Open Arms Research Articles

Catechin Protects against Lipopolysaccharide-induced Depressive-like Behaviour in Mice by Regulating Neuronal and Inflammatory Genes.

Many studies have suggested that tea has antidepressant effects; however, the underlying mechanism is not fully studied. As the main anti-inflammatory polyphenol in tea, catechin may contribute to the protective role of tea against depression. The objective of this study is to prove that catechin can protect against lipopolysaccharide (LPS)-induced depressive-like behaviours in mice, and then explore the underlying molecular mechanisms. Thirty-one C57BL/6J mice were categorized into the normal saline (NS) group, LPS group, catechin group, and amitriptyline group according to their treatments. Elevated Plus Maze (EPM), Tail Suspension Test (TST), and Open Field Test (OFT) were employed to assess depressive- like behaviours in mice. RNA sequencing (RNA-seq) and subsequent Bioinformatics analyses, such as differential gene analysis and functional enrichment, were performed on the four mouse groups. In TST, the mice in the LPS group exhibited significantly longer immobility time than those in the other three groups, while the immobility times for the other three groups were not significantly different. Similarly in EPM, LPS-treated mice exhibited a significantly lower percentage in the time/path of entering open arms than the mice in the other three groups, while the percentages of the mice in the other three groups were not significantly different. In OFT, LPS-treated mice exhibited significantly lower percentages in the time/path of entering the centre area than those in the other three groups. The results suggested that the LPS-induced depression models were established successfully and catechin can reverse (LPS)-induced depressive-like behaviours in mice. Finally, RNA-seq analyses revealed 57 differential expressed genes (DEGs) between LPS and NS with 19 up-regulated and 38 down-regulated. Among them, 13 genes were overlapped with the DEGs between LPS and cetechin (in opposite directions), with an overlapping p-value < 0.001. The 13 genes included Rnu7, Lcn2, C4b, Saa3, Pglyrp1, Gpx3, Lyz2, S100a8, S100a9, Tmem254b, Gm14288, Hbb-bt, and Tmem254c, which might play key roles in the protection of catechin against LPS-induced depressive-like behaviours in mice. The 13 genes were significantly enriched in defense response and inflammatory response, indicating that catechin might work through counteracting changes in the immune system induced by LPS. Catechin can protect mice from LPS-induced depressive-like behaviours through affecting inflammatory pathways and neuron-associated gene ontologies.

Evaluation of Anti-Anxiety Activity of Ethanolic Extract of Doronicum Hookeri Rhizome in Swiss Albino Mice

The Aim of this study is the “Evaluation of anti-anxiety activity of Ethanolic Extract of plant Doronicum Hookeri Rhizome in Swiss Albino Mice.” Methods: Twenty Swiss Albino Mice are of either sex selected with weight 20-30gm. Elevated Plus Maze and Light and Dark Exploration test was performed on them with full safety and hygiene. This consists of a 10cm x 10cm central platform, elevated 50cm off the ground, connected to two open arms 50x10cm and two closed arms 50cm x 40cm x 10cm. Swiss albino rats weighing 20-40 g were treated with OS extract, diazepam, and gum arabic for 30 min and then individually placed in the middle of an increasing number of arm diameters. Closing time is 5 minutes for both arms to open and close. Elapsed time is in seconds. The number of entries into the open and closed arms was counted during the test. Entry means that all four paws are on the arms. And in Light and Dark Exploration test: The installation consisted of two square boxes, each measuring 50 cm x 50 cm x 50 cm, separated by wooden walls. One of the boxes is dark and the other is illuminated by a 7W/12V lamp. There is an opening (6 cm x 6 cm) in the middle of the wooden wall that can be opened and closed using a transparent Plexiglas sliding door through which the animals can move from both sides. Mice were placed individually in the center of the light box and monitored for the next 5 min. Time spent in both boxes in seconds. The number of passes in the box is also indicated. Mice were treated with OS extract, diazepam, for 30 min before being placed in the light box. Result: Ethanolic extract of Doronicum Hookeri is found satisfactory, results show the increase in time spent in Open Maze and decreased in closed maze. Similarly time spent in Open Arena is increased as in closed arena. The value is calculated as Controlled, Standard, Low Dose and High Dose. Conclusion: The ethanolic extract showed significant anti-anxiety effect (p&lt;0.04) when compared to control group.

Study of the Behavioral Pattern in Type-2 Diabetic Mice Prepared by Introducing 10% and 15% Fructose Solution

An altered behavioral pattern is a deliberate fact in diabetic conditions that could be induced due to the consumption of foods rich in fructose content. The objective of this research was to develop a fructose-induced diabetic mice model to determine the behavioral changes. Swiss albino mice were involved in this study as the animal model which was subdivided into three groups (control, test groups 1 and 2). Diabetes was induced in test groups 1 and 2 by introducing 10% and 15% fructose solution orally for 8 weeks. After 8 weeks, behavioral tests including hole board test (HBT), tail suspension test (TST), elevated plus maze test (EMT), and forced swim test (FST) were performed to evaluate the behavioral pattern. Findings indicated that test group 1 showed a considerable increase in body weight but only a minor increase in fasting blood glucose (FBG) level than the control group. Neither the behavioral studies for test group 1 stretch any substantial alteration. Whereas test group 2 showed a considerable increase in FBG level and body weight as well as in the behavioral tests. (HBT: 47.87% lower head dipping than the control group; TST: 90.85% higher immobility time than the control group; EMT: 58% lower exploration to open arm than the control group; FST: 38.64% less mobility time than the control group). The findings of the study illustrate that consumption of high concentrations of fructose for long term could have a positive correlation with the induction of type 2 diabetes along with the altered behavioral pattern. Bangladesh Pharmaceutical Journal 27(2): 158-163, 2024 (July)

Embracing AIGC with open arms: advancing equitable healthcare for all in China.

Embracing AIGC with open arms: advancing equitable healthcare for all in China.

Early stress in maternal deprivation affects the expression of OX1R in the limbic system of the brain and contributes to the development of anxiety-depressive symptoms in rats

BACKGROUND: Depressive states are becoming an increasingly common mental disorder and a serious social problem that places a heavy economic burden on society. Increasing data from preclinical and clinical studies indicate that orexins (neuropeptides, also known as hypocretins) and their receptors are involved in the pathogenesis of depression. The orexinergic system regulates disrupted functions in depressive states, such as sleep, reward system, eating behavior, stress response, and monoaminergic regulation. However, the exact role of orexins in behavioral and neurophysiological disorders in depression is still unclear. AIM: This study aimed to examine the effect of early postnatal stress on the expression of OX1R orexin in the limbic system and the development of anxiety-depressive symptoms in rats. MATERIALS AND METHODS: Maternal deprivation was used as a model of early postnatal stress (postpartum days 2–12). The animals were divided into the control (n = 20) and maternal deprivation (n = 20) groups. On day 90 of life, the influence of early postnatal stress on the development of anxiety-depressive symptoms in adult rats was analyzed using a package of behavioral tests, namely, raised cruciform maze, forced swimming Porsolt test, and two-bottle test. After the experiments, the animals were killed by decapitation, the brain was extracted and placed in the cold, and brain structures (hypothalamus and amygdala) were isolated, immediately frozen in liquid nitrogen, and stored at a temperature of −80°C for polymerase chain reaction analysis. RESULTS: In the “raised cruciform maze,” the maternal deprivation group spent less time in the open arms of the maze, and the time spent in the closed sleeves increased relative to the control, which can be assessed as an increase in anxiety levels. In the Porsolt test, the maternal deprivation group had increased immobilization time relative to the control group. In the two-bottle sucrose preference test, the maternal deprivation group demonstrated a decreased preference for sucrose solution, which indicates the development of anhedonia. In the hypothalamus, the mRNA expression level of OX1R significantly decreased in the experimental group compared with that in the control group. A twofold decrease in the mRNA expression level of OX1R was also observed in the amygdala of the experimental group compared with that of the control group. CONCLUSIONS: Early stress caused by maternal deprivation resulted in a decrease in OX1R orexin expression in the hypothalamus and amygdala and contributed to the development of anxiety-depressive symptoms in rats.

Comparative effects of lifelong moderate-intensity continuous training and high-intensity interval training on blood lipid levels and mental well-being in naturally ageing mice

ObjectiveThis study aimed to investigate the impact of lifelong exercise, including both moderate-intensity continuous training and high-intensity interval training, on blood lipid levels and mental behaviour in naturally ageing mice to identify effective exercise strategies for ageing-related health issues. MethodsSix-week-old male BALB/c mice were randomly assigned to one of four groups: young control (YC), natural ageing control (OC), lifelong moderate-intensity continuous exercise (EM), and lifelong high-intensity interval exercise (EH) groups. The EM group was trained at a speed corresponding to 70 % of the maximum running speed, while the EH group was trained at a running speed alternating between 50 % of the maximum running speed, 70 % of the maximum running speed, and 90 % of the maximum running speed. All exercise sessions were conducted three times per week, with each session lasting 50 min. Behavioural tests and blood sample collection were conducted at 72 weeks of age. ResultsAgeing in mice led to changes in muscle and fat mass. Both the EM and EH groups showed greater muscle mass and lower fat mass than did the OC group. Ageing was associated with elevated anxiety (fewer open arm entries, time spent in the central region) and depression (lower sucrose preference) indicators. However, these changes were reversed in both exercise groups, with no differences between the two exercise groups. Blood lipid levels, including total cholesterol (TC), total triglycerides (TGs), low-density lipoprotein (LDL), and free fatty acid (FFA) levels, were greater in the OC group than in the YC group. Additionally, the OC group exhibited lower high-density lipoprotein (HDL) levels. However, both the EM and EH groups exhibited improved lipid profiles compared to those of the YC group. ConclusionLifelong exercise, whether moderate-intensity continuous or high-intensity interval training, can preserve body health during ageing, prevent anxiety and depression, and maintain stable blood lipid levels. Both exercise types are equally effective, suggesting that exercise intensity may not be the critical factor underlying these beneficial adaptations.

Pharmacological evaluation of anxiolytic activity of ethanolic extract of Hemidesmus indicus in rodent model

The current study uses rodent models to explore the anxiolytic properties of Hemidesmus indicus' ethanolic extract (EEHI). Hemidesmus indicus, an evergreen plant well-known for its therapeutic characteristics, has been widely used in Ayurvedic medicine to treat a variety of conditions, including anxiety. This study seeks to give scientific validation for its anxiolytic properties. The ethanolic extract was made using normal extraction processes and given to rodents in varied doses (100,200 and 400 mg/kg). The anxiolytic activity was assessed using a variety of widely recognized behavioural assays, including the Elevated Plus Maze (EPM), Open Field Test (OFT), and Light-Dark Box (LDB) test. Diazepam (2 mg/kg) served as the standard reference drug. The results revealed that EEHI significantly reduced anxiety-like behaviours in all three tests when compared to the control group. In the EPM test, EEHI-treated rodents spent more time and entered the open arms. In the OFT, ambulation, rearing and assisted rearing increased, indicating lower levels of anxiety. The LDB test supported these findings, with a significant increase in time spent in the light compartment. The study suggests that EEHI has promising anxiolytic activity and may offer a natural treatment alternative for anxiety disorders. Further research is needed to isolate specific active molecules and better understand the underlying mechanisms of action. Keywords: Hemidesmus indicus, Anxiolytic activity, Rodent model, Elevated plus maze, Open field test, Light-dark box test

Shikonin ameliorates depressive- and anxiogenic-like behaviors in rats via the suppression of inflammation in the hippocampus

Shikonin is an active naphthoquinone with antioxidative, anti-inflammatory, and anticancer properties. In this study, we investigated the effects of shikonin on depressive- and anxiety-like behaviors in lipopolysaccharide- (LPS-) induced depression and chronic unpredictable mild stress (CUMS) rat models and explored the potential mechanism. First, a 14-day intraperitoneal administration of shikonin (10 mg/kg) significantly decreased immobility time in forced swimming test (FST) and increased open arm entries in elevated plus maze (EPM) test, without affecting line crossings in open field test (OFT), indicating that shikonin has anti-depressant- and anxiolytic-like effects. Second, chronic shikonin administration (10 mg/kg) reversed depressive- and anxiety-like behaviors in LPS-induced and CUMS depression models, as shown in the sucrose preference test (SPT), FST, EPM, and novel object recognition test (NORT). Finally, shikonin significantly reduced the levels of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) in hippocampus, indicating that the anti-depressant- and anxiolytic-like effects of shikonin are related to the reduction of neuroinflammation in hippocampus. These findings suggest that shikonin exerts anti-depressant- and anxiolytic-like effects via an anti-inflammatory mechanism of shikonin in the hippocampus.

Chlordiazepoxide reduces anxiety-like behavior in the adolescent mouse elevated plus maze: A pharmacological validation study

This report evaluates the effects of chlordiazepoxide, a benzodiazepine commonly prescribed to manage anxiety-related disorders in adolescent/pediatric populations, on elevated plus maze (EPM) performance in juvenile mice. This approach was taken because chlordiazepoxide produces anxiolytic-like effects in multiple models in adult rodents, however, less is known about the behavioral effects of this benzodiazepine in juveniles. Thus, we administered a single intraperitoneal injection of chlordiazepoxide (0, 5, or 10 mg/kg) to postnatal day 35 male C57BL/6 mice. Thirty minutes later, mice were allowed to explore the EPM for 5-min. We found that chlordiazepoxide-treated mice (5 and 10 mg/kg) spent more time exploring the open arms of the EPM. No differences in velocity (cm/s) or distance traveled (cm) were observed between the groups. These results indicate that chlordiazepoxide induces anxiolytic-related behavior in adolescent male mice.

A single exposure to the predator odor 2,4,5-trimethylthiazoline causes long-lasting affective behavioral changes in female mice: Modulation by kappa opioid receptor signaling

The volatile compound 2,4,5-trimethylthiazoline (TMT, a synthetic predator scent) triggers fear, anxiety, and defensive responses in rodents that can outlast the encounter. The receptor systems underlying the development and persistence of TMT-induced behavioral changes remain poorly characterized, especially in females. Kappa opioid receptors regulate threat generalization and fear conditioning and alter basal anxiety, but their role in unconditioned fear responses in females has not been examined. Here, we investigated the effects of the long-lasting kappa opioid receptor antagonist, nor-binalthorphinmine dihydrochloride (nor-BNI; 10mg/kg), on TMT-induced freezing and conditioned place aversion in female mice. We also measured anxiety-like behavior in the elevated plus maze three days after TMT and freezing behavior when returned to the TMT-paired context ten days after the single exposure. We found that 35μl of 10% TMT elicited a robust freezing response during a five-minute exposure in female mice. TMT evoked persistent fear as measured by conditioned place aversion, reduced entries into the open arm of the elevated plus maze, and increased general freezing behavior long after TMT exposure. In line with the known role of kappa-opioid receptors in threat generalization, we found that kappa-opioid receptor antagonism increased basal freezing but reduced freezing during TMT presentation. Together, these findings indicate that a single exposure to TMT causes long-lasting changes in fear-related behavioral responses in female mice and highlights the modulatory role of kappa-opioid receptor signaling on fear-related behavioral patterns in females.

Serine racemase deletion alters adolescent social behavior and whole-brain cFos activation.

Neurodevelopmental disorders (NDDs) can cause debilitating impairments in social cognition and aberrant functional connectivity in large-scale brain networks, leading to social isolation and diminished everyday functioning. To facilitate the treatment of social impairments, animal models of NDDs that link N- methyl-D-aspartate receptor (NMDAR) hypofunction to social deficits in adulthood have been used. However, understanding the etiology of social impairments in NDDs requires investigating social changes during sensitive windows during development. We examine social behavior during adolescence using a translational mouse model of NMDAR hypofunction (SR-/-) caused by knocking out serine racemase (SR), the enzyme needed to make D-serine, a key NMDAR coagonist. Species-typical social interactions are maintained through brain-wide neural activation patterns; therefore, we employed whole-brain cFos activity mapping to examine network-level connectivity changes caused by SR deletion. In adolescent SR-/- mice, we observed disinhibited social behavior toward a novel conspecific and rapid social habituation toward familiar social partners. SR-/- mice also spent more time in the open arm of the elevated plus maze which classically points to an anxiolytic behavioral phenotype. These behavioral findings point to a generalized reduction in anxiety-like behavior in both social and non-social contexts in SR-/- mice; importantly, these findings were not associated with diminished working memory. Inter-regional patterns of cFos activation revealed greater connectivity and network density in SR-/- mice compared to controls. These results suggest that NMDAR hypofunction - a potential biomarker for NDDs - can lead to generalized behavioral disinhibition in adolescence, potentially arising from disrupted communication between and within salience and default mode networks.

Differential strain sensitivity to low-dose anxiolytic diazepam in anxiety-related behaviour in male Wistar and Wistar-Kyoto, a rat model of endogenous depression

Objectives: Treatment resistant depression (TRD) prevails among individuals with major depressive disorder (MDD) with comorbid anxiety. The Wistar Kyoto (WKY) rat strain, which demonstrates exaggerated vulnerability to anxiety, has recently been suggested as a model for TRD with similar pathophysiology to MDD, non-responsiveness to antidepressants but responsive to deep brain stimulation and ketamine. At the clinical level, TRD is associated with reduced occipital cortical levels of Gamma-AminoButyric Acid (GABA), with a reduction in spontaneous GABAergic synaptic activity reported in WKY. Diazepam (DZP), a GABA agonist, is a widely used anxiolytic, so the present study was carried out to evaluate its efficacy through a low dose, oral administration in male WKY rats, with the progenitor strain Wistar, serving as vehicular control. Materials and Methods: Adult Wistar and WKY rats were treated with 1 mg/kg body weight DZP administered per os (p. o.) for 10 days. From the 6th day, rats were exposed to a comprehensive battery of behavioural paradigms, including novelty-based open field (OPF), anxiogenic elevated plus maze (EPM), light-dark box (LDB) and the stress coping behaviour assessing forced swim test (FST). Results: DZP reversed the EPM-induced anxiety in Wistars by increasing open-arm duration (P &lt; 0.05), entries (P &lt; 0.05) and exploratory behaviour (P &lt; 0.01) while concomitantly decreasing closed-arm duration (P &lt; 0.05) and entries (P &lt; 0.05), with no effect in WKY. DZP also reduced latency to the dark zone (P &lt; 0.05) in LDB and increased swimming behaviour in FST (P &lt; 0.05) in Wistars, with no effect in WKY. Baseline strain differences were observed with reduced exploratory behaviour in OPF (P &lt; 0.01), open arm entries (P &lt; 0.01) and head dips (P &lt; 0.01) in EPM and swimming (P &lt; 0.05) in FST in WKY as compared to Wistars. Strain differences persisted also in the DZP-treated groups where, as compared to matched Wistars, WKY demonstrated reduced open arm duration (P &lt; 0.05), entries (P &lt; 0.001) and head dips (P &lt; 0.001) and increased closed arm duration (P &lt; 0.001) and entries (P &lt; 0.001) in the EPM. WKY also showed reduced time spent (P &lt; 0.05) and entries (P &lt; 0.01) into the light zone and increased time spent in the dark zone (P &lt; 0.05) of LDB. Further, WKY showed increased immobility (P &lt; 0.05) during habituation and reduced swimming behaviour (P &lt; 0.001) during the test. Conclusion: Strain-specific differences and increased baseline anxiety levels in WKY, as compared to Wistars, induced differential effects of DZP with drug-induced effects observed in Wistars but not in WKY, furthering the treatment resistant aspect of this model. DZP efficacy, therefore, varies in different rat strains and manifests in differential strain-specific responses emanating from exaggerated vulnerability to stress. Results also indicated differential sensitivity of tested paradigms to the anxiolytic activity of DZP and stressed the use of a battery of tests that enable a teasing out of anxiety and depression. However, further studies are needed that would unravel GABAergic differences at the receptor level, such as differential receptor binding affinities, underlying gene polymorphisms and the implications thereof for this TRD model.

Effect of saponins in Panax notoginseng (Burkill) F. H. Chen on the steroid hormone levels in the chronic unpredictable mild stress model of depression in rats

Recent research has indicated that Panax notoginseng saponins (PNS) extracted from the radix of Panax notoginseng (Burkill) F. H. Chen exert antidepressant effects. This study aimed to assess the antidepressive effects of ginsenoside Rg1 and PNS in a depression model induced by chronic unpredictable mild stress (CUMS). Over a period of three weeks, rats were administered ginsenoside Rg1 at a dose of 30 mg/kg and PNS at dosages ranging from 100 to 200 mg/kg body weight per day. To assess how ginsenoside Rg1 and PNS influence depression-like behaviours in rats, various assessments were conducted, including coat state evaluation, forced swim test, and elevated plus maze test. The levels of cortisol and testosterone in serum samples were analysed using the liquid chromatography-electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) method. LC-ESI-MS/MS method provides precise and accurate results. The lower limit of quantification values for cortisol and testosterone were determined as 100 and 2 pg/mL, respectively. Our data demonstrated that both ginsenoside Rg1 and PNS significantly reversed depression-like behaviour in rats by improving coat condition, reducing immobility time in the forced swim test, and increasing time spent in the open arms of the elevated plus maze test. Furthermore, ginsenoside Rg1 and PNS exhibited a regulatory effect on cortisol and testosterone levels in plasma. These findings suggest that ginsenoside Rg1 and PNS may be potential antidepressants in clinical treatment.

The First In Vivo Study Shows That Gyrophoric Acid Changes Behavior of Healthy Laboratory Rats.

Gyrophoric acid (GA), a lichen secondary metabolite, has attracted more attention during the last years because of its potential biological effects. Until now, its effect in vivo has not yet been demonstrated. The aim of our study was to evaluate the basic physicochemical and pharmacokinetic properties of GA, which are directly associated with its biological activities. The stability of the GA in various pH was assessed by conducting repeated UV-VIS spectral measurements. Microsomal stability in rat liver microsomes was performed using Ultra-Performance LC/MS. Binding to human serum albumin (HSA) was assessed using synchronous fluorescence spectra, and molecular docking analysis was used to reveal the binding site of GA to HSA. In the in vivo experiment, 24 Sprague-Dawley rats (Velaz, Únetice, Czech Republic) were used. The animals were divided as follows. The first group (n = 6) included healthy males as control intact rats (♂INT), and the second group (n = 6) included healthy females as controls (♀INT). Groups three and four (♂GA/n = 6 and ♀GA/n = 6) consisted of animals with daily administered GA (10 mg/kg body weight) in an ethanol-water solution per os for a one-month period. We found that GA remained stable under various pH and temperature conditions. It bonded to human serum albumin with the binding constant 1.788 × 106 dm3mol-1 to reach the target tissue via this mechanism. In vivo, GA did not influence body mass gain, food, or fluid intake during the experiment. No liver toxicity was observed. However, GA increased the rearing frequency in behavioral tests (p < 0.01) and center crossings in the elevated plus-maze (p < 0.01 and p < 0.001, respectively). In addition, the time spent in the open arm was prolonged (p < 0.01 and p < 0.001, respectively). Notably, GA was able to pass through the blood-brain barrier, indicating its ability to permeate into the brain and to stimulate neurogenesis in the hilus and subgranular zone of the hippocampus. These observations highlight the potential role of GA in influencing brain function and neurogenesis.

Concomitant Exposure to Lower Doses of Arsenic, Lead, and Manganese Induces Greater Synergistic Neurotoxicity Than Individual Metals in Mice.

People in Bangladesh are often exposed to low to high levels of multiple metals due to contaminated groundwater with various heavy metals such as arsenic (As), lead (Pb), and manganese (Mn). However, the effects of concomitant exposure of these three metals on neurobehavioral changes are yet to be studied. Therefore, this study was intended to assess the neurotoxic effect of As, Pb, and Mn in a mouse model. Elevated plus maze (EPM) and Morris water maze (MWM) tests were conducted to evaluate anxiety, learning, and spatial memory impairment, respectively. The mice exposed to a combination of metals spent least time exploring the open arms and had longer latencies to find the hidden platform than the control and individual metal exposure groups in EPM and MWM tests. Moreover, concomitant multi-metal exposure remarkably decreased the activities of cholinergic and antioxidant enzymes, brain-derived neurotropic factor (BDNF), and nuclear factor erythroid 2-related factor 2 (Nrf2) levels and significantly increased interleukin-6 (IL-6) level in the brain tissue compared to the control and individual metal-exposed mice. Among the mice treated with a single metal, the As-treated mice showed the highest toxic effects than Pb- or Mn-treated mice. Taken together, the present study demonstrated that exposure to a mixture of As, Pb, and Mn, even at lower doses than individual metals, significantly augmented anxiety-like behavior and impaired learning and spatial memory compared to exposure to individual metals, which was associated with the changes of BDNF, Nrf2, IL-6 levels, and related enzyme activities in the brain.

Exposure to 1-nitropyrene after weaning induces anxiety-like behavior partially by inhibiting steroid hormone synthesis in prefrontal cortex

1-Nitropyrene (1-NP) is a neurodevelopmental toxicant. This study was to evaluate the impact of exposure to 1-NP after weaning on anxiety-like behavior. Five-week-old mice were administered with 1-NP (0.1 or 1 mg/kg) daily for 4 weeks. Anxiety-like behaviour was measured using elevated-plus maze (EPM) and open field test (OFT). In EPM test, time spending in open arm and times entering open arm were reduced in 1-NP-treated mice. In OFT test, time spent in the center region and times entering the center region were diminished in 1-NP-treated mice. Prefrontal dendritic length and number of dendrite branches were decreased in 1-NP-treated mice. Prefrontal PSD95, an excitatory postsynaptic membrane protein, and gephyrin, an inhibitory postsynaptic membrane protein, were downregulated in 1-NP-treated mice. Further analysis showed that peripheral steroid hormones, including serum testosterone (T) and estradiol (E2), testicular T, and ovarian E2, were decreased in 1-NP-treated mice. Interestingly, T and E2 were diminished in 1-NP-treated prefrontal cortex. Prefrontal T and E2 synthases were diminished in 1-NP-treated mice. Mechanistically, GCN2-eIF2α, a critical pathway that regulates ribosomal protein translation, was activated in 1-NP-treated prefrontal cortex. These results indicate that exposure to 1-NP after weaning induces anxiety-like behaviour partially by inhibiting steroid hormone synthesis in prefrontal cortex.

Restoration of C-type natriuretic peptide and glial fibrillary acidic protein expression in fear centers and intrinsic cardiac ganglia by theta frequency sound during chronic stress in mice

BackgroundC-type natriuretic peptide (CNP) can be altered during stress and has protective effects in both the heart and brain; the functions of both organs can be positively affected by CNP modulation. Low arousal sounds can modulate heart–brain communication and improve stress responses. Here, we aimed to explore the modulation of CNP and glial fibrillary acidic protein (GFAP) and neuroprotective effects of low arousal theta frequency sound (TFS). MethodsChronic stress was induced in mice (n > 4) using four different stressors on alternate days for 15 days, followed by TFS therapy on alternate days. Open field and elevated plus maze tests were administered for the behavioral analysis, and enzyme-linked immunosorbent assay was used to analyze corticosterone, dopamine, and serotonin levels. Hematoxylin and eosin and cresyl violet staining were used for the morphological analysis of brain and heart sections, and immunohistochemistry for GFAP and CNP was performed. ResultsTFS significantly increased the time spent in the open arms during the elevated plus maze (p< 0.05) and improved exploration in the open field test (p < 0.05). In both tests, decision-making times were significantly reduced by TFS. Nuclear morphology and GFAP expression demonstrated significantly reduced gliosis in fear pathways after TFS therapy x. CNP levels were restored in fear pathways but not intrinsic cardiac ganglia (responsible for heart–brain communication) in TFS-treated mice. Brain corticosterone and dopamine levels increased after TFS therapy, reflecting restored motivational behaviors. ConclusionsLow arousal TFS is a potential neuromodulator for treating stress and related complications.

L-type calcium channel regulation of depression, anxiety and anhedonia-related behavioral phenotypes following chronic stress exposure

Exposure to chronic and unpredictable stressors can precipitate mood-related disorders in humans, particularly in individuals with pre-existing mental health challenges. L-type calcium channels (LTCCs) have been implicated in numerous neuropsychiatric disorders, as LTCC encoding genes have been identified as candidate risk factors for neuropsychiatric illnesses. In these sets of experiments, we sought to examine the ability of LTCC blockade to alter depression, anxiety, and anhedonic-related behavioral responses to chronic unpredictable stress (CUS) exposure in female and male rats. Rats first underwent either 21 days of CUS or no exposure to chronic stressors, serving as home cage controls (HCC). Then rats were examined for anhedonia-related behavior, anxiety and depression-like behavioral responses as measured by the sucrose preference test (SPT), elevated plus maze (EPM), and forced swim test (FST). CUS exposed females and males showed anhedonic and anxiogenic-like behavioral responses on the SPT and EPM, respectively, when compared to HCCs. In female and male rats, systemic administration of the LTCC blocker isradipine (0.4 mg/kg and 1.2 mg/kg, I.P.) attenuated the CUS-induced decrease in sucrose preference and reversed the CUS-induced decrease in open arm time. In the FST, systemic isradipine decreased immobility time across all groups, consistent with an antidepressant-like response. However, there were no significant differences in forced swim test immobility time between HCC and CUS exposed animals. Taken together, these data point to a role of LTCCs in the regulation of mood disorder-related behavioral phenotype responses to chronic stress exposure.

Inhibition of Extracellular Signal-Regulated Kinase Activity Improves Cognitive Function in Mice Subjected to Myocardial Infarction.

Cognitive impairment is a commonly observed complication following myocardial infarction; however, the underlying mechanisms are still not well understood. The most recent research suggests that extracellular signal-regulated kinase (ERK) plays a critical role in the development and occurrence of cognitive dysfunction-related diseases. This study aims to explore whether the ERK inhibitor U0126 targets the ERK/Signal Transducer and Activator of Transcription 1 (STAT1) pathway to ameliorate cognitive impairment after myocardial infarction. To establish a mouse model of myocardial infarction, we utilized various techniques including Echocardiography, Hematoxylin-eosin (HE) staining, Elisa, Open field test, Elevated plus maze test, and Western blot analysis to assess mouse cardiac function, cognitive function, and signal transduction pathways. For further investigation into the mechanisms of cognitive function and signal transduction, we administered the ERK inhibitor U0126 via intraperitoneal injection. Reduced total distance and activity range were observed in mice subjected to myocardial infarction during the open field test, along with decreased exploration of the open arms in the elevated plus maze test. However, U0126 treatment exhibited a significant improvement in cognitive decline, indicating a protective effect through the inhibition of the ERK/STAT1 signaling pathway. Hence, this study highlights the involvement of the ERK/STAT1 pathway in regulating cognitive dysfunction following myocardial infarction and establishes U0126 as a promising therapeutic target.

Maternal and filial consumption of probiotics protects from acute stress-induced anxiety and loss of benevolent gut microbes.

The study aimed to determine the effects of probiotic consumption during pregnancy and lactation and post-weaning on acute stress-induced anxiety and gut beneficial microbiota of the female offspring mice.The female offspring mice were divided into several groups: intact, control (only stressed), PBS/dam (dams gavaged with PBS), PRO/dam (dams gavaged with probiotics), PRO/dam+off (both dams and offspring gavaged with probiotics), and PBS/dam+off (both dams and offspring gavaged with PBS)The probiotics chosen are mainly L. rhamnosus, B.breve, and B. longum (108 CFU/ml). Foot shock stress will be applied for one hour on the 43rd day after birth. Behavioral tests were conducted using the open field and elevated plus-maze. Corticosterone was measured by ELISA kit, and intestinal microflora with qPCR.The data showed that PRO/dam+off had more entries into open arms compared to the control group and decreased move distance and time spent in closed arms compared to the control group. However, there was no significant difference between the PRO/dam group and the control group. In the open field test, the control group spent less time in the inner zone compared to the intact group and in PRO/dam+off group. Corticosterone hormone was increased in the control group and was decreased in the PRO/dam+off. Bifidobacteria and Lactobacilli decreased in the control group in comparison to the intact group, and in the PRO/dam+off group increased compared with other groups. Maternal and filial supplementation with a multi-strain probiotic mixture increased levels of beneficial bacteria and reduced stress-induced anxiety in mice.