mice at 7 days. The protein expressions and content changes of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in hippocampus of mice at 1 day and 3 days after operation were detected by Western blotting and enzyme linked immunosorbent assay (ELISA). Immunofluorescence staining was used to observe microglia labeled protein ionized calcium bindingadaptor molecule-1 (Iba-1) and TNF-α protein co localization. ② Cell experiment: mouse microglia cell line BV-2 microglia were divided into blank control group, lipopolysaccharide (LPS) group (cells were treated with 1 mg/L LPS), and NaB treatment group (cells were treated with 1 mg/L LPS+5 mmol/L NaB). The protein expressions of IL-1β, TNF-α, Toll-like receptor 4 (TLR4), phosphorylated nuclear factor-κB p65 (p-NF-κB p65), nuclear factor-κB p65 (NF-κB p65) and NF-κB inhibitor protein-α (IκB-α) were detected by Western blotting. The expressions of Iba-1 and TNF-α in each group were observed by immunofluorescence. Results:① Animal experiment: compared with the Sham group, the distance and duration of movement in the central area, the total distance moved of mice decreased 7 days after the establishment of SAE model group were decreased [distance of movement in the central area (mm): 13.45±3.97 vs. 161.44±27.00, duration of movement in the central area (s): 1.82±0.58 vs. 13.45±2.17, the total distance moved (mm): 835.01±669.67 vs. 2 254.51±213.45, all P < 0.05]. In the hippocampus tissues of mice, a large number of nerve nuclei were pyknotic and deeply stained, and the arrangement of nerve cells was disordered. The cell bodies of microglia in mouse hippocampus increased significantly. The number of positive cells of Iba-1/TNF-α (Iba-1 +/TNF-α +) increased significantly. The contents and protein expression of proinflammatory factors TNF-α, IL-1β in hippocampal homogenate supernatant 3 days after operation in SAE model group were significantly higher than those in Sham group [TNF-α (ng/L): 119.17±18.40 vs. 90.18±21.17, IL-1β (ng/L): 407.89±70.64 vs. 313.69±34.63; TNF-α/GAPDH: 1.42±0.50 vs. 0.80±0.08, IL-1β/GAPDH: 1.27±0.22 vs. 0.85±0.25, all P < 0.05]. After intragastric administration of NaB, the distance and duration of movement in the central area of mice were significantly higher than those in SAE model group [distance of movement in the central area (mm): 47.39±15.63 vs. 13.45±3.97, duration of movement in the central area (s): 6.12±1.87 vs. 1.82±0.58, all P < 0.05]. There was no significant change in the total distance moved (mm: 1 550.59±1 004.10 vs. 835.01±669.67, P > 0.05). The pyknosis and deep staining of nerve nuclei in mice were significantly less than those in SAE model group. The number of Iba-1 +/TNF-α + positive cells decreased significantly. The contents and protein expression levels of proinflammatory factors TNF-α, IL-1β in hippocampal homogenate supernatant 3 days after operation were significantly lower than those in SAE model group [TNF-α (ng/L): 64.95±9.10 vs. 119.17±18.40, IL-1β (ng/L): 311.94±69.92 vs. 407.89±70.64; TNF-α/GAPDH: 1.02±0.36 vs. 1.42±0.50, IL-1β/GAPDH: 0.86±0.20 vs. 1.27±0.22, all P < 0.05]. ② Cell experiment: after LPS intervention, the fluorescence intensity of TNF-α in BV-2 cells was significantly enhanced, the protein expression levels of TNF-α, IL-1β, TLR4 and p-NF-κB p65 protein increased (TNF-α/GAPDH: 0.39±0.06 vs. 0.20±0.02, IL-1β/GAPDH: 0.27±0.03 vs. 0.19±0.01, TLR4/GAPDH: 0.55±0.12 vs. 0.33±0.09, p-NF-κB p65/NF-κB p65: 0.55±0.05 vs. 0.29±0.04, all P < 0.05), the expression level of IκB-α was lower than that in the control group(IκB-α/GAPDH: 0.54±0.06 vs. 0.81±0.03, P < 0.05). After NaB treatment, the fluorescence intensity of TNF-α in BV-2 cells was decreased. The protein expression levels of TNF-α, IL-1β, TLR4 and p-NF-κB p65 protein were significantly lower than that of LPS model group (TNF-α/GAPDH: 0.26±0.02 vs. 0.39±0.06, IL-1β/GAPDH: 0.11±0.04 vs. 0.27±0.03, TLR4/GAPDH: 0.28±0.14 vs. 0.55±0.12, p-NF-κB p65/NF-κB p65: 0.29±0.01 vs. 0.55±0.05, all P < 0.05), the protein expression level of IκB-α was significantly higher than that in the LPS group (IκB-α/GAPDH: 0.75±0.01 vs. 0.54±0.06, P < 0.05). Conclusion:NaB could antagonism the TLR4 activation induced by LPS, thus inhibiting p-NF-κB p65 nuclear transcription and IκB-α degradation. It can reduce microglia activation and secretion of inflammatory factors, and finally improve the inflammation in the hippocampus of septic mice and long-term anxiety like behavior.
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Objective To investigate the effect of Ginkgo biloba extract on behaviors in rat with adolescent sedentariness and its possible mechanism. Methods Twenty-four male SD rats (4-week-old) were randomly divided into normal control (NC), adolescent sedentarines (AS), and Ginkgo biloba extract (GBE) groups. After 4 weeks intervention with GBE, open-field test and elevated plus-maze test were performed to detect the behavioral changes. The content of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) in brain were determined by colorimetric method. Protein levels of glycogen synthase kinase 3β(GSK-3β) and β-catenin in cerebral white matter were determined by Western blotting. Results In open-field test, it was shown that the autonomic activity of rats in AS group increased, while the central regional travel time was reduced. Duration and number of residence in the open arm of elevated plus-maze test decreased in AS group. These anxiety-like behaviors were ameliorated by GBE intervention. Compared with the NC group, GSK-3β/ β-catenin ratio and the content of MDA was upregulated in AS group while downregulated in GBE group. And activity of SOD were downregulated in AS group while significantly upregulated in GBE group (P<0. 05). Conclusion Ginkgo biloba extract ameliorate anxiety-like behavior in rat with adolescent sedentariness. Wnt/ β-catenin pathway and antioxidant regulation may play a cerebral protective role.
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Objective To investigate the effect of voluntary wheel running on negative affective of mice induced by formaldehyde. Methods Thirty male Kunming mice were randomly divided into three groups, including normal saline control group (NS), formaldehyde model group (F), and voluntary wheel running with formaldehyde injection group ( R+ F). The pain model was established by right hindpaw intraplantar formalin injection, the mice of R+F group experienced voluntary wheel running for three weeks before intraplantar formaldehyde injection. The spontaneous pain behavior was determined by the cumulative time of licking paw. The anxiety-like behavior of each group was determined by open field test (OFT) and elevated plus-maze test (EPM) while the depression-like behavior of each group was determined by forced swimming test (FST). The expression of doublecortin ( DCX ) in the hippocampus was determined by immunohistochemistry. Results Compared with the NS group, the typical two-phase pain response was observed in the F group, and compared with the F group, the second phase pain duration was significantly reduced in the R+F group (P<0. 01). In the open field test, the F group showed remarkably reduced time in the inner area(P<0. 001) compared with the NS group, while the R+F group increased time in the inner area (P<0. 05) compared with the F group. In the elevated plus-maze test, the F group showed remarkably reduced time (P< 0. 001) spent in the open arm compared with the NS group, however, compared with the F group, R+F group increased time spent in the open arm (P<0. 05). In the forced swimming test, the immobility time of the F group significant increased (P<0. 01) compared with the NS group, which was decreased in the R+F group (P<0. 05). The Immunohistochemistry showed that the area of DCX positive cells in the hippocampus of the F group was downregulated compared with the NS group, which was upregulated in the R+F group. Conclusion Our findings indicate that voluntary wheel running can improve anxiety and depression-like in mice induced by formaldehyde injection, which may be related to enhanced neurogenesis in the hippocampus.
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OBJECTIVE: To observe the therapeutic effect of acupuncture in the treatment of post-traumatic stress disorder (PTSD)-induced abnormal behavior reactions and learning-memory ability in rats with traumatic injury. METHODS: Sixty male SD rats were randomly divided into control, model, model＋animal capturing (capturing), medication and acupuncture groups (n＝12 rats in each). The PTSD model was established by "electric shock plus incarceration" method. Acupuncture was applied to "Baihui" (GV 20), and unilateral "Neiguan" (PC 6), "Shenmen" (HT 7) and "Taichong" (LR 3) once daily for 12 days. The rats in the medication group were treated by gavage of Paroxetine Hydrochloride solution (0.42 mg/mL), once daily for 12 days. The open field test containing horizontal (crossing grid lines) and rearing tests was performed for examining the rats' locomotor activity and anxiety-like behavior; and location navigation (escape latency) and special probe tests (platform quadrant crossing times) of Morris water maze tasks were detected for assessing the rats' learning-memory ability. On day 12 of the experiments, the rats were submitted to 3 consecutive sessions of open field tests for observing the time of familiar objects (TF) and the time of novelty object (TN) of exploration in 5 min (an object-location and an object-recognition tasks), followed by calculating the discrimination index [DI＝(TN－TF)/(TN＋TF)x100%]. RESULTS: After modeling, compared with the control group, the numbers of crossed grids and rearing, and DI were significantly decreased (P0.05)．. CONCLUSION: Acupuncture can effectively reduce anxiety-like behavior and improve the impaired learning-memory ability in PTSD rats.
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Objective To evaluate the effect of maternal separation stress on the behavior of neonatal rd mice.Methods Neonatal rd mice were divided into maternal separation (MS) group (n=9) and control group (n=9).MS-stress was induced in the MS group by 4-hour-separation per day for 28 days.Open field test,elevated plus maze test,forced swim test and tail suspension test were used to evaluate the anxiety-like and depression-like behavior of the neonatal rd mice.Results The stay time and distance travelled of MS group in the central zone were 0.88％ and 28.17±5.65 cm,respectively,significantly shorter than that of the control group (2.61％,109.9±9.79 cm.P =0.04,P =0.001).Compared with the control group,the stay time in open arms of the MS group was significantly decreased (P<0.01),while the immobility time in forced swim test and tail suspension test of the MS group were 126.5±10.22 s and 21.56±6.83 s,significantly longer than that of the control group (77.75±16.83 s,P =0.02,7.37±3.22 s,P =0.03).Conclutions The 28-day maternal separation stress can significantly increase the anxiety-like and depression-like behavior in neonatal rd mice.
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Objective: To elucidate the anxiolytic and free radical scavenging effect of methanolic extract of Apium graveolens (A. graveolens) in adult C57BL/6 mice. Methods: Sixty male mice were divided into 6 groups:control, vehicle, positive control and A. graveolens (125, 250 and 500 mg/kg). Different behavioral models of elevated plus maze, open field, light/dark, hole-board and pentobarbital-induced sleep were used to assess anxiety-like behavior. Biochemical parameters including monoamine oxidase-A (MAO-A) activity, lipid peroxidation,%inhibition of superoxide anion and glutathione peroxidase activity were measured. Histologic studies were also examined. Results: Mice receiving various doses of A. graveolens (125, 250 and 500 mg/kg) showed an alleviation of anxiety-like behavior as evidenced by the battery of behavioral tests. Likewise, A. graveolens treatment was found to significantly decrease MAO-A activity, lipid peroxidation as well as cause a significant increase of%inhibition of su-peroxide anion and glutathione peroxidase activity in both cortex and striatum. The total number of survival neurons found in the frontal cortex and striatum was significantly higher than that of the vehicle-treated group. Conclusions: Taken together, we showed that A. graveolens improve the behavioral changes which might be related to the inhibition of free radicals and modulation of MAO-A activity resulting in an increased number of survival neurons. Our findings suggest the therapeutic potential of A. graveolens in the treatment of anxiety.
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Objective To elucidate the anxiolytic and free radical scavenging effect of methanolic extract of Apium graveolens (A. graveolens) in adult C57BL/6 mice. Methods Sixty male mice were divided into 6 groups: control, vehicle, positive control and A. graveolens (125, 250 and 500 mg/kg). Different behavioral models of elevated plus maze, open field, light/dark, hole-board and pentobarbital-induced sleep were used to assess anxiety-like behavior. Biochemical parameters including monoamine oxidase-A (MAO-A) activity, lipid peroxidation, % inhibition of superoxide anion and glutathione peroxidase activity were measured. Histologic studies were also examined. Results Mice receiving various doses of A. graveolens (125, 250 and 500 mg/kg) showed an alleviation of anxiety-like behavior as evidenced by the battery of behavioral tests. Likewise, A. graveolens treatment was found to significantly decrease MAO-A activity, lipid peroxidation as well as cause a significant increase of % inhibition of superoxide anion and glutathione peroxidase activity in both cortex and striatum. The total number of survival neurons found in the frontal cortex and striatum was significantly higher than that of the vehicle-treated group. Conclusions Taken together, we showed that A. graveolens improve the behavioral changes which might be related to the inhibition of free radicals and modulation of MAO-A activity resulting in an increased number of survival neurons. Our findings suggest the therapeutic potential of A. graveolens in the treatment of anxiety.
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ObjectiveTo explore the possible mechanism of adult offspring rats'anxiety-like behavior induced by parents experienced morphine addiction and withdrawal.MethodsEstablishing the model of Sprague-Dawley rats morphine addiction,Male and female rats were mated after morphine withdrawal 21 days.Meaning-while,saline control group was established in the same method.5 female and 5 male offspring's brains were obtained to observe the neuronal morphology of hippocampal CA1 through Golgi staining when they were 8 weeks old,the same number of female and male's hippocampus were derived after deeply anesthetized to perform the whole genome expression profiles analysis.ResultsThe total length and the number of basal dendrites branches on hippocampal CA1 neurons in offspring of morphine groups were significantly decreased compared to the offspring of saline group.Comparison with the offspring of saline group,663 up-regulated genes (ratios ≥2.0) and 499 down-regulated genes ( ratios ≤0.5 ) were detected in the male offspring of morphine groups,and 350 up-regulated genes (ratios ≥2.0) and 188 down-regulated genes (ratios ≤0.5) were done in the female.Furthermore,they included many genes associated with regulation of emotional behavior,such as 5-HT2c receptor up-regulation 7-fold,Igf-2 up-regulation 7.1-fold and reelin down-regulation 3.3-fold were observed.ConclusionExperienced morphine addiction and withdrawal in parents prior to mating leads to dysplasia of dendritic morphology in hippocampal CA1 neurons of adult offspring rats,and 5-HT2c,Igf-2,reelin expressing abnormally,which may be the possible mechanism of anxiety-like behavior in adult offspring rats.
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We studied the effects of adverse conditions such as constant light (LL) on the circadian rhythm of malate (MDH, EC 1.1.1.37) and lactate (LDH, EC 1.1.1.27) dehydrogenase activities of the testes of male Wistar rats on postnatal day 28 (PN28), anxiety-like behavior (elevated plus-maze test) at PN60 and sexual behavior at PN120. The rats were assigned to mother groups on day 10 of pregnancy: control (12-h light/dark), LL (light from day 10 to 21 of pregnancy), and LL+Mel (LL and sc injection to the mothers of a daily dose of melatonin, 1 mg/kg body weight at circadian time 12, from day 17 to 21 of pregnancy). LL offspring did not show circadian rhythms of MDH (N = 62) and LDH (N = 63) activities (cosinor and ANOVA-LSD Fisher). They presented a 44.7 percent decrease in open-arm entries and a 67.9 percent decrease in time (plus-maze test, N = 15, P < 0.001, Mann-Whitney U-test and Kruskal-Wallis test), an increase in mounting (94.4 percent), intromission (94.5 percent) and ejaculation (56.6 percent) latencies (N = 12, P < 0.01, Mann-Whitney U-test and Kruskal-Wallis test) and lower numbers of these events (61, 59 and 73 percent, respectively; P < 0.01, N = 12) compared to controls. The offspring of the LL+Mel group presented MDH and LDH circadian rhythms (P < 0.05, N = 50, cosinor and ANOVA-LSD Fisher), anxiety-like and sexual behaviors similar to control. These findings supported the importance of the melatonin signal and provide evidence for the protective effects of hormones on maternal programming during gestation. This protective action of melatonin is probably related to its entrainment capacity, favoring internal coupling of the fetal multioscillatory system.