Amelioration of Repeated Restraint Stress-Induced Behavioral Deficits and Hippocampal Anomalies with Taurine Treatment in Mice

Emergence of taurine as a therapeutic agent for neurological disorders

Taurine is a sulfur-containing, semi-essential amino acid that occurs naturally in the body. It alternates between inflammation and oxidative stress-mediated injury in various disease models. As part of its limiting functions, taurine also modulates endoplasmic reticulum stress, Ca2+ homeostasis, and neuronal activity at the molecular level. Taurine effectively protects against a number of neurological disorders, including stroke, epilepsy, cerebral ischemia, memory dysfunction, and spinal cord injury. Although various therapies are available, effective management of these disorders remains a global challenge. Approximately 30 million people are affected worldwide. The design of taurine formation could lead to potential drugs/supplements for the health maintenance and treatment of central nervous system disorders. The general neuroprotective effects of taurine and the various possible underlying mechanisms are discussed in this review. This article is a good resource for understanding the general effects of taurine on various diseases. Given the strong evidence for the neuropharmacological efficacy of taurine in various experimental paradigms, it is concluded that this molecule should be considered and further investigated as a potential candidate for neurotherapeutics, with emphasis on mechanism and clinical studies to determine efficacy.

Gallic acid ameliorates behavioral dysfunction, oxidative damage, and neuronal loss in the prefrontal cortex and hippocampus in stressed rats

Gallic acid (GA) is known to be a natural phenolic compound with antioxidant and neuroprotective effects. This study aims to investigate the impact of GA against restraint stress-induced oxidative damage, anxiety-like behavior, neuronal loss, and spatial learning and memory impairment in male Wistar rats. The animals were divided into four groups (n = 8) and subjected to restraint stress for 4 h per day for 14 consecutive days or left undisturbed (control without inducing stress). In the treatment group, the animals were treated with 2 mL normal saline plus 100 mg/kg GA per day for 14 consecutive days (STR + GA group). The animals received the drug or normal saline by gavage 2 h before inducing restraint stress. ELISA assay measured oxidative stress factors. Elevated-plus maze and Morris water maze tests assessed anxiety-like behavior and spatial learning and memory, respectively. Also, neuronal density was determined using Nissl staining. Restraint stress significantly increased MDA and reduced the activities of GPX and SOD in the stressed rats, which were reserved by treatment with 100 mg/kg GA. Restraint stress markedly enhanced the anxiety-like behavior and spatial learning and memory impairment that were reserved by GA. In addition, treatment with GA reduced the neuronal loss in the stressed rats in the hippocampus and prefrontal cortex (PFC) regions. Taken together, our findings suggest that GA has the potential to be used as a good candidate to attenuate neurobehavioral disorders as well as neuronal loss in the hippocampus and PFC induced by restraint stress via reducing oxidative damage.

Tarooneh extract relieves anxiety-like behaviors and cognitive deficits by inhibiting synaptic loss in the hippocampus and frontal cortex in rats subjected to chronic restraint stress

In traditional medicine, Tarooneh (a hardcover of the date palm; Phoenix dactylifera) has known as a sedative and relaxant medicine. In this study, we evaluated the protective effects of Tarooneh in the anxiety-like behavior, cognitive deficit, and neuronal damages in the CA1, CA3, and dentate gyrus (DG) regions of the hippocampus and frontal cortex neurons employing a rat model of chronic restraint stress. The animal received Tarooneh extract for 14 consecutive days in water, and chronic restraint stress was performed daily during this period. The results of the Barnes maze test showed that treatment with Tarooneh significantly improves spatial memory parameters such as latency time to find the target hole, number of errors, and distance traveling compared to the stress group. The EPM results showed that Tarooneh significantly increased the time spent in open arms and the percentage of entries into open arms and significantly decreased the frequency of head dipping behavior compared to animals in the stress group. Golgi-Cox staining indicates that loss of neural spine density in DG, CA1, CA3, and frontal cortex due to chronic restraint stress, was prevented with daily administration of Tarooneh. The results of cresyl-violet staining indicate that Tarooneh significantly increased the number of CV-positive neurons in the frontal cortex and CA1 region of the hippocampus compared to the stress group. Our results suggest that Tarooneh potentially prevented and improved effects in anxiety-like behavior, memory impairment, and synaptic plasticity loss in frontal and hippocampal neurons induced by chronic restraint stress. In conclusion, our results suggest that Tarooneh prevented and improved anxiety-like behavior, cognitive deficit, and neuronal damages in the CA1, CA3, and DG regions of the hippocampus and frontal cortex neurons induced by chronic restraint stress.

Microglia activation in the presence of intact blood-brain barrier and disruption of hippocampal neurogenesis via IL-6 and IL-18 mediate early diffuse neuropsychiatric lupus

INTRODUCTION

Inflammatory mediators are detected in the cerebrospinal fluid of systemic lupus erythematosus patients with central nervous system involvement (NPSLE), yet the underlying cellular and molecular mechanisms leading to neuropsychiatric disease remain elusive.

METHODS

We performed a comprehensive phenotyping of NZB/W-F1 lupus-prone mice including tests for depression, anxiety and cognition. Immunofluorescence, flow cytometry, RNA-sequencing, qPCR, cytokine quantification and blood-brain barrier (BBB) permeability assays were applied in hippocampal tissue obtained in both prenephritic (3-month-old) and nephritic (6-month-old) lupus mice and matched control strains. Healthy adult hippocampal neural stem cells (hiNSCs) were exposed ex vivo to exogenous inflammatory cytokines to assess their effects on proliferation and apoptosis.

RESULTS

At the prenephritic stage, BBB is intact yet mice exhibit hippocampus-related behavioural deficits recapitulating the human diffuse neuropsychiatric disease. This phenotype is accounted by disrupted hippocampal neurogenesis with hiNSCs exhibiting increased proliferation combined with decreased differentiation and increased apoptosis in combination with microglia activation and increased secretion of proinflammatory cytokines and chemokines. Among these cytokines, IL-6 and IL-18 directly induce apoptosis of adult hiNSCs ex vivo. During the nephritic stage, BBB becomes disrupted which facilitates immune components of peripheral blood, particularly B-cells, to penetrate into the hippocampus further augmenting inflammation with locally increased levels of IL-6, IL-12, IL-18 and IL-23. Of note, an interferon gene signature was observed only at nephritic-stage.

CONCLUSION

An intact BBB with microglial activation disrupting the formation of new neurons within the hippocampus represent early events in NPSLE. Disturbances of the BBB and interferon signature are evident later in the course of the disease.

Taurine Alleviates Chronic Social Defeat Stress-Induced Depression by Protecting Cortical Neurons from Dendritic Spine Loss

Abnormal amino acid metabolism in neural cells is involved in the occurrence and development of major depressive disorder. Taurine is an important amino acid required for brain development. Here, microdialysis combined with metabonomic analysis revealed that the level of taurine in the extracellular fluid of the cerebral medial prefrontal cortex (mPFC) was significantly reduced in mice with chronic social defeat stress (CSDS)-induced depression. Therefore, taurine supplementation may be usable an intervention for depression. We found that taurine supplementation effectively rescued immobility time during a tail suspension assay and improved social avoidance behaviors in CSDS mice. Moreover, taurine treatment protected CSDS mice from impairments in dendritic complexity, spine density, and the proportions of different types of spines. The expression of N-methyl D-aspartate receptor subunit 2A, an important synaptic receptor, was largely restored in the mPFC of these mice after taurine supplementation. These results demonstrated that taurine exerted an antidepressive effect by protecting cortical neurons from dendritic spine loss and synaptic protein deficits.

Dietary methionine restriction alleviates oxidative stress and inflammatory responses in lipopolysaccharide-challenged broilers at early age

In this study, we investigated the effect of dietary methionine restriction (MR) on the antioxidant function and inflammatory responses in lipopolysaccharide (LPS)-challenged broilers reared at high stocking density. A total of 504 one-day-old male Arbor Acre broiler chickens were randomly divided into four treatments: 1) CON group, broilers fed a basal diet; 2) LPS group, LPS-challenged broilers fed a basal diet; 3) MR1 group, LPS-challenged broilers fed a methionine-restricted diet (0.3% methionine); and 4) MR2 group, LPS-challenged broilers fed a methionine-restricted diet (0.4% methionine). LPS-challenged broilers were intraperitoneally injected with 1 mg/kg body weight (BW) of LPS at 17, 19, and 21 days of age, whereas the CON group was injected with sterile saline. The results showed that: LPS significantly increased the liver histopathological score (p < 0.05); LPS significantly decreased the serum total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity at 3 h after injection (p < 0.05); the LPS group had a higher content of Interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF)-α, but a lower content of IL-10 than the CON group in serum (p < 0.05). Compared with the LPS group, the MR1 diet increased catalase (CAT), SOD, and T-AOC, and the MR2 diet increased SOD and T-AOC at 3 h after injection in serum (p < 0.05). Only MR2 group displayed a significantly decreased liver histopathological score (p < 0.05) at 3 h, while MR1 and MR2 groups did so at 8 h. Both MR diets significantly decreased serum LPS, CORT, IL-1β, IL-6, and TNF-α contents, but increased IL-10 content (p < 0.05). Moreover, the MR1 group displayed significantly increased expression of nuclear factor erythroid 2-related factor 2 (Nrf2), CAT, and GSH-Px at 3 h; the MR2 group had a higher expression of Kelch-like ECH-associated protein 1 (Keap1), SOD, and GSH-Px at 8 h (p < 0.05). In summary, MR can improve antioxidant capacity, immunological stress, and liver health in LPS-challenged broilers. The MR1 and MR2 groups experienced similar effects on relieving stress; however, MR1 alleviated oxidative stress more rapidly. It is suggested that precise regulation of methionine levels in poultry with stress may improve the immunity of broilers, reduce feed production costs, and increase production efficiency in the poultry industry.

Neurobiological mechanisms of mood disorders: Stress vulnerability and resilience

Stress is an important factor in the development of several human pathologies. The response of rodents and humans to stress depends on many factors; some people and rodents develop stress-related mood disorders, such as depression and anxiety in humans, depression-like and anxiety-like behavior in mice and rats, while others report no new psychological symptoms in response to chronic or acute stress, and are considered susceptible and resilient to stress, respectively. Resilience is defined as the ability to thrive in the face of adversity and is a learned process that can help protect against occupational stressors and mental illnesses. There is growing interest in the underlying mechanisms involved in resilience and vulnerability to depression caused by stress, and some studies have demonstrated that individual variability in the way animals and humans respond to stress depends on several mechanisms, such as oxidative stress, neuronal plasticity, immunology and genetic factors, among others not discussed in this review, this review provides a general overview about this mechanism.

Natural variation in developmental condition has limited effect on spatial cognition in a wild food-caching bird

Laboratory studies show that increased physiological burden during development results in cognitive impairment. In the wild, animals experience a wide range of developmental conditions, and it is critical to understand how variation in such conditions affects cognitive abilities later in life, especially in species that strongly depend on such abilities for survival. We tested whether variation in developmental condition is associated with differences in spatial cognitive abilities in wild food-caching mountain chickadees. Using tail feathers grown during development in juvenile birds, we measured feather corticosterone (Cortf) levels and growth rates and tested these birds during their first winter on two spatial learning tasks. In only 1 of the 3 years, higher feather Cortf was negatively associated with memory acquisition. No significant associations between feather Cortf and any other measurement of spatial cognition were detected in the other 2 years of the study or between feather growth rate and any measurement of cognition during the entire study. Our results suggest that in the wild, naturally existing variation in developmental condition has only a limited effect on spatial cognitive abilities, at least in a food-caching species. This suggests that there may be compensatory mechanisms to buffer specialized cognitive abilities against developmental perturbations.

Serum metabolomic responses to aerobic exercise in rats under chronic unpredictable mild stress

This study analyzed the effects of aerobic exercise on endogenous serum metabolites in response to chronic unpredictable mild stress (CUMS) using a rat model, aiming to identify the metabolic regulatory pathways involved in the antidepressant effect resulted from a 28-day treadmill aerobic exercise intervention. The animals were randomly divided into four groups (n = 8): normal control, normal with aerobic exercise, CUMS control, and CUMS with aerobic exercise. Body weight, sucrose preference and open field tests were performed weekly during the intervention period for changes in depressant symptoms. Serum metabolic profiles obtained by using the LC-MS/MS metabolomics were analyzed to explore the regulatory mechanism for the effect of the aerobic exercise on depression. Behavior tests showed that the aerobic exercise resulted in a significant improvement in depression-like behavior in the CUMS rats. A total of 21 differential metabolites were identified as being associated with depression in serum metabolic profile, of which the aerobic exercise significantly modulated 15, mainly related to amino acid metabolism and energy metabolism. Collectively, this is the first study that LC-MS/MS techniques were used to reveal the modulatory effects of aerobic exercise on the serum metabolic profile of depressed rats and the findings further enriched our understanding of potential mechanisms of aerobic exercise interventions on depression.

Taurine Supplementation as a Neuroprotective Strategy upon Brain Dysfunction in Metabolic Syndrome and Diabetes

Obesity, type 2 diabetes, and their associated comorbidities impact brain metabolism and function and constitute risk factors for cognitive impairment. Alterations to taurine homeostasis can impact a number of biological processes, such as osmolarity control, calcium homeostasis, and inhibitory neurotransmission, and have been reported in both metabolic and neurodegenerative disorders. Models of neurodegenerative disorders show reduced brain taurine concentrations. On the other hand, models of insulin-dependent diabetes, insulin resistance, and diet-induced obesity display taurine accumulation in the hippocampus. Given the possible cytoprotective actions of taurine, such cerebral accumulation of taurine might constitute a compensatory mechanism that attempts to prevent neurodegeneration. The present article provides an overview of brain taurine homeostasis and reviews the mechanisms by which taurine can afford neuroprotection in individuals with obesity and diabetes. We conclude that further research is needed for understanding taurine homeostasis in metabolic disorders with an impact on brain function.

Forkhead Box 1(FoxO1) mediates psychological stress-induced neuroinflammation

OBJECTIVES

 Neuroinflammation plays a key role in cerebrovascular disease (CVD). Neuropsychiatric disorders appear to share an epidemiological association with inflammation, but the mechanisms are unclear. Forkhead box 1 (FoxO1) regulates inflammatory signaling in diabetes and cardiovascular diseases, but its role in psychological stress-induced neuroinflammation remains unknown. Therefore, we investigated the potential involvement of FoxO1 in repeated social defeat stress (RSDS)-induced neuroinflammation.

METHODS

 6-week-old male C57BL/6 J mice were randomly divided into RSDS or control groups. In the RSDS group, mice (18-22 g) were individually subjected to social defeat by an 8-week-old CD-1 mouse (28-32 g) for 10 min daily for 10 consecutive days. At 24 h after this 10-day process, corticosterone (CORT), epinephrine (EPI), hydrogen peroxide, and inflammatory factors (TNF-α, IL-6, IL-1β, and VCAM-1) from serum and brain tissues were assayed using ELISA, real-time PCR, and Western blot. Iba-1 was determined by immunofluorescence (IF), and FoxO1 siRNA was transfected into BV2 cells to further analyze the expression of inflammatory factors.

RESULTS

RSDS significantly increased the levels of TNF-α, IL-6, IL-1β, and VCAM-1 in the serum; it also increased both mRNA and protein expression of these in the brain. FoxO1 was significantly increased after stress, while its knockdown significantly suppressed stress-induced inflammation. Immunofluorescence demonstrated the activation of microglia in the setting of RSDS.

CONCLUSION

RSDS induced a measurable inflammatory response in the blood and brain, and FoxO1 was demonstrated in vitro to aggravate stress-induced inflammation.

Brain-Derived Neurotrophic Factor Potentiates Entorhinal-Dentate but not Hippocampus CA1 Pathway in Adult Male Rats: A Mechanism of Taurine-Modulated BDNF on Learning and Memory

Taurine plays an important role in neural growth and function from early to adult life, particularly in learning and memory via BDNF action. This study tested the hypothesis that BDNF differentially potentiates entorhinal-hippocampal synaptic transmission in vivo in adult rats. In anesthetized male Sprague-Dawley rats, a stainless steel recording electrode with an attached microinjector was placed into CA1 and the dentate gyrus to record fEPSP, and a paired stainless steel electrode was inserted into entorhinal cortex for continuous paired-pulse stimulation of that brain region. In the dentate gyrus, microinjection of BDNF resulted in a gradual increase in the peak slope of the fEPSP. Following the infusion, the peak fEPSP began to rise in about 8 min, reached a maximum of 120 ± 2% (from baseline) by about 20 min, and remained near peak elevation (~115%) for more than 30 min. In contrast, the same dose of BDNF when injected into CA1 had no consistent effect on fEPSP slopes in the CA1. Further, an equimolar cytochrome C (horse heart) infusion had no significant effect on fEPSP slopes in either the dentate gyrus or CA1. The potentiation effect of BDNF in the dentate gyrus is consistent with a significant increase in power spectral density of dentate gyrus field potentials at 70-200 Hz, but not at frequencies below 70 Hz. In addition, the CA1 power spectral density was not affected by BDNF (compared to cytochrome C). These data indicate that in vivo BDNF potentiates entorhinal-hippocampal synaptic transmission in dentate gyrus, but not in CA1.

Lipopolysaccharide exacerbates chronic restraint stress-induced neurobehavioral deficits: Mechanisms by redox imbalance, ASK1-related apoptosis, autophagic dysregulation

Major depressive disorder (MDD) is the foremost leading psychiatric illness prevailing around the globe. It usually exists along with anxiety and other clinical conditions (cardiovascular, cancer, neurodegenerative diseases, and infectious diseases). Chronic restraint stress (RS) and LPS-induce neurobehavioral alterations in rodent models however their interaction studies in association with the pathogenesis of MDD are still unclear. Therefore, the current study was aimed to investigate the LPS influence on chronic RS mediated redox imbalance, apoptosis, and autophagic dysregulation in the hippocampus (HIP) and frontal cortex (FC) of mice brain. Male Balb/c mice were exposed to 28 days consecutive stress (6h/day) with a single-dose LPS challenge (0.83 mg/kg, i.p.) on the last day (Day 28). In addition, we also carried out separate study to understand physiological relevance, where we used the DSS (dextran sulfate sodium), a water soluble polysaccharide (negatively charged) and studied its influence on RS induced neurobehavioral and certain neurochemical anomalies. The obtained results in RS and RS + LPS animal groups showed significant immune dysfunction, depleted monoamines, lowered ATP & NAD level, elevated serum CORT level, serum and brain tissues IL-1β/TNF-α/IL-6, SOD activity but reduced CAT activity. Furthermore, the redox perturbation was found where significantly upregulated P-NFκB p65, Keap-1, Prx-SO3 and downregulated Nrf2, Srx1, Prx2 protein expression was seen in RS + LPS mice. The apoptosis signaling (P-ASK1, P-p38 MAPK, P-SAPK/JNK, cleaved PARP, cleaved Caspase-3, Cyto-C), autophagic impairment (p62, LC3II/I) were noticed in HIP and FC of RS and RS + LPS grouped animals. Our new findings provide a complex interplay of chemical (LPS) and physical (RS) stressors where both single dose LPS challenge and 3% DSS in drinking water (for 7 days) exaggerated chronic RS-induced inflammation, lowered redox status, increased apoptosis and dysregulated autophagy leading drastic neurobehavioral alterations in the mice.

Long-term taurine administration improves motor skills in a tubulinopathy rat model by decreasing oxidative stress and promoting myelination

The taiep rat undergoes hypomyelination and progressive demyelination caused by an abnormal microtubule accumulation in oligodendrocytes, which elicits neuroinflammation and motor behavior dysfunction. Based on taurine antioxidant and proliferative actions, this work explored whether its sustained administration from the embryonic age to adulthood could prevent neuroinflammation, stimulate cell proliferation, promote myelination, and relieve motor impairment. Taurine (50 mg/L of drinking water = 50 ppm) was given to taiep pregnant rats on gestational day 15 and afterward to the male offspring until eight months of age. We measured the levels of nitric oxide (NO), malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA), CXCL1, CXCR2 receptor, growth factors (BNDF and FGF2), cell proliferation, and myelin content over time. Integral motor behavior was also evaluated. Our results showed that taurine administration significantly decreased NO and MDA + 4-HDA levels, increased cell proliferation, and promoted myelination in an age- and brain region-dependent fashion compared with untreated taiep rats. Taurine effect on chemokines and growth factors was also variable. Taurine improved vestibular reflexes and limb muscular strength in perinatal rats and fine movements and immobility episodes in adult rats. These results show that chronic taurine administration partially alleviates the taiep neuropathology.

The intervention of tert-butylhydroquinone protects ethanol-induced gastric ulcer in type II diabetic rats: the role of Nrf2 pathway

Ethanol consumption increases the prevalence of gastric ulcer (GU) in rats with type II diabetes (T2D). Induction of GU by absolute ethanol (5 mL/kg or 3.94 g/kg) in the animal model resembles human ulcer characteristics. The aim was to investigate the role of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the treatment of GU in diabetic condition. The rats were exposed to absolute ethanol 1 h before sacrifice and T2D was induced by combined exposure of high-fat diet and low dose streptozotocin. Pretreatment of tert-butylhydroquinone (tBHQ) (25 and 50 mg/kg), metformin (500 mg/kg), and omeprazole (20 mg/kg) were given once daily for last three consecutive weeks. In ethanol-exposed diabetic rats, pretreatment with tBHQ, omeprazole, and metformin reduced gastric mucosal lesion, ulcer index, histological alterations, malondialdehyde level, and apoptosis. Furthermore, the intervention of tBHQ, omeprazole, and metformin improved the integrity of the stomach mucosa, glutathione, gastric pH, collagen, and goblet cells. tBHQ treatment improved ethanol-induced alterations of Nrf2, catalase, heat shock protein 70 (HSP70), NF-κB, and endothelin-1 expressions in diabetic rats. In diabetic conditions, the incidence of GU is increased due to elevated levels of reactive oxygen species, inflammatory mediators, depleted levels of cellular antioxidants, and altered gastric parameters. The tBHQ intervention could be a rational strategy to protect these changes.

Robustly High Hippocampal BDNF levels under Acute Stress in Mice Lacking the Full-length p75 Neurotrophin Receptor

BACKGROUND

Brain-derived neurotrophic factor (BDNF) exerts its effects on neural plasticity via 2 distinct receptor types, the tyrosine kinase TrkB and the p75 neurotrophin receptor (p75NTR). The latter can promote inflammation and cell death while TrkB is critically involved in plasticity and memory, particularly in the hippocampus. Acute and chronic stress have been associated with suppression of hippocampal BDNF expression and impaired hippocampal plasticity. We hypothesized that p75NTR might be involved in the hippocampal stress response, in particular in stress-induced BDNF suppression, which might be accompanied by increased neuroinflammation.

METHOD

We assessed hippocampal BDNF protein concentrations in wild-type mice compared that in mice lacking the long form of the p75NTR (p75NTR^ExIII-/-) with or without prior exposure to a 1-hour restraint stress challenge. Hippocampal BDNF concentrations were measured using an optimized ELISA. Furthermore, whole-brain mRNA expression of pro-inflammatory interleukin-6 (Il6) was assessed with RT-PCR.

RESULTS

Deletion of full-length p75NTR was associated with higher hippocampal BDNF protein concentration in the stress condition, suggesting persistently high hippocampal BDNF levels in p75NTR-deficient mice, even under stress. Stress elicited increased whole-brain Il6 mRNA expression irrespective of genotype; however, p75NTR^ExIII-/- mice showed elevated baseline Il6 expression and thus a lower relative increase.

CONCLUSIONS

Our results provide evidence for a role of p75NTR signaling in the regulation of hippocampal BDNF levels, particularly under stress. Furthermore, p75NTR signaling modulates baseline but not stress-related Il6 gene expression in mice. Our findings implicate p75NTR signaling as a potential pathomechanism in BDNF-dependent modulation of risk for neuropsychiatric disorders.

Taurine supplementation reduces myeloperoxidase and matrix-metalloproteinase-9 levels and improves the effects of exercise in cognition and physical fitness in older women

Immunosenescence contributes to cognitive impairment and neurodegeneration, and those conditions could be attenuated by non-pharmacological anti-inflammatory strategies, such as exercise and supplementation with the amino acid taurine. Since taurine body content decreases with aging, we investigated the effects of supplementation (alone and combined with exercise) on oxidative stress, extracellular matrix degradation, white blood cells, neurotrophins, cognition and physical fitness of elderly women. Forty-eight women (83.58 ± 6.98 years) were enrolled into exercise training only (EO: n = 13), taurine supplementation (TS: n = 12), exercise training + taurine supplementation (ETTS: n = 11), and control group (CG: n = 12). All interventions lasted 14 weeks. Exercise was applied twice a week, and taurine was given once a day (1.5 g). Data collection occurred before and after interventions with the determination of myeloperoxidase (MPO), matrix metalloproteinase-9 (MMP-9), brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) levels, and white blood cell counts (WBC). Montreal cognitive assessment (MoCA) and physical fitness tests were also evaluated. Concentration of MPO and MMP-9 decreased after intervention in TS (p < 0.05). No effect of time or time × group was observed for WBC parameters; however, univariate analysis showed a significant decrease in lymphocytes for TS, while an increase in monocytes occurred in the CG (p < 0.05). MoCA scores decreased over time in the CG (p < 0.05). Improvements in physical fitness occurred in ETTS (better agility and aerobic capacity), mostly likely due to exercise and boosted by taurine supplementation. No changes in BDNF levels were observed (p > 0.05), while NGF concentration were undetectable in almost subjects. Exercise together with taurine supplementation appears to be a valuable strategy to enhance health-related outcomes in older persons.

Dietary taurine supplementation attenuates lipopolysaccharide-induced inflammatory responses and oxidative stress of broiler chickens at an early age

This study was conducted to investigate the effect of taurine as a prophylactic treatment on antioxidant function and inflammatory responses of broilers challenged with lipopolysaccharide (LPS). A total of 256 one-day-old male Arbor Acres broiler chicks were randomly assigned to four treatments with eight replicates of eight birds (eight birds per cage). Four treatment groups were designated as follows: 1) in the CON group, broilers fed a basal diet; 2) in the LPS group, LPS-challenged broilers fed a basal diet; 3) in the LPS + T1 group, LPS-challenged broilers fed a basal diet supplemented with 5.0 g/kg taurine; and 4) in the LPS + T2 group, LPS-challenged broilers fed a basal diet supplemented with 7.5 g/kg taurine. The LPS-challenged broilers were intraperitoneally injected with 1 mg/kg body weight (BW) of LPS at 16, 18, and 20 d of age, whereas the CON group received an injection of sterile saline. The results showed that broilers injected with LPS exhibited decreased (P < 0.05) the average daily gain (ADG) and the 21-d BW (P < 0.05), while taurine supplementation alleviated the negative effects of LPS. Additionally, the LPS-induced increases (P < 0.05) in serum alanine transaminase and aspartate transaminase activities were reversed by taurine supplementation. The taurines could alleviate the hepatic oxidative stress, with the presence of lower content of malondialdehyde (P < 0.05), higher content of glutathione (P < 0.05), and an increased glutathione peroxidase (GSH-Px) activity (P < 0.05). The concentrations of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in the liver were measured by ELISA kits, and the result showed that dietary taurine supplementation prevented these cytokines increases in the liver of LPS-induced broilers. Taurine reduced the genes expression of IL-1β, TNF-α, IL-6, cyclooxygenase-2, and inducible nitric oxide synthase, whereas it boosted the expression levels of antioxidant-related genes (nuclear factor erythroid 2-related factor 2, heme oxygenase-1, glutamate-cysteine ligase catalytic subunit, and GSH-Px) in the liver of LPS-induced broilers. In conclusion, dietary taurine supplementation in broilers mitigated LPS-induced defects in ADG, oxidative stress, and inflammatory responses.

Early-Life Stress Alters Synaptic Plasticity and mTOR Signaling: Correlation With Anxiety-Like and Cognition-Related Behavior

Early-life stress (ELS) predisposes individuals to psychiatric disorders, including anxiety and depression, and cognitive impairments later in life. However, the underlying molecular mechanisms are not completely understood. Developmental deficits in hippocampal synaptic plasticity are among the primary detrimental alterations in brain function induced by ELS. Impaired synaptic plasticity is usually accompanied by decreased synaptic proteins, such as postsynaptic density 95 (PSD95) and synaptophysin, which are important for synaptic function. The mTOR signaling pathway plays a vital role in regulating protein translation, and mTOR activation is functionally associated with synaptic protein synthesis. In the present study, we observed whether ELS impacts synaptic protein synthesis and mTOR signaling, which is involved in synaptic plasticity. Herein, we established a maternal separation (MS) and chronic restraint stress (CRS) model and evaluated anxiety-like behavior and cognitive function (e.g., learning and memory) in adulthood through behavioral examination and analyzed hippocampal expression levels of PSD95 and synaptophysin. To explore whether the mTOR signaling pathway was associated with ELS, we also examined the activity of mTOR and s6. The behavior tests indicated that maternally separated mice showed increased anxiety-like behavior and cognitive impairments. PSD95 and synaptophysin mRNA and protein expression levels were decreased in the hippocampus, and phosphorylated mTOR and phosphorylated s6 were significantly decreased in maternally separated mice vs. those not exposed to MS. Our data demonstrate that MS impairs synaptic plasticity and inhibits mTOR signaling, specifically via s6. Therefore, we speculate that ELS decreased synaptic plasticity via the inhibition of the mTOR pathway in the hippocampus, which may underlie vulnerability to stress and mental disorders in adulthood.

Alcohol mixed with energy drinks: what about taurine?

RATIONALE

Since energy drinks (EDs) were marketed to the general public as recreational and soft drinks, mixing these with alcohol has become a popular practice, especially in the younger population. Alcohol mixed with EDs (AmEDs) is a particularly alarming combination, given the evidence that consistently associate these drinks with increased risk behaviours and greater alcohol consumption. Caffeine and taurine are commonly found in EDs. In contrast to caffeine, the studies on taurine psychoactive properties and how this amino acid influences ethanol intake alone or in combination with caffeine are not so numerous.

OBJECTIVES

We summarised relevant and available data on the studies focusing on taurine as a psychoactive agent and its influence on ethanol (EtOH)-induced behaviours. Given the increased risk that represents mixing alcohol with energy drinks, we put emphasis on the research exploring the impact of these combinations on motivated behaviour towards EtOH consumption.

RESULTS

The research on taurine properties on motivated behaviour towards EtOH consumption is limited, and mostly all done in combination with caffeine or other molecules. This makes it difficult to elucidate the effect of this amino acid when combined with alcohol.

CONCLUSIONS

Incomplete understanding of the properties and effects of AmEDs is unavoidable until more studies are performed on the influence of taurine on motivation to consume alcohol. Taurine should be further explored, particularly in regard to its potential beneficial applications, motivational properties and synergies with other psychoactive ingredients (i.e. caffeine).

7,8-Dihydroxyflavone alleviated the high-fat diet and alcohol-induced memory impairment: behavioral, biochemical and molecular evidence

RATIONALE

Alcoholism and obesity impart a deleterious impact on human health and affects the quality of life. Chronic consumption of alcohol and western diet has been reported to cause memory deficits. 7,8-dihydroxyflavone (7,8-DHF), a TrkB agonist, comprises antioxidant and anti-inflammatory properties in treating various neurological disorders.

OBJECTIVES

The current study was aimed to determine the protective effect and molecular mechanism of 7,8-DHF against alcohol and high-fat diet (HFD)-induced memory deficits in rats.

METHODS

The adult male Wistar rats were given alcohol (3-15%) and HFD ad libitum for 12 weeks in different experimental groups. 7,8-DHF (5 mg/kg) was intraperitoneally injected daily for the last 4 weeks (9th-12th week).

RESULTS

The alcohol and HFD administration caused cognitive impairment as evaluated through the Morris water maze (MWM) test in alcohol, HFD, and alcohol + HFD-fed animals. The last 4-week treatment of 7,8-DHF (5 mg/kg; i.p.) attenuated alcohol and HFD-induced memory loss. 7,8-DHF treatment also restored the glutathione (GSH) level along with attenuation of nitrite, malondialdehyde content (markers of oxidative and nitrosative stress), and reduction of the acetylcholinesterase activity in the hippocampus of alcohol and HFD-fed animals. Furthermore, the administration of 7,8-DHF caused downregulation of NF-κB, iNOS, and caspase-3 and upregulation of Nrf2, HO-1, and BDNF mRNA level in rat hippocampus.

CONCLUSION

7,8-DHF administration conferred beneficial effects against alcohol and HFD-induced memory deficit via its unique antioxidant, anti-inflammatory, anti-apoptotic potential, along with the activation of TrkB/BDNF signaling pathway in the hippocampus.