OBJECTIVE: To elucidate the modulation mechanism of Suanzaoren Decoction (SZRD) on basolateral amygdala (BLA) neuronal activity to alleviate chronic restraint stress (CRS)-related behavioral deficits. METHODS: The male C57BL/6J mice were assigned to 4 groups using the complete randomization method, including control (CON, n=19), CRS (n=19), SZRD (n=21), and fluoxetine (Flu, n=22) groups. Mice were restrained for 6 h per day, over a 21-d period to establish CRS models. The CON group remained in their cages without food or water during the 6-h matching period. SZRD and Flu groups received intragastric administration of SZRD (4.68 g/kg) and Flu (20 mg/kg) daily, respectively, 30 min before restraint for 21 consecutive days. The therapeutic effects of SZRD were evaluated using behavioral tests including the tail suspension test, elevated plus maze test, and forced swimming test. The cellular Fletcher B. Judson murine osteosarcoma proto-oncogene (c-Fos) expression in the BLA was measured using immunofluorescence, while action potential (AP) firing and synaptic transmission in BLA pyramidal neurons were evaluated using whole-cell patch-clamp recordings. RESULTS: SZRD administration significantly increased time spent in the open arms and open-arm entries while reducing immobility time (P<0.05 or P<0.01). It downregulated CRS-induced c-Fos expression and AP firing of pyramidal neurons in the BLA (P<0.01). Additionally, SZRD selectively attenuated excitatory (P<0.01), but not inhibitory, synaptic transmission onto BLA pyramidal neurons. CONCLUSION SZRD alleviated CRS-induced anxiety- and depression-like behaviors in mice by modulating the excitability and synaptic transmission of BLA pyramidal neurons.
Animals ; Drugs, Chinese Herbal/therapeutic use* ; Depression/complications* ; Pyramidal Cells/pathology* ; Male ; Mice, Inbred C57BL ; Basolateral Nuclear Complex/pathology* ; Restraint, Physical ; Anxiety/complications* ; Behavior, Animal/drug effects* ; Stress, Psychological/physiopathology* ; Mice ; Proto-Oncogene Proteins c-fos/metabolism* ; Action Potentials/drug effects* ; Synaptic Transmission/drug effects*

OBJECTIVES: To investigate the mechanism by which the pyramidal neurons of the anterior cingulate cortex (ACC) modulate the effects of enriched environment (EE) for relieving anxiety-like behaviors in mice. METHODS: C57BL/6J mice were randomly divided into control group, restraint stress (RS) group, and RS+EE group (n=8). The mice in the latter two groups were subjected to RS for 2 h daily for 3 days, and those in RS+EE group were housed in an EE during modeling. Anxiety-like behaviors of the mice were evaluated using the elevated plus-maze tests (EPM) and open field test (OFT). Changes in c-Fos expression in the ACC of the mice were detected with immunofluorescence assay, and pyramidal neuron excitability in the ACC (Pyn^ACC) was measured using patch-clamp technique. The miniature excitatory and inhibitory postsynaptic currents (mEPSC and mIPSC, respectively) were analyzed to assess synaptic transmission changes. RESULTS: Behavioral tests showed obvious anxiety-like behaviors in RS mice, and such behavioral changes were significantly improved in RS+EE mice. Immunofluorescence staining revealed significantly increased c-Fos expression in the ACC in RS mice but lowered c-Fos expression in RS+EE group. Compared with the control mice, the RS mice showed increased action potential firing rate of Pyn^ACC, which was significantly reduced in RS+EE group. Compared with the RS mice, the RS+EE mice showed also decreased frequency of mEPSCs of Pyn^ACC, but the amplitude exhibited no significant changes. No obvious changes in the frequency or amplitude of mIPSCs were observed in RS+EE mice. CONCLUSIONS EE reduces excitability of Pyn^ACC to alleviate anxiety-like behaviors induced by RS in mice.
Animals ; Anxiety/physiopathology* ; Gyrus Cinguli ; Mice, Inbred C57BL ; Mice ; Pyramidal Cells/physiology* ; Restraint, Physical ; Stress, Psychological ; Proto-Oncogene Proteins c-fos/metabolism* ; Male ; Behavior, Animal ; Environment ; Excitatory Postsynaptic Potentials

Growth arrest DNA damage-inducible protein 45 β (GADD45B) has been reported to be a regulatory factor for active DNA demethylation and is implicated in the modulation of synaptic plasticity and chronic stress-related psychopathological processes. However, its precise role and mechanism of action in stress susceptibility remain elusive. In this study, we found a significant reduction in GADD45B expression specifically in the ventral, but not the dorsal hippocampal CA1 (dCA1) of stress-susceptible mice. Furthermore, we demonstrated that GADD45B negatively regulates susceptibility to social stress and NMDA receptor-dependent long-term potentiation (LTP) in the ventral hippocampal CA1 (vCA1). Importantly, through pharmacological inhibition using the NMDA receptor antagonist MK801, we provided further evidence supporting the hypothesis that GADD45B potentially modulates susceptibility to social stress by influencing NMDA receptor-mediated LTP. Collectively, these results suggested that modulation of NMDA receptor-mediated synaptic plasticity is a pivotal mechanism underlying the regulation of susceptibility to social stress by GADD45B.
Animals ; Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors* ; CA1 Region, Hippocampal/drug effects* ; Male ; Stress, Psychological/physiopathology* ; Mice ; Neuronal Plasticity/drug effects* ; Long-Term Potentiation/drug effects* ; Mice, Inbred C57BL ; Antigens, Differentiation/metabolism* ; Dizocilpine Maleate/pharmacology* ; Excitatory Amino Acid Antagonists/pharmacology* ; GADD45 Proteins

In modern society, people are increasingly exposed to chronic stress, leading to various mental disorders. However, the activities of brain regions, especially neural firing patterns related to specific behaviors, remain unclear. In this study, we introduce a novel approach, NeuroSync, which integrates open-field behavioral testing with electrophysiological recordings from emotion-related brain regions, specifically the central amygdala and the paraventricular nucleus of the hypothalamus, to explore the mechanisms of negative emotions induced by chronic stress in mice. By applying machine vision techniques, we quantified behaviors in the open field, and signal processing algorithms elucidated the neural underpinnings of the observed behaviors. Synchronizing behavioral and electrophysiological data revealed significant correlations between neural firing patterns and stress-related behaviors, providing insights into real-time brain activity underlying behavioral responses. This research combines deep learning and machine learning to synchronize high-resolution video and electrophysiological data, offering new insights into neural-behavioral dynamics under chronic stress conditions.
Animals ; Mice ; Male ; Emotions/physiology* ; Stress, Psychological/physiopathology* ; Action Potentials/physiology* ; Mice, Inbred C57BL ; Behavior, Animal/physiology* ; Machine Learning ; Amygdala/physiopathology* ; Neurons/physiology* ; Paraventricular Hypothalamic Nucleus/physiopathology* ; Brain/physiology*

OBJECTIVES: During pregnancy, pregnant women are prone to stress reactions due to external stimuli, affecting their own health and fetal development. At present, there is no good treatment for the stress reactions from pregnant women during pregnancy. This study aims to explore the effect of probiotics on abnormal behavior and hippocampal injury in pregnant stressed offspring. METHODS: SD pregnant rats were divided into a control group, a stress group, and a probiotics group, with 6 rats in each group. The control group was untreated; the stress group was given restraint stress on the 15th-20th day of pregnancy; the probiotics group was given both bifidobacterium trisporus capsules and restraint stress on the 15th-20th day of pregnancy, and the offspring continued to be fed with probiotics until 60 days after birth (P60). The offspring rats completed behavioral tests such as the open field test, the elevated plus maze test, the new object recognition test, and the barnes maze test at 60-70 d postnatally. Nissl's staining was used to reflect the injury of hippocampal neurons; immunohistochemical staining was used to detect the expression of microglia marker ionized calcium binding adapter molecule 1 (IBA-1) which can reflect microglia activation; ELISA was used to detect the content of plasma TNF-α and IL-1β; Western blotting was used to detect the expression of Bax, Bcl-2, and caspase-3. RESULTS: The retention time of offspring rats in the stress group in the central area of the open field was significantly less than that in the control group (P<0.01), and the retention time of offspring rats in the probiotic group in the central area of the open field was significantly more than that in the stress group (P<0.05). The offspring rats in the stress group stayed in the open arm for a shorter time than the control group (P<0.05) and entered the open arm less often than the control group (P<0.01); the offspring rats in the probiotic group stayed in the open arm for a longer time than the stress group and entered the open arm more often than the stress group (both P<0.05). The discrimination ratio for new to old objects in the offspring rats of the stress group was significantly lower than that of the control group (P<0.01), and the discrimination ratio for new to old objects in the offspring rats of the probiotic group was significantly higher than that of the stress group (P<0.05). The offspring rats in the stress group made significantly more mistakes than the control group (P<0.05), and the offspring rats in the probiotic group made significantly fewer mistakes than the stress group (P<0.05). Compared with the control group, the numbers of Nissl bodies in CA1, CA3, and DG area were significantly reduced in the offspring rats of the stress group (all P<0.001), the number of activated microglia in DG area of hippocampus was significantly increased (P<0.01), the contents of TNF-α and IL-1β in peripheral blood were significantly increased (P<0.05 or P<0.01), the protein expression level of Bcl-2 was significantly down-regulated, and the protein expression levels of Bax and caspase-3 were significantly up-regulated (all P<0.001). Compared with the stress group, the numbers of Nissl bodies in CA1, CA3, and DG area were significantly increased in the probiotic group offspring rats (P<0.001, P<0.01, P<0.05), the number of activated microglia in the DG area of hippocampus was significantly reduced (P<0.05), and the TNF-α and IL-1β levels in peripheral blood were significantly decreased (both P<0.05), the protein expression level of Bcl-2 was significantly up-regulated, and the protein expression levels of Bax and caspase-3 were significantly down-regulated (all P<0.001). CONCLUSIONS Probiotic intervention partially ameliorated anxiety and cognitive impairment in rats offspring of pregnancy stress, and the mechanism may be related to increasing the number of neurons, inhibiting the activation of hippocampal microglia, and reducing inflammation and apoptosis.
Animals ; Caspase 3/metabolism* ; Female ; Hippocampus/physiopathology* ; Humans ; Pregnancy ; Probiotics/therapeutic use* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Rats ; Stress, Psychological/therapy* ; Tumor Necrosis Factor-alpha/metabolism* ; bcl-2-Associated X Protein/metabolism*

Chronic stress is generally accepted as the main risk factor in the development of cognitive decline; however, the underlying mechanisms remain unclear. Previous data have demonstrated that the levels of homocysteine (Hcy) are significantly elevated in the plasma of stressed animals, which suggests that Hcy is associated with stress and cognitive decline. To test this hypothesis, we analyzed the cognitive function, plasma concentrations of Hcy, and brain-derived neurotropic factor (BDNF) levels in rats undergoing chronic unpredicted mild stress (CUMS). The results showed that decreased cognitive behavioral performance and decreased BDNF transcription and protein expression were correlated with hyperhomocysteinemia (HHcy) levels in stressed rats. Diet-induced HHcy mimicked the cognitive decline and BDNF downregulation in the same manner as CUMS, while Hcy reduction (by means of vitamin B complex supplements) alleviated the cognitive deficits and BDNF reduction in CUMS rats. Furthermore, we also found that both stress and HHcy disturbed the DNA methylation process in the brain and induced DNA hypermethylation in the BDNF promoter. In contrast, control of Hcy blocked BDNF promoter methylation and upregulated BDNF levels in the brain. These results imply the possibility of a causal role of Hcy in stress-induced cognitive decline. We also used ten-eleven translocation (TET1), an enzyme that induces DNA demethylation, to verify the involvement of Hcy and DNA methylation in the regulation of BDNF expression and the development of stress-related cognitive decline. The data showed that TET1-expressing viral injection into the hippocampus inhibited BDNF promoter methylation and significantly mitigated the cognitive decline in HHcy rats. Taken together, novel evidence from the present study suggests that Hcy is likely involved in chronic stress-induced BDNF reduction and related cognitive deficits. In addition, the negative side-effects of HHcy may be associated with Hcy-induced DNA hypermethylation in the BDNF promoter. The results also suggest the possibility of Hcy as a target for therapy and the potential value of vitamin B intake in preventing stress-induced cognitive decline.
Animals ; Brain-Derived Neurotrophic Factor/metabolism* ; Cognitive Dysfunction/complications* ; DNA Methylation ; Homocysteine/metabolism* ; Hyperhomocysteinemia/metabolism* ; Rats ; Stress, Psychological/physiopathology*

Restraint water-immersion stress (RWIS), a compound stress model, has been widely used to induce acute gastric ulceration in rats. A wealth of evidence suggests that the central nucleus of the amygdala (CEA) is a focal region for mediating the biological response to stress. Different stressors induce distinct alterations of neuronal activity in the CEA; however, few studies have reported the characteristics of CEA neuronal activity induced by RWIS. Therefore, we explored this issue using immunohistochemistry and in vivo extracellular single-unit recording. Our results showed that RWIS and restraint stress (RS) differentially changed the c-Fos expression and firing properties of neurons in the medial CEA. In addition, RWIS, but not RS, induced the activation of corticotropin-releasing hormone neurons in the CEA. These findings suggested that specific neuronal activation in the CEA is involved in the formation of RWIS-induced gastric ulcers. This study also provides a possible theoretical explanation for the different gastric dysfunctions induced by different stressors.
Action Potentials ; drug effects ; physiology ; Analysis of Variance ; Animals ; Central Amygdaloid Nucleus ; pathology ; Corticotropin-Releasing Hormone ; metabolism ; Disease Models, Animal ; Gastric Mucosa ; pathology ; Gene Expression Regulation ; physiology ; Neurons ; physiology ; Patch-Clamp Techniques ; Proto-Oncogene Proteins c-fos ; metabolism ; Rats ; Rats, Wistar ; Stress, Physiological ; physiology ; Stress, Psychological ; etiology ; physiopathology

OBJECTIVETo establish social stress induced depression-like model in mice of C57BL/6 strain, and to assess its reliability using differenf behavioral methods.

METHODSTotally 20 male mice of C57BL/6 strain were divided into the normal group and the stress model group by random digit table,10 in each group. Another 10 CD1 mice were subjected to social stress. Mice in the normal control group received no stress, while those in the model group received social stress for 10 successive days. Behavioral assessment was performed using social interaction test (SIT), the elevated plus-maze (EPM) test, tail suspension test (TST), respectively. Serum cortisol level was detected by ELISA to assess the reliability of the model.

RESULTSIn the social interaction test when the social target (CDI mice) was inexistent, mice in the normal control group spent longer time in the social interaction zone and less time in the corner zone (P < 0.05); mice in the model group spent less time in the social interaction zone and more time in the corner zone (P < 0.05). Compared with the normal group when CDI mice existed, mice in the model group spent less time in the social interaction zone and more time in the corner zone (P < 0.05). Compared with the normal control group, the total times for entry into open arms, close arms, and the maze were obviously reduced (P < 0.05), and the proportion of entering open arms was significantly reduced (P < 0.05) in the model group. In TST, the motionless time within the last 4 mm was prolonged in the model group (P < 0.05). The serum cortisol level in the model group was obviously elevated (P < 0.01).

CONCLUSIONSocial stress induced depression-like animal model in mice of C57BL/6 straineasquite reliable and possibly suitable to be used in integrative medicine research of combination of disease and syndrome model.

Animals ; Behavior, Animal ; Depression ; physiopathology ; Disease Models, Animal ; Hydrocortisone ; blood ; Male ; Mice ; Mice, Inbred C57BL ; Social Behavior ; Stress, Psychological

PURPOSE: Fatigue is the third most common "extraintestinal" complaint of patients with irritable bowel syndrome (IBS), but it is still poorly understood. This study aimed to review characteristics of IBS-associated fatigue and to examine pooled frequency, severity of fatigue, and correlations of related factors with fatigue in IBS via meta-analyses. METHODS: Publications were searched in eight databases from 1995 to 2014. Random effects meta-analyses were applied with standard error, weighted effect size, and correlation-based measure of effect size. RESULTS: Twenty-four studies were included in systematic review. Seventeen studies were used for meta-analyses (2 studies were excluded in the frequency of fatigue analysis due to data unavailability). Using "tiredness" to define fatigue, and Fatigue Impact Scale to assess fatigue were the most frequently used across the studies. Gastrointestinal symptoms, psychological distress, and health-related quality of life were the most common correlates with fatigue. The pooled frequency of fatigue was 54.2% [95% confidence interval (38.5, 69.4)]. Metaregression on the frequency of fatigue showed positive and significant relations with tertiary care settings, female sex, and younger age. There was a negatively moderate relationship between the severity of fatigue and health-related quality of life score (correlation-based measure of effect size: -.378). CONCLUSIONS: Fatigue is prevalent among patients with IBS and commonly co-occurs with other symptoms. This is the first study to fully examine fatigue in IBS, which shed light on the comprehensive management of fatigue in this patient group. Future research is warranted to further explore fatigue-related factors and underlying mechanisms of fatigue in IBS.
Adult ; Age Factors ; Aged ; Fatigue/*etiology/*nursing ; Female ; Humans ; Irritable Bowel Syndrome/*complications/*physiopathology ; Male ; Middle Aged ; Prevalence ; *Quality of Life ; Severity of Illness Index ; Sex Factors ; Stress, Psychological

PURPOSE: To determine the impact of noise on heart rate variability (HRV) in men, with a focus on the noise type rather than on noise intensity. MATERIALS AND METHODS: Forty college-going male volunteers were enrolled in this study and were randomly divided into four groups according to the type of noise they were exposed to: background, traffic, speech, or mixed (traffic and speech) noise. All groups except the background group (35 dB) were exposed to 45 dB sound pressure levels. We collected data on age, smoking status, alcohol consumption, and disease status from responses to self-reported questionnaires and medical examinations. We also measured HRV parameters and blood pressure levels before and after exposure to noise. The HRV parameters were evaluated while patients remained seated for 5 minutes, and frequency and time domain analyses were then performed. RESULTS: After noise exposure, only the speech noise group showed a reduced low frequency (LF) value, reflecting the activity of both the sympathetic and parasympathetic nervous systems. The low-to-high frequency (LF/HF) ratio, which reflected the activity of the autonomic nervous system (ANS), became more stable, decreasing from 5.21 to 1.37; however, this change was not statistically significant. CONCLUSION: These results indicate that 45 dB(A) of noise, 10 dB(A) higher than background noise, affects the ANS. Additionally, the impact on HRV activity might differ according to the noise quality. Further studies will be required to ascertain the role of noise type.
Adaptation, Psychological ; Confounding Factors (Epidemiology) ; Environment ; Heart Rate/*physiology ; Humans ; Male ; *Noise ; Questionnaires ; Stress, Psychological/physiopathology ; Young Adult