Reversal of reserpine-induced depression and cognitive disorder in zebrafish by sertraline and Traditional Chinese Medicine (TCM)

Sceletium tortuosum-derived mesembrine significantly contributes to the anxiolytic effect of Zembrin®, but its anti-depressant effect may require synergy of multiple plant constituents

ETHNOPHARMACOLOGY RELEVANCE

Sceletium tortuosum (L.) N.E.Br. (ST) is an alkaloid-rich succulent plant with various mechanisms of action that infer psychotropic effects. These actions correlate with clinical evidence suggesting efficacy in the treatment of depression and anxiety, in line with its use by indigenous populations. Its low side effect profile suggests potential of ST to improve the overall wellbeing and compliance of millions of patients that experience severe side effects and/or do not respond to current prescription medication. However, to elucidate specific physiological effects of ST extracts, it is necessary to first understand which of its constituents are the major contributors to beneficial effects demonstrated for ST in this context.

AIM OF THE STUDY

To determine an anxiolytic- and antidepressant-like effective concentration of a ST extract by means of a dose response in zebrafish (ZF) larvae, and to assess relative contributions of equivalent concentrations of isolated alkaloids contained in the effective concentration(s).

MATERIALS AND METHODS

A dose response study employing a light-dark transition test (LDTT) was done in ZF larvae (<5 days post fertilization) to track locomotor activity in terms of anxiety-like (hyperlocomotion) and depression-like (hypolocomotion) behaviour. Larvae were treated for 1 h directly before the LDTT with escalating concentrations of a ST extract commercially known as Zembrin® (Zem) ranging from 0.25 to 500 μg/mL and compared to an untreated control group (n = 12 per treatment concentration). LDTT was repeated after 24 h to evaluate long-term exposure toxicity. The concentration that best attenuated hyperlocomotion during the dark phase following light-dark transition was identified as the anxiolytic-like concentration. This concentration, plus one higher and one lower concentration, were used for subsequent tests. The percentage content of each alkaloid (mesembrine, mesembrenone, mesembrenol, and mesembranol) in these concentrations were calculated and applied to additional larvae to identify the most effective anxiolytic-like alkaloid in the LDTT. To identify antidepressant-like therapeutic concentration and equivalent alkaloid concentration, the same treatment concentrations were tested in larvae (n = 12 per treatment concentration) pre-exposed to reserpine for 24 h. Depending on normality of data distribution, Brown-Forsythe and Welch, or Kruskal-Wallis ANOVA were used, with Dunnett or Dunn's multiple comparisons tests.

RESULTS

Only the extreme concentration of Zem (500 μg/mL) elicited toxicity after treatment for 24 h. Zem 12.5 μg/mL was the most effective anxiolytic-like concentration as it significantly decreased locomotor activity (P = 0.05) in the LDTT. Low (5 μg/mL), optimal (12.5 μg/mL) and high (25 μg/mL) Zem concentrations, as well as treatment solutions of single alkaloids (mesembrine, mesembrenone, mesembranol and mesembrenol), prepared to contain equivalent concentrations of each major alkaloid contained within these three concentrations of Zem, were tested further. Only mesembrine concentrations equal to that contained within the optimal and high dose of Zem (12.5 and 25 μg/mL) showed significant anxiolytic-like effects (P < 0.05). Only the highest Zem concentration (25 μg/mL) reversed the effects of reserpine - indicating antidepressant-like properties (P < 0.05) - while isolated alkaloids failed to induce such effects when administered in isolation.

CONCLUSIONS

Current data provide evidence of both anxiolytic- and antidepressant-like effect of whole extract of Zem, with relatively higher concentrations required to achieve antidepressant-like effect. Of all alkaloids assessed, only mesembrine contributed significantly to the anxiolytic-like effects of Zem. No alkaloid alone could be pinpointed as a contributor to the antidepressant-like activity observed for higher concentration Zem. This may be due to synergistic effects of the alkaloids or may be due to other components not tested here. Current data warrants further investigation into mechanisms of action, as well as potential synergy, of ST alkaloids in suitable mammalian in vivo models.

Fluoxetine rescues the depressive-like behaviour induced by reserpine and the altered emotional behaviour induced by nicotine withdrawal in zebrafish: Involvement of tyrosine hydroxylase

BACKGROUND

Nicotine cessation leads to anxiety and depression.

AIMS

The suitability of the zebrafish model of anhedonia using reserpine and fluoxetine was evaluated. Fluoxetine was also used to reduce nicotine withdrawal-induced anhedonic state.

METHODS

Zebrafish were exposed to reserpine (40 mg/l) and then to fluoxetine (0.1 mg/l) for 1 week. Anhedonia was evaluated in the Novel Tank Diving and Compartment Preference tests. Another group was exposed to nicotine (1 mg/l/2 weeks) and then exposed to fluoxetine. Anxiety and anhedonia were evaluated 2-60 days after. Tyrosine hydroxylase (TH) immunoreactivity and microglial morphology (labelled by 4C4 monoclonal antibody) in the parvocellular pretectal nucleus (PPN), dorsal part, and of calcitonin gene-related peptide (CGRP) in the hypothalamus were also analysed.

RESULTS

Less time in the top and increased latency to the top in reserpine compared to a drug-free group was found. Fluoxetine rescued reserpine-induced the reduced time in the top. Seven and 30 days after nicotine withdrawal more time in the bottom and similar time in the Compartment Preference test, rescued by fluoxetine, were shown. In the PPN, 30-day withdrawal induced an increase in TH immunoreactivity, but fluoxetine induced a further significant increase. No changes in PPN microglia morphology and hypothalamic CGRP were detected.

CONCLUSIONS

Our findings validate the suitability of the zebrafish model of anhedonia using the reserpine-induced depression-like behaviour and the predictivity using fluoxetine. Fluoxetine rescued nicotine withdrawal-induced anhedonic state, opening the possibility to screen new drugs to alleviate anxiety and depression in smokers during abstinence.

Color Perspectives in Aquatic Explorations: Unveiling Innate Color Preferences and Psychoactive Responses in Freshwater Crayfish

Color preference assay is a test for an animal's innate and adaptive response to differentiate colors and can be used as an endpoint for psychoactive activity evaluation. Several color preference test methods in aquatic animals that can be used to perform behavioral screening have been established. However, the color preference test conditions have yet to be extensively studied and standardized in aquatic invertebrates. This study aimed to replicate and optimize the previously published method to evaluate the potential color preference in freshwater crayfish based on four different approaches: species, life stages, sex, and pharmaceutical exposure. Using the optimized setup, two crayfish species display color preferences to some specific colors. P. clarkii displays more dominant color preference behavior than C. quadricarinatus in terms of color preference ranking and index. P. clarkii prefers the red color compared to other colors (red > green > blue > yellow), while C. quadricarinatus dislikes yellow compared to other colors (blue = green = red > yellow). Since P. clarkii has a more obvious color index ranking and several advantages compared to C. quadricarinatus, we conducted further tests using P. clarkii as an animal model. In the juvenile and adult stages of P. clarkii, they prefer red and avoid yellow. However, the juvenile one did not display a strong color preference like the adult one. Different sex of crayfish displayed no significant differences in their color preference responses. In addition, we also evaluated the potential effect of the antidepressant sertraline on color preference in P. clarkii and found that waterborne antidepressant exposure can significantly alter their color preference. This fundamental information collected from this study supports the crayfish color preference test as a good behavioral test to address environmental pollution.

Research on Xiaoyao Powder in the treatment of depression based on epigenetics and quality markers

Depression has become one of the most common public health issues around the world, and the incidence has been increasing in recent years. A large amount of clinical investigations have proven that the treatment of depression is difficult. The prognosis is poor, and the fatality rate is high. At present, western medicine is the preferred treatment for depression, but it often causes adverse clinical reactions such as dry mouth, blurred vision, and memory loss, etc. The herbal compound Xiaoyao Powder is a traditional medicine for soothing the liver and relieving depression, strengthening the spleen, and nourishing the blood. It can reduce adverse reactions. It is effective in treating depression. In this study, we elucidate the function of Xiaoyao Powder in anti-depression from the perspective of clinical application and pharmacological mechanisms such as regulating epigenetic and chemical quality markers to provide empirical and experimental theoretical results that contribute to developing future depression therapy with Xiaoyao Powder.

Cardamom oil ameliorates behavioral and neuropathological disorders in a rat model of depression induced by reserpine

ETHNOPHARMACOLOGICAL RELEVANCE

Depression is a public health problem. Despite the availability of treatment options, its prevalence is increasing. A high rate of treatment failure is often reported, along with considerable side effects associated with synthetic antidepressants. Therefore, developing effective and safe antidepressants from traditional herbs or natural products as an alternative strategy is warranted to avoid side effects and increase drug efficacy. In traditional medicine, cardamom has traditionally been used to treat conditions like asthma, tooth and gum infections, cataracts, nausea, diarrhea, and even depression and anxiety as well as some problems with the heart, kidneys, and digestive system.

AIM OF THE STUDY

The current study aimed to evaluate the antidepressant activity of cardamom oil in a rat model of depression induced by reserpine and compare it with the activity of the antidepressant drug fluoxetine.

MATERIALS AND METHODS

Depression-like symptoms were induced in male rats by daily i. p. injection of reserpine (0.2 mg/kg/d for 15 d followed by 0.1 mg/kg/d for 21 d to maintain the depressive state), and the rats were treated with cardamom oil (oral dose = 200 mg/kg/d) for 21 d along with the maintenance dose of reserpine. We performed behavioral tests (forced swimming test and open-field test) and evaluated biochemical markers of depression.

RESULTS

Our findings revealed that cardamom oil attenuated depression-like symptoms in reserpine-injected rats by improving the behavioral changes measured by the forced swimming test and the locomotor activities measured by the open-field test. In reserpine-injected rats, cardamom oil exerted antidepressant-like effects by modulating lower levels of brain monoamine neurotransmitters (serotonin, norepinephrine, and dopamine), GSH, and higher oxido-nitrosative stress parameters (malondialdehyde and nitric oxide). Moreover, cardamom oil alleviated depression-like behaviors by lowering monoamine oxidase activity and raising the activities of Na⁺/K⁺-ATPase and acetylcholinesterase and levels of a brain-derived neurotrophic factor in the cortex and hippocampus.

CONCLUSION

We recommend the use of cardamom oil as a safe and reliable treatment or an adjuvant for preventing depression-like symptoms in patients suffering from depression.

High fried food consumption impacts anxiety and depression due to lipid metabolism disturbance and neuroinflammation

Western dietary patterns have been unfavorably linked with mental health. However, the long-term effects of habitual fried food consumption on anxiety and depression and underlying mechanisms remain unclear. Our population-based study with 140,728 people revealed that frequent fried food consumption, especially fried potato consumption, is strongly associated with 12% and 7% higher risk of anxiety and depression, respectively. The associations were more pronounced among male and younger consumers. Consistently, long-term exposure to acrylamide, a representative food processing contaminant in fried products, exacerbates scototaxis and thigmotaxis, and further impairs exploration ability and sociality of adult zebrafish, showing anxiety- and depressive-like behaviors. Moreover, treatment with acrylamide significantly down-regulates the gene expression of tjp2a related to the permeability of blood-brain barrier. Multiomics analysis showed that chronic exposure to acrylamide induces cerebral lipid metabolism disturbance and neuroinflammation. PPAR signaling pathway mediates acrylamide-induced lipid metabolism disorder in the brain of zebrafish. Especially, chronic exposure to acrylamide dysregulates sphingolipid and phospholipid metabolism, which plays important roles in the development of anxiety and depression symptoms. In addition, acrylamide promotes lipid peroxidation and oxidation stress, which participate in cerebral neuroinflammation. Acrylamide dramatically increases the markers of lipid peroxidation, including (±)5-HETE, 11(S)-HETE, 5-oxoETE, and up-regulates the expression of proinflammatory lipid mediators such as (±)12-HETE and 14(S)-HDHA, indicating elevated cerebral inflammatory status after chronic exposure to acrylamide. Together, these results both epidemiologically and mechanistically provide strong evidence to unravel the mechanism of acrylamide-triggered anxiety and depression, and highlight the significance of reducing fried food consumption for mental health.

Gut microbiota: A new target for traditional Chinese medicine in the treatment of depression

ETHNIC PHARMACOLOGICAL RELEVANCE

The causes of depression are complex. Many factors are involved in its pathogenesis, including the individual's biological and social environment. Although numerous studies have reported that the gut microbiota plays a significant role in depression, drugs that regulate the gut microbiota to treat depression have not yet been comprehensively reviewed. At the same time, more and more attention has been paid to the characteristics of traditional Chinese medicine (TCM) in improving depression by regulating gut microbiota. In ancient times, fecal microbiota transplantation was recorded in TCM for the treatment of severe diseases. There are also records in Chinese ancient books about the use of TCM to adjust gut microbiota to treat diseases, which has opened up a unique research field in TCM. Therefore, this article focuses on the pharmacological effects, targets, and mechanisms of TCM in improving depression by mediating the influence of gut microbiota.

AIM OF THIS REVIEW

To summarize the role the gut microbiota plays in depression, highlight potential regulatory targets, and elucidate the anti-depression mechanisms of TCMs through regulation of the gut microbiota.

METHODS

A systematic review of 256 clinical trials and pharmaceutical studies published until June 2022 was conducted in eight electronic databases (Web of Science, PubMed, SciFinder, Research Gate, ScienceDirect, Google Scholar, Scopus, and China Knowledge Infrastructure), according to the implemented PRISMA criteria, using the search terms "traditional Chinese medicine," "depression," and "gut microbiota."

RESULTS

Numerous studies reported the effects of different gut bacteria on depression and that antidepressants work through the gut microbiota. TCM preparations based on compound Chinese medicine, the Chinese Materia Medica, and major bioactive components exerted antidepressant-like effects by improving levels of neurotransmitters, short-chain fatty acids, brain-derived neurotrophic factor, kynurenine, and cytokines via regulation of the gut microbiota.

CONCLUSION

This review summarized the anti-depression effects of TCM on the gut microbiota, providing evidence that TCMs are safe and effective in the treatment of depression and may provide a new therapeutic approach.

Aging accentuates decrease in tyrosine hydroxylase immunoreactivity associated with the increase in the motor impairment in a model of reserpine-induced parkinsonism

Parkinson's disease (PD) is an age-related neurodegenerative disorder characterized by progressive dopaminergic neuron loss. Animal models have been used to develop a better understanding of the pathophysiologic mechanisms of PD. However, these models are usually conducted with young animals diverging of the age of PD patients, suggesting a bias in translational science. Thus, the aim of the study was to evaluate the effect of the age on rats in a progressive parkinsonism model induced by reserpine (RES). Adult (6 - 8 month-old) or elderly (18 - 24 month-old) male rats were assigned to six groups: control-elderly (CTL-ELDERLY), reserpine-elderly (RES-ELDERLY), reserpine-elderly withdrawal (RES-ELDERLY WITHDRAWAL), control-adult (CTL-ADULT), reserpine-adult (RES-ADULT), and reserpine-adult withdrawal (RES-ADULT WITHDRAWAL). Animals received 15 injections every other day of RES (0.1 mg / kg) or vehicle during 30 days. Throughout treatment, animals were evaluated in the catalepsy test (every 48 h) and open field test (24 h after the second injection), and weight assessment (every 4 days) was also made. Upon completion of behavioral tests, rat brains were collected for tyrosine hydroxylase (TH) immunohistochemical analysis. Main results demonstrated that RES-treated animals spent more time in the catalepsy bar compared with control groups, moreover the RES-elderly group showed a longer catalepsy time compared with the RES-ADULT group. A shorter time from RES treatment to the development of symptoms was observed in the RES-ADULT group, compared with the RES-ELDERLY group. In addition, RES-induced weight loss in both RES-ELDERLY and RES-ADULT when compared with their corresponding controls. Cessation of RES treatment was followed by weight gain only in the RES-ADULT group. A significant decrease in TH-immunoreactive cells was observed in the substantia nigra pars compacta (SNpc) and dorsal striatum (STR) in the rats in both the RES-ADULT and RES-ELDERLY groups and in the ventral tegmental area in rats in the RES-ADULT group. Furthermore, TH immunoreactivity decrease was not reversible in SNpc and STR in the RES-ELDERLY. These results show that RES has an age-dependent effect in rats, suggesting a greater sensitivity of the dopaminergic pathway to RES with advancing age. These suggest that the RES rat model of parkinsonism can be useful in improving our knowledge on the effect of aging on neurodegeneration.

Physical exercise prevents behavioral alterations in a reserpine-treated zebrafish: A putative depression model

Major depressive disorder (MDD) has increasingly reached the world population with an expressive increase in recent years due to the COVID-19 pandemic. Here we used adult zebrafish (Danio rerio) as a model to verify the effects of reserpine on behavior and neurotransmitter levels. We observed an increase in the immobile time and time spent in the bottom zone of the tank in reserpine-exposed animals. The results demonstrated a decrease in distance traveled and velocity. Reserpine exposure did not induce changes in memory and social interaction compared to the control group. We also evaluated the influence of exposure to fluoxetine, a well-known antidepressant, on the behavior of reserpine-exposed animals. We observed a reversal of behavioral alterations caused by reserpine. To verify whether behavioral alterations in the putative depression model induced by reserpine could be prevented, the animals were subjected to physical exercise for 6 weeks. The results showed a protective effect of the physical exercise against the behavioral changes caused by reserpine in zebrafish. In addition, we observed a reduction in dopamine and serotonin levels and an increase in the 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the brain. Physical exercise was able to prevent the changes in dopamine and serotonin levels, reinforcing that the preventive effect promoted by physical exercise is related to the modulation of neurotransmitter levels. Our findings showed that reserpine was effective in the induction of a putative depression model in zebrafish and that physical exercise may be an alternative to prevent the effects induced by reserpine.

The food preservative sodium propionate induces hyperglycaemic state and neurological disorder in zebrafish

Propionate is an effective mould inhibitor widely used as a food preservative. In this study, we used zebrafish to explore the adverse effects of long-term exposure to low concentrations of sodium propionate and the underlying molecular mechanisms (from larvae to adult). When exposed for 3 months, we found that blood glucose, total cholesterol, and triglyceride levels increased, and zebrafish developed a hyperglycaemic state. New tank test results showed depression in zebrafish reduced 5-hydroxytryptamine levels in the brain and damaged the dopamine system. At the same time, the results of the color preference test showed that zebrafish had cognitive impairments. In addition, Hypothalamic-Pituitary-Adrenal axis analysis revealed abnormal gene expression, increased cortisol levels, and reduced glucocorticoid receptor mRNA levels, which were consistent with depressive behavior. We also observed abnormal transcription of inflammatory and apoptotic factors. Overall, we found that chronic exposure to sodium propionate induces depressive symptoms. This may be related to the activation of the HPA axis by the hyperglycaemic state, thereby inducing inflammation and disrupting the dopaminergic system. In summary, this study provides theoretical and technical support for the overlap of the emotional pathogenesis associated with diabetes.

Association of Chinese herbal medicine use with the depression risk among the long-term breast cancer survivors: A longitudinal follow-up study

Background

Breast cancer patients are at elevated risk of depression during treatment, thus provoking the chance of poor clinical outcomes. This retrospective cohort study aimed to investigate whether integrating Chinese herbal medicines citation(CHM) into conventional cancer therapy could decrease the risk of depression in the long-term breast cancer survivors.

Methods

A cohort of patients aged 20–70 years and with newly diagnosed breast cancer during 2000–2008 was identified from a nationwide claims database. In this study, we focused solely on survivors of breast cancer at least1 year after diagnosis. After one-to-one matching for age, sex, and baseline comorbidities, breast cancer patients who received (n = 1,450) and did not receive (n = 1,450) CHM treatment were enrolled. The incidence rate and hazard ratio citation(HR) for depression between the two groups was estimated at the end of 2012. A Cox proportional hazard model was constructed to examine the impact of the CHM use on the risk of depression.

Results

During the study period, the incidence rate of depression was significantly lower in the treated cohort than in the untreated cohort [8.57 compared with 11.01 per 1,000 person-years citation(PYs)], and the adjusted HR remained significant at 0.74 (95% CI 0.58–0.94) in a Cox proportional hazards regression model. The corresponding risk further decreasing to 43% among those using CHM for more than 1 year.

Conclusion

Finding from this investigation indicated that the lower risk of depression observed in breast cancer patients treated with CHM, suggesting that CHM treatment should be considered for disease management toward breast cancer. Yet, the optimal administered dose should be determined in further clinical trials.

Research progress on classical traditional chinese medicine formula xiaoyaosan in the treatment of depression

Depression is an emotional disorder that is problematic in psychiatry owing to its unclear etiology and unknown pathogenesis. Traditional Chinese medicine formulations such as Xiaoyaosan have been widely used throughout history to treat depression. In this review, we have focused on recent evidences elucidating the links between Xiaoyaosan and the treatment of depression. Data from animal and clinical studies, focusing on the pharmacological mechanisms, clinical applications, and effective materials that form the basis for the treatment of depression are presented and discussed. We found that the antidepressant effects of Xiaoyaosan are related to the effects of monoamine neurotransmitters, regulation of the hypothalamic-pituitary-adrenal axis, neuroplasticity, synaptic plasticity, inflammatory response, neuroprotection, brain-gut axis, regulation of intestinal microbiota, oxidative stress, and autophagy for reducing neuronal apoptosis. This review highlights the current evidence supporting the use of Xiaoyaosan as an antidepressant and provides an overview of the potential mechanisms involved.

Traditional herbal formula Jiao-tai-wan improves chronic restrain stress-induced depression-like behaviors in mice

OBJECTIVES

Jiao-tai-wan (JTW) has been often used to treat insomnia and diabetes mellitus. Recent studies found its antidepressant activity, but the related mechanism is not clear. This study is to evaluate the therapeutic effects of JTW on chronic restraint stress (CRS)-induced depression mice and explore the potential mechanisms.

METHODS

CRS was used to set up a depression model. Mice in different groups were treated with 0.9 % saline, JTW and fluoxetine. After the last day of CRS, the behavioral tests were conducted. The levels of neurotransmitters, inflammatory cytokines and HPA axis index were detected and the protein expressions of NLRP3 inflammasome complex were determined. H&E, NISSL, TUNEL and immunofluorescence staining were used to observe histopathological changes and the activation of microglia and astrocytes. The potential mechanisms were explored via network pharmacology and verified by Western blot.

RESULTS

The assessment of liver and kidney function showed that JTW was non-toxic. Behavioral tests proved that JTW can effectively ameliorate depression-like symptoms in CRS mice, which may be related to the inhibition of NLRP3 inflammasome activation. JTW can also improve the inflammatory state and HPA axis hyperactivity in mice, and has a protective effect on CRS-induced hippocampal neurons damage. The network pharmacology analysis and the results of Western blot suggested that the antidepressant effects of JTW may be related to the MAPK signaling pathway.

CONCLUSION

Our findings indicated that JTW may exert antidepressant effects in CRS-induced mice by inhibiting NLRP3 inflammasome activation and improving inflammatory state, and MAPK signaling pathway may also be involved.

Ameliorative effect of Gastrodia elata Blume extracts on depression in zebrafish and cellular models through modulating reticulon 4 receptors and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Gastrodia elata Blume (G. elata), a traditional Chinese herb, known as "Tian Ma", is widely used as a common medicine and diet ingredient for treating or preventing neurological disorders for thousands of years in China. However, the anti-depressant effect of G. elata and the underlying mechanism have not been fully evaluated.

AIM OF THE STUDY

The study is aimed to investigate the anti-depressant effect and the molecular mechanism of G. elata in vitro and in vivo using PC12 cells and zebrafish model, respectively.

MATERIAL AND METHODS

Network pharmacology was performed to explore the potential active ingredients and action targets of G. elata Blume extracts (GBE) against depression. The cell viability and proliferation were determined by MTT and EdU assay, respectively. TUNEL assay was used to examine the anti-apoptotic effect of GBE. Immunofluorescence and Western blot were used to detect the protein expression level. In addition, novel tank diving test was used to investigate the anti-depressant effect in zebrafish depression model. RT-PCR was used to analyze the mRNA expression levels of genes.

RESULTS

G. elata against depression on the reticulon 4 receptors (RTN4R) and apoptosis-related targets, which were predicted by network pharmacology. Furthermore, GBE enhanced cell viability and inhibited the apoptosis in PC12 cells against CORT treatment. GBE relieved depression-like symptoms in adult zebrafish, included increase of exploratory behavior and regulation of depression related genes. Mechanism studies showed that the GBE inhibited the expression of RTN4R-related and apoptosis-related genes.

CONCLUSION

Our studies show the ameliorative effect of G. elata against depression. The mechanism may be associated with the inhibition of RTN4R-related and apoptosis pathways.

Effect of aerobic exercise as a treatment on type 2 diabetes mellitus with depression-like behavior zebrafish

BACKGROUND

Depression is the most known complication of type 2 diabetes mellitus (T2DM). Aerobic exercise improves glycemic control in T2DM, although the underlying mechanisms of comorbid depression-like behaviors in T2DM have not yet been fully elucidated.

METHODS

120 zebrafish were randomly assigned to four groups: Control, T2DM, T2DM + metformin, and T2DM + aerobic exercise. Then, all animals except the control group were fed with high glucose fairy shrimp (~40 g/kg/day) and exposed reserpine (40 μg/ml for 20 min) for 10 days. Here, behavioral tests were used for model verification. Following the verification, all groups were treated as before. Additionally, the T2DM + metformin group received metformin (~10.6 mg/kg/day) at the same time, while the T2DM + aerobic exercise group received aerobic exercise 30 min/day. Finally, blood glucose and behavioral tests, as well as protein and molecular levels were determined at Day 11 and 12.

RESULTS

Aerobic exercise alleviated depressive-like behavior and enhanced the levels of antidepressant biomarkers (NE, 5-HIAA) in zebrafish after 10 consecutive days of exercise. Additionally, 10 consecutive days of aerobic exercise decreased the levels of inflammatory biomarkers (IFN-γ, IL-1, IL-4) and depressive biomarkers (cortisol). Meanwhile, it also aided in the reduction of CD11b, IL-6, IL-6R, and caspase-3 expression to combat the neuroinflammation induced by T2DM, mediated the BDNF-TrkB pathway, and increased Bcl-2/Bax levels.

CONCLUSION

Given the remarkable similarity in neurochemistry between humans and zebrafish, this study supports the effectiveness of aerobic exercise as clinical guidance in preventing and treating T2DM complicated with depression.

Towards translational modeling of behavioral despair and its treatment in zebrafish

Depression is a widespread and severely debilitating neuropsychiatric disorder whose key clinical symptoms include low mood, anhedonia and despair (the inability or unwillingness to overcome stressors). Experimental animal models are widely used to improve our mechanistic understanding of depression pathogenesis, and to develop novel antidepressant therapies. In rodents, various experimental models of 'behavioral despair' have already been developed and rigorously validated. Complementing rodent studies, the zebrafish (Danio rerio) is emerging as a powerful model organism to assess pathobiological mechanisms of depression and other related affective disorders. Here, we critically discuss the developing potential and important translational implications of zebrafish models for studying despair and its mechanisms, and the utility of such aquatic models for antidepressant drug screening.

General Use of Chinese Herbal Products among Female Patients with Mastitis in Taiwan

Objectives

Little information is available regarding the use of Chinese herbal medicine to treat mastitis. This study evaluated the prescription patterns of Chinese herbal medicine products in women with mastitis in Taiwan.

Design

This is a population-based cross-sectional study. Setting. 8,531 women aged 20–49 years, who received a diagnosis of mastitis between 2004 and 2013, were identified from the Longitudinal Health Insurance Database in Taiwan. We collected data on demographic characteristics, including age, monthly insurance premium, and urbanization level. The ten most Chinese herbal medicines prescribed for mastitis were assessed, including frequency, percentage, average daily dose, and average duration of prescription. Main outcome measures. We analysed the ten most single Chinese herbs and Chinese herbal formulae prescribed for mastitis.

Results

Overall, 437 (5.1%) women received Chinese herbal medicine to treat mastitis. Mai Men Dong (Ophiopogon japonicus (Thunb.) Ker Gawl.; 22.3%), Pu Gong Yin (Taraxacum mongolicum Hand.-Mazz.; 7.8%), and Wang Bu Liu Xing (Vaccaria hispanica (Mill.) Rauschert; 3.5%) were three of the most commonly prescribed single Chinese herbs for mastitis. Xian-Fang-Huo-Ming-Yin (18.2%), Jia-Wei-Xiao-Yao-San (9.1%), and Chai-Hu-Shu-Gan-San (8.4%) were three of the most commonly prescribed Chinese herbal formulae.

Conclusion

Xian-Fang-Huo-Ming-Yin can clear heat, detoxify body, alleviate swelling, activate blood, and relieve pain. It was the most frequently prescribed Chinese herbal formula in patients with mastitis.

Fluorene-9-bisphenol exposure decreases locomotor activity and induces lipid-metabolism disorders by impairing fatty acid oxidation in zebrafish

AIMS

Fluorene-9-bisphenol (BHPF), as a substitute for bisphenol A, is used in many industries in daily life. Many studies have clarified its effects as an endocrine disruptor on organisms, but its effect on lipid metabolism of zebrafish larvae is not clear. Patients with non-alcoholic fatty liver disease (NAFLD) are more susceptible to external pollutants. It is not clear how BHPF perturbs lipid metabolism or promotes NAFLD progression.

MAIN METHODS

We explored the biological effects of BHPF on locomotor activity, inflammatory response, endoplasmic reticulum (ER) stress and lipid metabolism in zebrafish, especially in the mechanism of lipid homeostasis disorder. In addition, the role of BHPF in the progression of non-alcoholic fatty liver disease (NAFLD) was further explored.

KEY FINDINGS

We found that high concentration (100 nmol/L) BHPF caused retarded growth, mild lipid accumulation and reduced the locomotive activity of zebrafish larvae, accompanied by a decrease in endogenous cortisol level. At the same time, it caused the full activation of inflammation and ER stress. Rescue experiments by 25(OH)D₃ demonstrated that high concentration of BHPF caused defects in 1,25(OH)₂D₃ metabolic pathway through downregulation of cyp2r1, which further damaged pgc1a-mediated fatty acid oxidation and mitochondrial function, resulting in lipid accumulation. In summary, exposure to BHPF could damage lipid homeostasis and worsen the diet-induced NAFLD.

SIGNIFICANCE

Our findings provide new insights into the role of BHPF in development of overweight and obesity and also improve understanding of its toxicological mechanism. Our results play a warning role in the administration of environmental pollutants.

Elaborate the Mechanism of Ancient Classic Prescriptions (Erzhi Formula) in Reversing GIOP by Network Pharmacology Coupled with Zebrafish Verification

Osteoporosis is a degenerative disease that endangers human health. At present, chemical drugs used for osteoporosis have serious side effects. Therefore, it is valuable to search herbs with high safety and good curative effect in antiosteoporosis. Erzhi formula (EZF), an ancient classic compound, has been reported to have a beneficial effect in antiosteoporosis, but its mechanism is unclear. In this paper, the active compounds of EZF were found in Systems Pharmacology Database, and gene targets related to osteoporosis were obtained in GeneCards. The GO functional and KEGG pathway enrichment analysis were performed by Metascape. The network of “components-targets-signal pathway” was constructed by Cytoscape. Next, molecular docking between the active components and hub genes related to the PI3K-Akt signaling pathway was conducted by Autodock. In the verification experiment, the zebrafish induced by prednisolone (PNSL) was used to reproduce glucocorticoid-induced osteoporosis (GIOP) model, and then the reversal effects of EZF were systematically evaluated according to the behavior, skull staining area, bone mineralization area (BMA), average optical density (AOD), and cumulative optical density (COD). Finally, it was shown that 24 components in EZF could regulate 39 common gene targets to exert antiosteoporosis effect. Besides, the main regulatory mechanisms of EZF were 4 signaling pathways: PI3K-Akt, JAK-STAT, AGE-RAGE, and cancer pathway. In PI3K-Akt signaling pathway, wedelolactone, dimethyl wedelolactone, specnuezhenide, ursolic acid, acacetin, beta-sitosterol, apigenin, and kaempferol can bind tightly with EGF, IL-2, and IL-4 genes. Compared with the model group, the moving distance, swimming speed, and cumulative swimming time of zebrafish in EZF group were significantly increased (P < 0.05). Meanwhile, the BMA and COD of zebrafish were significantly improved after the intervention of EZF (P < 0.05). In summary, the 24 components of EZF exert their antiosteoporosis effects by regulating 39 related gene targets, among which the PI3K signaling pathway is crucial. EZF can promote bone formation and reversed GIOP through “multicomponent/multitarget/multipathway” and the medium dose of EZF may be the most suitable concentration for the treatment of GIOP in zebrafish model.

Zebrafish Behavioral Phenomics Links Artificial Sweetener Aspartame to Behavioral Toxicity and Neurotransmitter Homeostasis

Artificial sweeteners (ASs) are extensively used as food additives in drinks and beverages to lower calorie intake and prevent lifestyle diseases such as obesity. Although clinical and epidemiological data revealed the link between the chronic overconsumption of ASs and adverse health effects, there still exist controversies over the potential adverse neural toxic effect of ASs such as aspartame (APM), with acceptable daily intake (ADI) for a long time, on human health. In addition, whether APM and its metabolites are neurotoxic remains debatable due to a lack of data from an animal experiment or clinical investigation. Herein, to fully describe the potential neurological effect of APM, adult zebrafish served as the animal model to assess neurophysiological alteration induced by APM exposure within the range of the ADI (1, 10, and 100 mg/L) for 2 months. A cohort of standardized neurobehavioral phenotyping assays was conducted, including light/dark preference tests (LDP), novel tank diving tests, novel object recognition tests, social interaction tests, and color preference tests. For instance, in the LDP test, saccharin remarkably decreased the swimming time of zebrafish in the DARK part from 111 ± 10.8 (control group) to 72.2 ± 11.4 (100 mg/L groups). Besides, brain chemistry involved in the alteration of total neurotransmitters was determined by LC-MS/MS to confirm the behavioral results. Overall, current research studies revealed that APM within the range of the ADI altered the total behavioral profiles of zebrafish and disturbed the homeostasis of neurotransmitters in the brain. The present study has established a set of experimental paradigms, revealing the standardized procedure of using adult zebrafish to determine the neural activity or toxicity of AS molecules phenotypically. Zebrafish behavioral phenotyping methods, which were characterized by a cohort of behavioral fingerprints, can link the phenotypical alteration to changes in neurotransmitters in the brain, so as to provide a predictive reference for the further exploration of the molecular mechanism of phenotypic changes induced by ASs.

Towards Modeling Anhedonia and Its Treatment in Zebrafish

Mood disorders, especially depression, are a major cause of human disability. The loss of pleasure (anhedonia) is a common, severely debilitating symptom of clinical depression. Experimental animal models are widely used to better understand depression pathogenesis and to develop novel antidepressant therapies. In rodents, various experimental models of anhedonia have already been developed and extensively validated. Complementing rodent studies, the zebrafish (Danio rerio) is emerging as a powerful model organism to assess pathobiological mechanisms of affective disorders, including depression. Here, we critically discuss the potential of zebrafish for modeling anhedonia and studying its molecular mechanisms and translational implications.

Association between common cardiovascular drugs and depression

Objective:

Cardiovascular diseases are associated with an increased risk of depression, but it remains unclear whether treatment with cardiovascular agents decreases or increases this risk. The effects of drugs on individual usage are also often unknown. This review aimed to examine the correlation between depression and common cardiovascular drugs, develop more potent interventions for depression in cardiovascular patients, and further research on the bio-behavioural mechanisms linking cardiovascular drugs to depression.

Data sources:

The data in this review were obtained from articles included in PubMed, EMBASE, and Web of Science.

Study selection:

Clinical trials, observational studies, review literature, and guidelines about depression and cardiovascular drugs were selected for the article.

Results:

We systematically investigated whether the seven most used cardiovascular drugs were associated with altered risk of incident depression in this literature review. Statins have been proven to have antidepressant effects. Some studies believe angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin receptor blocker (ARB) can exert an antidepressant influence by acting on the renin-angiotensin system, but further clinical trials are needed to confirm this. Beta-blockers have previously been associated with depression, but the current study found no significant association between beta blockers and the risk of depression. Aspirin may have antidepressant effects by suppressing the immune response, but its role as an antidepressant remains controversial. calcium channel blockers (CCBs) can regulate nerve signal transduction by adjusting calcium channels, but whether this effect is beneficial or harmful to depression remains unclear. Finally, some cases have reported that nitrates and diuretics are associated with depression, but the current clinical evidence is insufficient.

Conclusions:

Statins have been proven to have antidepressant effect, and the antidepressant effects of ACEIs/ARB and aspirin are still controversial. CCBs are associated with depression, but it is unclear whether it is beneficial or harmful. No association has been found with β-blockers, diuretics, and nitrates.

Application and advantages of zebrafish model in the study of neurovascular unit

The concept of "Neurovascular Unit" (NVU) was put forward, so that the research goal of Central Nervous System (CNS) diseases gradually transitioned from a single neuron to the structural and functional integrity of the NVU. Zebrafish has the advantages of high homology with human genes, strong reproductive capacity and visualization of neural circuits, so it has become an emerging model organism for NVU research and has been applied to a variety of CNS diseases. Based on CNKI (https://www.cnki.net/) and PubMed (https://pubmed.ncbi.nlm.nih.gov/about/) databases, the author of this article sorted out the relevant literature, analyzed the construction of a zebrafish model of various CNS diseases，and the use of diagrams showed the application of zebrafish in the NVU, revealed its relationship, which would provide new methods and references for the treatment and research of CNS diseases.

A Reliable High-Throughput Screening Model for Antidepressant

Depression is the most frequent affective disorder and is the leading cause of disability worldwide. In order to screen antidepressants and explore molecular mechanisms, a variety of animal models were used in experiments, but there is no reliable high-throughput screening method. Zebrafish is a common model organism for mental illness such as depression. In our research, we established chronic unpredictable mild stress (CUMS) models in C57BL/6 mice and zebrafish; the similarities in behavior and pathology suggest that zebrafish can replace rodents as high-throughput screening organisms. Stress mice (ip., 1 mg/kg/d, 3 days) and zebrafish (10 mg/L, 20 min) were treated with reserpine. As a result, reserpine caused depression-like behavior in mice, which was consistent with the results of the CUMS mice model. Additionally, reserpine reduced the locomotor ability and exploratory behavior of zebrafish, which was consistent with the results of the CUMS zebrafish model. Further analysis of the metabolic differences showed that the reserpine-induced zebrafish depression model was similar to the reserpine mice model and the CUMS mice model in the tyrosine metabolism pathway. The above results showed that the reserpine-induced depression zebrafish model was similar to the CUMS model from phenotype to internal metabolic changes and can replace the CUMS model for antidepressants screening. Moreover, the results from this model were obtained in a short time, which can shorten the cycle of drug screening and achieve high-throughput screening. Therefore, we believe it is a reliable high-throughput screening model.

Anticancer Effect of ERM210 on Liver Cancer Cells Through ROS/Mitochondria-dependent Apoptosis Signaling Pathways

BACKGROUND/AIM

Asian Traditional medicines are renowned for their antitumor properties and are efficacious in the clinical treatment of various cancer types. ERM210 is a Korean traditional medicine comprising nine types of medicinal plants. In the present study, we examined the pro-apoptotic effect and molecular mechanisms of the effects of ERM210 on HepG2 liver cancer cells.

MATERIALS AND METHODS

The cytotoxicity of ERM210 on HepG2 cells was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and wound-healing assays, and apoptosis and signaling pathways by fluorescence microscopy flow cytometry and western blotting.

RESULTS

ERM210 significantly impaired HepG2 cell viability and enhanced mitochondria-dependent cellular apoptosis in a time- and dose-dependent manner by up-regulating the expression of caspases 3, 7 and 9, and of BCL2 apoptosis regulator (BCL2)-associated X, apoptosis regulator (BAX) proteins, whilst down-regulating that of BCL2 protein. Furthermore, ERM210 treatment increased accumulation of cellular and mitochondrial reactive oxygen species (ROS) and significantly inhibited cell migration. Additionally, all these phenomena were reversed by treating with the ROS scavenger N-acetylcysteine. The analysis of signaling proteins revealed that ERM210 significantly up-regulated the phosphorylation of ROS-dependent mitogen-activated protein kinases (p38, extracellular-regulated kinase, and c-Jun N-terminal kinase in HepG2 liver cancer cells.

CONCLUSION

ERM210 exerts anticancer effects in HepG2 liver cancer cells by up-regulating ROS/mitochondria-dependent apoptosis signaling, providing new insight into the possibility of employing this traditional medicine for the clinical treatment of liver cancer.

Antidepressant and Anxiolytic-Like Effects of the Stem Bark Extract of Fraxinus rhynchophylla Hance and Its Components in a Mouse Model of Depressive-Like Disorder Induced by Reserpine Administration

There is an urgent need to find antidepressants that can be administered for long periods without inducing severe side effects to replace conventional antidepressants that control monoamine levels, such as tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), and selective serotonin reuptake inhibitors (SSRI). We sought to determine the antidepressant effects of Fraxinus rhynchophylla Hance (F. rhynchophylla Hance, FX) and its components on a reserpine-induced mouse model. One hour after oral administration of FX (30, 50, and 100 mg/kg), esculin (50 mg/kg), esculetin (50 mg/kg), fraxin (50 mg/kg), and fluoxetine (20 mg/kg), reserpine was delivered intraperitoneally to mice. Behavioral experiments were conducted to measure anxiety and depressive-like behaviors after 10 days of administration. FX and its components increased the number of entries into the center of an open field as well as distance traveled within it and decreased immobility duration in the forced swim and tail suspension tests. Reserpine-induced increases in plasma corticosterone concentrations were attenuated by the administration of FX and its components, which were also found to decrease the reserpine-induced enhancement of mRNA levels of interleukin (IL)-12 p40, IL-6, and tumor necrosis factor (TNF)-α, pro-inflammatory cytokines. Finally, the diminished expressions of hippocampal phosphorylated cAMP response element-binding protein (pCREB) and brain-derived neurotrophic factor (BDNF) by reserpine were increased by FX and its components. Our results suggest that FX and its components regulate anxiety and depressive-like behaviors through stress hormones, immune regulation, and the activation of neuroprotective mechanisms, further supporting the potential of FX and its components as antidepressants.

Swimming in the maze: An overview of maze apparatuses and protocols to assess zebrafish behavior

Most preclinical behavioral assays use rodents as model animals, leaving room for species-specific biases that could be avoided by an expanded cross-species approach. In this context, zebrafish emerges as an alternative model organism to study neurobiological mechanisms of anxiety, preference, learning, and memory, as well as other phenotypes with relevance to neuropsychiatric disorders. In recent years, several zebrafish studies using different types of mazes have been published. However, the protocols and apparatuses' shapes and dimensions vary widely in the literature. This variation may puzzle researchers attempting to implement maze behavioral assays and challenges the reproducibility across institutions. This review aims to provide an overview of the behavioral paradigms assessed in different types of mazes in zebrafish reported in the last couple of decades. Also, this review aims to contribute to a better characterization of multi-behavioral assessment in zebrafish.

Studying CNS effects of Traditional Chinese Medicine using zebrafish models

ETHNOPHARMACOLOGICAL RELEVANCE

Although Traditional Chinese Medicine (TCM) has a millennia-long history of treating human brain disorders, its complex multi-target mechanisms of action remain poorly understood. Animal models are currently widely used to probe the effects of various TCMs on brain and behavior. The zebrafish (Danio rerio) has recently emerged as a novel vertebrate model organism for neuroscience research, and is increasingly applied for CNS drug screening and development.

AIM OF THE STUDY

As zebrafish models are only beginning to be applied to studying TCM, we aim to provide a comprehensive review of the TCM effects on brain and behavior in this fish model species.

MATERIALS AND METHODS

A comprehensive search of published literature was conducted using biomedical databases (Web of Science, Pubmed, Sciencedirect, Google Scholar and China National Knowledge Internet, CNKI), with key search words zebrafish, brain, Traditional Chinese Medicine, herbs, CNS, behavior.

RESULTS

We recognize the developing utility of zebrafish for studying TCM, as well as outline the existing model limitations, problems and challenges, as well as future directions of research in this field.

CONCLUSIONS

We demonstrate the growing value of zebrafish models for studying TCM, aiming to improve our understanding of TCM' therapeutic mechanisms and potential in treating brain disorders.

Exposure to silver impairs learning and social behaviors in adult zebrafish

Silver and silver nanoparticles are used in several consumer products, particularly sterilizing agents. Ag⁺ released from the particles causes physiological damages of aquatic organisms. However, the effects of silver on neural and behavioral functions of fish remain unclear. Here, we used zebrafish as a model to investigate the impacts of silver on social, learning and memory behaviors in teleost. Adult zebrafish showed mortality rates of 12.875% and 100% on 72 h exposure to 30 and ≥ 50 ppb of silver nitrate, respectively. Silver accumulation in the brain increased on exposure to 10 and 30 ppb of AgNO₃. The physical fitness of the zebrafish, measured by novel tank diving test and swimming performance, decreased after 72 h incubation in 30 ppb of AgNO₃. Exposure to 10 ppb of AgNO₃ impaired social preference, social recognition, learning, and memory, but did not affect anxiety level, aggressiveness, and shoaling behavior. In situ hybridization of c-fos mRNA showed that AgNO₃ treatment decreased neural activity in the brain areas crucial for learning, memory, and social behaviors, including the medial and dorsal zones of the dorsal telencephalic area. In conclusion, 72 h exposure to AgNO₃ in a sublethal level impaired learning and social behaviors, indicating neurotoxicity in adult zebrafish.

Color as an important biological variable in zebrafish models: Implications for translational neurobehavioral research

Color is an important environmental factor that in multiple ways affects human and animal behavior and physiology. Widely used in neuroscience research, various experimental (animal) models may help improve our understanding of how different colors impact brain and behavioral processes. Complementing laboratory rodents, the zebrafish (Danio rerio) is rapidly emerging as an important novel model species to explore complex neurobehavioral processes. The growing utility of zebrafish in biomedicine makes it timely to consider the role of colors in their behavioral and physiological responses. Here, we summarize mounting evidence implicating colors as a critical variable in zebrafish models and neurobehavioral traits, with a particular relevance to CNS disease modeling, genetic and pharmacological modulation, as well as environmental enrichment and animal welfare. We also discuss the growing value of zebrafish models to study color neurobiology and color-related neurobehavioral phenomics, and outline future directions of research in this field.

Duplicated dnmt3aa and dnmt3ab DNA Methyltransferase Genes Play Essential and Non-Overlapped Functions on Modulating Behavioral Control in Zebrafish

DNA methylation plays several roles in regulating neuronal proliferation, differentiation, and physiological functions. The major de novo methyltransferase, DNMT3, controls the DNA methylation pattern in neurons according to environmental stimulations and behavioral regulations. Previous studies demonstrated that knockout of Dnmt3 induced mouse anxiety; however, controversial results showed that activation of Dnmt3 causes anxiolytic behavior. Thus, an alternative animal model to clarify Dnmt3 on modulating behavior is crucial. Therefore, we aimed to establish a zebrafish (Danio rerio) model to clarify the function of dnmt3 on fish behavior by behavioral endpoint analyses. We evaluated the behaviors of the wild type, dnmt3aa, and dnmt3ab knockout (KO) fish by the novel tank, mirror biting, predator avoidance, social interaction, shoaling, circadian rhythm locomotor activity, color preference, and short-term memory tests. The results indicated that the dnmt3aa KO fish possessed abnormal exploratory behaviors and less fear response to the predator. On the other hand, dnmt3ab KO fish displayed less aggression, fear response to the predator, and interests to interact with their conspecifics, loosen shoaling formation, and dysregulated color preference index ranking. Furthermore, both knockout fishes showed higher locomotion activity during the night cycle, which is a sign of anxiety. However, changes in some neurotransmitter levels were observed in the mutant fishes. Lastly, whole-genome DNA methylation sequencing demonstrates a potential network of Dnmt3a proteins that is responsive to behavioral alterations. To sum up, the results suggested that the dnmt3aa KO or dnmt3ab KO fish display anxiety symptoms, which supported the idea that Dnmt3 modulates the function involved in emotional control, social interaction, and cognition.

Polydatin alleviates parkinsonism in MPTP-model mice by enhancing glycolysis in dopaminergic neurons

Parkinson's disease (PD) is a common neurodegenerative disease. Damage to energy metabolism and reduced adenosine triphosphate (ATP) levels in dopaminergic neurons are common features of PD. Previous studies suggested that the occurrence of PD often affects glucose metabolism and ATP production in the brain, and increased glycolysis or ATP production protects dopaminergic neuronal degeneration in the brain of PD patients. These systems may provide new potential therapeutic targets for the prevention of PD. The present study investigated the inhibitory action of polydatin (PLD) on early dopaminergic neuronal degeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The results showed that PLD protected against MPTP-induced early dopaminergic neuronal degeneration. PLD reduced the MPTP-induced loss of dopaminergic neurons in substantia nigra and striatum, inhibited the occurrence of neural apoptosis, and restored motor function in mice. PLD also increased the continuous activity duration and rhythm amplitude in mice during the circadian activity test. PLD improved glucose metabolism in the brain and restored ATP production levels. These observations suggest that PLD attenuates MPTP-induced early PD-like symptoms, and its mechanism of action may be associated with the promotion of glucose metabolism in neurons.

Method Standardization for Conducting Innate Color Preference Studies in Different Zebrafish Strains

The zebrafish has a tetrachromatic vision that is able to distinguish ultraviolet (UV) and visible wavelengths. Recently, zebrafish color preferences have gained much attention because of the easy setup of the instrument and its usefulness to screen behavior-linked stimuli. However, several published papers dealing with zebrafish color preferences have contradicting results that underscore the importance of method standardization in this field. Different laboratories may report different results because of variations in light source, color intensity, and other parameters such as age, gender, container size, and strain of fish. In this study, we aim to standardize the color preference test in zebrafish by measuring light source position, light intensity, gender, age, animal size to space ratio, and animal strain. Our results showed that color preferences for zebrafish are affected by light position, age, strain, and social interaction of the fish, but not affected by fish gender. We validated that ethanol can significantly induce color preference alteration in zebrafish which may be related to anxiety and depression. We also explored the potential use of the optimized method to examine color preference ranking and index differences in various zebrafish strains and species, such as the tiger barb and glass catfish. In conclusion, zebrafish color preference screening is a powerful tool for high-throughput neuropharmacological applications and the standardized protocol established in this study provides a useful reference for the zebrafish research community.

Potential effect of herbal antidepressants on cognitive deficit: Pharmacological activity and possible molecular mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

Cognitive symptom is a "core" symptom of major depressive disorder (MDD) patients with clear deficit in memory, social and occupational function, and may persist during the remitting phase. Therefore, the remission of cognitive symptom has been considered as one of the main objectives in the treatment of MDD. Herbal antidepressants have been used to treat MDD, and there has been great advances in the understanding of the ability of these herbs to improve cognitive deficit linked to brain injury and various diseases including depression, Alzheimer disease, diabetes and age-related disorders. This systematic review summarizes the evidence from preclinical studies and clinical trials of herbal antidepressants with positive effects on cognitive deficit. The potential mechanisms by which herbal antidepressants prevent cognitive deficit are also reviewed. This review will facilitate further research and applications.

MATERIALS AND METHODS

We conducted an open-ended, English restricted search of MEDLINE (PubMed), Web of Science and Scopus for all available articles published or online before 31 December 2019, using terms pertaining to medical herb/phytomedicine/phytochemical/Chinese medicine and depression/major depressive disorder/antidepressant and/or cognitive impairment/cognitive deficit/cognitive dysfunction.

RESULTS

7 prescriptions, more than 30 individual herbs and 50 phytochemicals from China, Japan, Korea and India with positive effects on the depressive state and cognitive deficit are reviewed herein. The evidence from preclinical studies and clinical trials proves that these herbal antidepressants exhibit positive effects on one or more aspects of cognitive defect including spatial, episodic, aversive, and short- and long-term memory. The action mode of the improvement of cognitive deficit by these herbal antidepressants is mediated mainly through two pathways. One pathway is to promote hippocampal neurogenesis through activating brain derived neurotrophic factor-tropomyosin-related kinase B signaling. The other pathway is to prevent neuronal apoptosis through the inhibition of neuro-inflammation and neuro-oxidation.

CONCLUSION

These herbal antidepressants, having potential therapy for cognitive deficit, may prevent pathological processes of neurodegenerative diseases. Furthermore, these herbal medicines should provide a treasure trove, which will accelerate the development of new antidepressants that can effectively improve cognitive symptom in MDD. Studies on their molecular mechanisms may provide more potential targets and therapeutic approaches for new drug discovery.

In Silico Studies and In Vivo MAOA Inhibitory Activity of Coumarins Isolated from Angelica archangelica Extract: An Approach toward Antidepressant Activity

The current investigation was aimed at in vivo MAO_A inhibitory activity of coumarins angelicin, bergapten, and scopoletin isolated from the roots of Angelica archangelica. The isolated compounds were screened for MAO_A (pdb ID 2Z5y) binding through molecular docking studies. The molecular docking results displayed that bergapten has a maximum affinity for MAO_A, followed by angelicin and scopoletin. In silico prediction of physicochemical parameters indicated that maximum blood-brain barrier (BBB) permeability was observed with angelicin (2.3), followed by bergapten (2.0) and least with scopoletin (0.644). In consonance to the results of molecular docking studies, appreciable in vivo antidepressant activity of angelicin and bergaptan was observed over the mouse model of reserpine-induced depression. The modulation of MAO_A in the antidepressant effect of extract and its isolated fractions was also determined. Biochemical examination of the brain tissue indicated that bergapten has maximum MAO_A inhibitory activity while scopoletin fails to inhibit brain MAO_A.

A Novel Function of the Lysophosphatidic Acid Receptor 3 (LPAR3) Gene in Zebrafish on Modulating Anxiety, Circadian Rhythm Locomotor Activity, and Short-Term Memory

Lysophosphatidic acid (LPA) is a small lysophospholipid molecule that activates multiple cellular functions through pathways with G-protein-coupled receptors. So far, six LPA receptors (LPAR1 to LPAR6) have been discovered and each one of them can connect to the downstream cell message-transmitting network. A previous study demonstrated that LPA receptors found in blood-producing stem cells can enhance erythropoietic processes through the activation of LPAR3. In the current study, newly discovered functions of LPAR3 were identified through extensive behavioral tests in lpar3 knockout (KO) zebrafish. It was found that the adult lpar3 KO zebrafish display an abnormal movement orientation and altered exploratory behavior compared to that of the control group in the three-dimensional locomotor and novel tank tests, respectively. Furthermore, consistent with those results, in the circadian rhythm locomotor activity test, the lpar3 KO zebrafish showed a lower level of angular velocity and average speed during the light cycles, indicating an hyperactivity-like behavior. In addition, the mutant fish also exhibited considerably higher locomotor activity during the dark cycle. Supporting those findings, this phenomenon was also displayed in the lpar3 KO zebrafish larvae. Furthermore, several important behavior alterations were also observed in the adult lpar3 KO fish, including a lower degree of aggression, less interest in conspecific social interaction, and looser shoal formation. However, there was no significant difference regarding the predator avoidance behavior between the mutant and the control fish. In addition, lpar3 KO zebrafish displayed memory deficiency in the passive avoidance test. These in vivo results support for the first time that the lpar3 gene plays a novel role in modulating behaviors of anxiety, aggression, social interaction, circadian rhythm locomotor activity, and memory retention in zebrafish.

Zebrafish neuro-behavioral profiles altered by acesulfame (ACE) within the range of "no observed effect concentrations (NOECs)"

Recently, artificial sweeteners have received widespread attention as the emerging environmental pollutants, among which, acesulfame (ACE) is ubiquitously present and extremely persistent in the ecosystem. Although the environmental behavior of ACE has already been well studied, its chronic eco-toxicological effects on aquatic organisms are rarely reported. Thus, more researches should be performed to determine the concentration which exerted the observable toxicological effect. Herein, we examined neuro-behavioral effects of ACE at 1, 10 and 100 mg/L on adult zebrafish via performing the behavioral test batteries including light/dark preference test, novel tank diving test, novel object exploration test, social preference test and colour-enhanced CPP test. In addition, in order to fully phenotype the behavioral alteration induced by ACE, we applied the techniques deriving from behavioral phenomics to analyze and interpret the big data from a large number of behavioral variables. Furthermore, the alterations of neurotransmitter in brain were also assayed to confirm the behavioral results. We found that ACE within the concentration range of No Observed Effect Concentrations (NOECs) had remarkably altered the neuro-behavioral profiles: altered the preference for light/dark, reduced the exploration ability of zebrafish in the novel tank and novel object exploration test, affected the group preference of zebrafish, changed the colour preference, learning and memory ability of zebrafish and disturbed the quantitative patterns of neurotransmitter in brain. As a result, this research can offer a reference for readjusting the NOECs of ACE and assessing neurotoxicity of artificial sweeteners.

The zebrafish tail immobilization (ZTI) test as a new tool to assess stress-related behavior and a potential screen for drugs affecting despair-like states

BACKGROUND

Affective disorders, especially depression and anxiety, are highly prevalent, debilitating mental illnesses. Animal experimental models are a valuable tool in translational affective neuroscience research. A hallmark phenotype of clinical and experimental depression, the learned helplessness, has become a key target for 'behavioral despair'-based animal models of depression. The zebrafish (Danio rerio) has recently emerged as a promising novel organism for affective disease modeling and CNS drug screening. Despite being widely used to assess stress and anxiety-like behaviors, there are presently no clear-cut despair-like models in zebrafish.

NEW METHOD

Here, we introduce a novel behavioral paradigm, the zebrafish tail immobilization (ZTI) test, as a potential tool to assess zebrafish despair-like behavior. Conceptually similar to rodent 'despair' models, the ZTI protocol involves immobilizing the caudal half of the fish body for 5 min, leaving the cranial part to move freely, suspended vertically in a small beaker with water.

RESULTS

To validate this model, we used exposure to low-voltage electric shock, alarm pheromone, selected antidepressants (sertraline and amitriptyline) and an anxiolytic drug benzodiazepine (phenazepam), assessing the number of mobility episodes, time spent 'moving', total distance moved and other activity measures of the cranial part of the body, using video-tracking. Both electric shock and alarm pheromone decreased zebrafish activity in this test, antidepressants increased it, and phenazepam was inactive. Furthermore, a 5-min ZTI exposure increased serotonin turnover, elevating the 5-hydroxyindoleacetic acid/serotonin ratio in zebrafish brain, while electric shock prior to ZTI elevated both this and the 3,4-dihydroxyphenylacetic acid/dopamine ratios. In contrast, preexposure to antidepressants sertraline and amitriptyline lowered both ratios, compared to the ZTI test-exposed fish.

COMPARISON WITH EXISTINGMETHOD(S)

The ZTI test is the first despair-like experimental model in zebrafish.

CONCLUSIONS

Collectively, this study suggests the ZTI test as a potentially useful protocol to assess stress-/despair-related behaviors, potentially relevant to CNS drug screening and behavioral phenotyping of zebrafish.

Venlafaxine plus melatonin ameliorate reserpine-induced depression-like behavior in zebrafish

Venlafaxine (VEN) is one of the first clinical drugs for the treatment of depression. Long-term use may cause a potentially life-threatening serotonin syndrome. Melatonin (MT) could ameliorate depression behavior. Therefore, the aim of this study was to investigate the antidepressant effects of venlafaxine in combination with melatonin on zebrafish. Reserpine was used to induce depression-like behavioral zebrafish. To explore the effects of combined use of venlafaxine and melatonin on depression-like zebrafish induced by reserpine. We tested the depressive behavior of adult zebrafish through a novel tank test, and evaluated the levels of serotonin (5-HT), dopamine (DA) and noradrenaline (NA) in zebrafish brain using enzyme-linked immunosorbent assay (ELISA), besides that the gene expression of serotonin transporters a (serta), dopamine transporters (dat) and norepinephrine transporters (net), vesicular monoamine transporter2 (vmat2) and monoamine oxidase (mao) were evaluated by qRT-PCR. The results showed that, compared with reserpine-only group, venlafaxine (VEN, 0.025 mg/L) and melatonin (MT, 1 μM) increased the parameters of exploration in the top of the tank and decreased freezing behavior significantly. Compared with reserpine-only group, the use of VEN combined with MT increased serotonin and norepinephrine levels significantly, while there was no obvious difference in dopamine content. The results of qRT-PCR showed that the use of VEN combined with MT significantly reduced the expression of serta and promoted the expression of vmat2, but had no significant effect on the expression of net, dat and mao. The results indicated that venlafaxine combined with melatonin showed more effective role to remedy the depressive symptoms in zebrafish, providing a reference for the clinical application of antidepressants.

The effects of fluorene-9-bisphenol on female zebrafish (Danio rerio) reproductive and exploratory behaviors

Endocrine disruptor chemicals induce adverse effects to animals' development, reproduction and behavior in environment. We investigated the effects of fluorene-9-bisphenol (BHPF), one substitute of bisphenol A, on courtship behavior and exploratory behavior of adult zebrafish. Customized apparatus was used to evaluate courtship behavior. The result showed that the male spent less time with BHPF and anti-oestrogenic fulvestrant (FULV) treated female in region of approaching (ROA). Courtship index between BHPF-exposed female and male decreased. The body orientation of BHPF- and FULV-exposed female to male decreased. Furthermore, BHPF exposure downregulated the expression of genes related to estrogen receptor, steroidogenesis and upregulated oxidative stress related genes. It indicated that BHPF exposure interfered the preference of male and female in courtship, and induced detrimental effects on reproduction. BHPF treatment decreased locomotor activity and time spent in top, increased freezing bouts, and induced anxiety/depression-like behavior. The tyrosine hydroxylase in brain decreased under BHPF exposure. Here we showed the potential adverse effects of BHPF on reproduction and exploratory behaviors.

Zebrafish Mutants Carrying Leptin a (lepa) Gene Deficiency Display Obesity, Anxiety, Less Aggression and Fear, and Circadian Rhythm and Color Preference Dysregulation

Leptin, a hormone secreted by peripheral adipose tissues, regulates the appetite in animals. Recently, evidence has shown that leptin also plays roles in behavioral response in addition to controlling appetite. In this study, we examined the potential function of leptin on non-appetite behaviors in zebrafish model. By using genome editing tool of Transcription activator-like effector nuclease (TALEN), we successfully knocked out leptin a (lepa) gene by deleting 4 bp within coding region to create a premature-translation stop. Morphological and appetite analysis showed the lepa KO fish display a phenotype with obese, good appetite and elevation of Agouti-related peptide (AgRP) and Ghrelin hormones, consistent with the canonical function of leptin in controlling food intake. By multiple behavior endpoint analyses, including novel tank, mirror biting, predator avoidance, social interaction, shoaling, circadian rhythm, and color preference assay, we found the lepa KO fish display an anxiogenic phenotype showing hyperactivity with rapid swimming, less freezing time, less fear to predator, loose shoaling area forming, and circadian rhythm and color preference dysregulations. Using biochemical assays, melatonin, norepinephrine, acetylcholine and serotonin levels in the brain were found to be significantly reduced in lepa KO fish, while the levels of dopamine, glycine and cortisol in the brain were significantly elevated. In addition, the brain ROS level was elevated, and the anti-oxidative enzyme catalase level was reduced. Taken together, by performing loss-of-function multiple behavior endpoint testing and biochemical analysis, we provide strong evidence for a critical role of lepa gene in modulating anxiety, aggression, fear, and circadian rhythm behaviors in zebrafish for the first time.

Evaluation of the Effects of Carbon 60 Nanoparticle Exposure to Adult Zebrafish: A Behavioral and Biochemical Approach to Elucidate the Mechanism of Toxicity

There is a growing concern for the potential toxicity of engineered nanomaterials that have made their way into virtually all novel applications in the electronics, healthcare, cosmetics, technology, and engineering industries, and in particular, biomedical products. However, the potential toxicity of carbon 60 (C₆₀) at the behavioral level has not been properly evaluated. In this study, we used idTracker, a multitracking algorithm to quantitatively assess behavioral toxicity induced by C₆₀ nanoparticles (C₆₀ NPs) in adult zebrafish. We demonstrated that locomotion, novel tank exploration, aggression, shoaling, and color preference activities of the C₆₀ NPs-treated fish was significantly reduced. In addition, the C₆₀ NPs-treated fish also displayed dysregulation of the circadian rhythm by showing lower locomotion activities in both day and night cycles. The biochemical results showed that C₆₀ NPs exposure at low concentration induced oxidative stress and DNA damage, reduced anti-oxidative capacity and ATP (adenosine triphosphate) levels, and induced stress-associated hormones, hypoxia, as well as inflammation marker upregulation in muscle and gill tissues. Together, this work, for the first time, provide direct evidence showing that the chronic exposure of C₆₀ NPs induced multiple behavioral abnormalities in adult zebrafish. Our findings suggest that the ecotoxicity of C₆₀ NPs towards aquatic vertebrates should be carefully evaluated.