Effect of forced treadmill exercise on stimulation of BDNF expression, depression symptoms, tactile memory and working memory in LPS-treated rats

The Individual Division of Food Hoarding in Autumn Brandt's Voles (Lasiopodomys brandtii)

Brandt's voles (Lasiopodomys brandtii), one of the main non-hibernating rodent species in the typical grassland of Inner Mongolia, live in groups and have the behavioral habit of hoarding food in underground warehouses in autumn to prepare for the winter food shortage ahead. The division of labor and cooperation are typical behavior patterns of gregarious mammals, but it is unclear whether Brandt's voles exercise a division of labor in food hoarding before overwintering. To explore the division of food hoarding in Brandt's voles during the autumn period, three treatments, namely added food, added food + competition, and control, were set up with three replicates. An infrared camera was positioned to observe and record the behavior of Brandt's voles under different treatments. Next, behavioral experiments regarding food-hoarding division were performed on individuals. The results showed that (1) Brandt's voles had two types of hoarding behavior, namely high food hoarding and low food hoarding, but not all individuals displayed hoarding behavior. (2) In all treatments, feeding behavior, which was the most important type of behavior, accounted for the highest proportion of all behaviors. (3) There was no significant difference in body weight and sex between high- and low-food-hoarding individuals of Brandt's voles, and there was no significant difference between high- and low-food-hoarding individuals in other divisions of labor either. (4) There was no significant difference in inquiry ability between high- and low-food-hoarding groups, but there was a significant difference in spatial memory. High-food-hoarding individuals had greater spatial memory. In summary, Brandt's voles had two types of hoarding behavior: high food hoarding and low food hoarding. Furthermore, high-food-hoarding individuals had greater spatial memory.

Neuroprotective Effects of Dehydroepiandrosterone and Hericium erinaceus in Scopolamine-induced Alzheimer's Diseases-like Symptoms in Male Rats

BACKGROUND

The neuroprotective effects of Dehydroepiandrosterone (DHEA) and Hericium erinaceus (H. erinaceus) mushroom extract against scopolamine-induced Alzheimer's disease-like symptoms in male Wistar rats were investigated.

METHODS

Sixty-four male Wistar rats were divided into eight groups (n = 8). Scopolamine (SCO) was intraperitoneally injected at a dose of 1 mg/kg/day for 10 days. The treatment groups orally received DHEA (250 mg/kg/day) and/or H. erinaceus (300 mg/kg/day) for 14 days. Afterward, the Morris water maze (MWM) and novel object recognition tests were implemented. Then, animals were anesthetized and the brain tissue samples were separated. Levels of lipid peroxidation (LPO), total antioxidant capacity (TAC), catalase activity (CAT), and brain-derived neurotrophic factor (BDNF) were determined. Also, histopathological studies were evaluated in the brain tissue samples.

RESULTS

Administration of SCO significantly decreased spatial and cognitive memory (p < 0.001). Not only did SCO injection significantly increase the levels of the LPO but also the SCO markedly reduced the levels of the TAC, CAT activity, and the BDNF in the brain tissue. On the other hand, a combination of the DHEA and H. erinaceus showed higher efficacy than the DHEA or H. erinaceus in attenuating behavioral anomalies and improving the antioxidant defense system and BDNF levels. Histological examination was well correlated with biochemical findings regarding SCO neurodegeneration and DHEA and/or H. erinaceus neuroprotection.

CONCLUSION

Interestingly, ADHE and/or H. erinaceus may due to their potential neurotrophic properties be used as a new and beneficial concurrent therapy in the treatment of Alzheimer's disease-like symptoms caused by SCO.

Cannabinoid type 2 receptor inhibition enhances the antidepressant and proneurogenic effects of physical exercise after chronic stress

Chronic stress is a major risk factor for neuropsychiatric conditions such as depression. Adult hippocampal neurogenesis (AHN) has emerged as a promising target to counteract stress-related disorders given the ability of newborn neurons to facilitate endogenous plasticity. Recent data sheds light on the interaction between cannabinoids and neurotrophic factors underlying the regulation of AHN, with important effects on cognitive plasticity and emotional flexibility. Since physical exercise (PE) is known to enhance neurotrophic factor levels, we hypothesised that PE could engage with cannabinoids to influence AHN and that this would result in beneficial effects under stressful conditions. We therefore investigated the actions of modulating cannabinoid type 2 receptors (CB2R), which are devoid of psychotropic effects, in combination with PE in chronically stressed animals. We found that CB2R inhibition, but not CB2R activation, in combination with PE significantly ameliorated stress-evoked emotional changes and cognitive deficits. Importantly, this combined strategy critically shaped stress-induced changes in AHN dynamics, leading to a significant increase in the rates of cell proliferation and differentiation of newborn neurons, overall reduction in neuroinflammation, and increased hippocampal levels of BDNF. Together, these results show that CB2Rs are crucial regulators of the beneficial effects of PE in countering the effects of chronic stress. Our work emphasises the importance of understanding the mechanisms behind the actions of cannabinoids and PE and provides a framework for future therapeutic strategies to treat stress-related disorders that capitalise on lifestyle interventions complemented with endocannabinoid pharmacomodulation.

Hibiscetin attenuates lipopolysaccharide-evoked memory impairment by inhibiting BDNF/caspase-3/NF-κB pathway in rodents

This study explores the neuroprotective potential of hibiscetin concerning memory deficits induced by lipopolysaccharide (LPS) injection in rats. The aim of this study is to evaluate the effect of hibiscetin against LPS-injected memory deficits in rats. The behavioral paradigms were conducted to access LPS-induced memory deficits. Various biochemical parameters such as acetyl-cholinesterase activity, choline-acetyltransferase, antioxidant (superoxide dismutase, glutathione transferase, catalase), oxidative stress (malonaldehyde), and nitric oxide levels were examined. Furthermore, neuroinflammatory parameters such as tumor necrosis factor-α, interleukin-1β (IL-1β), IL-6, and nuclear factor-kappa B expression and brain-derived neurotrophic factor as well as apoptosis marker i.e., caspase-3 were evaluated. The results demonstrated that the hibiscetin-treated group exhibited significant recovery in LPS-induced memory deficits in rats by using behavioral paradigms, biochemical parameters, antioxidant levels, oxidative stress, neuroinflammatory markers, and apoptosis markers. Recent research suggested that hibiscetin may serve as a promising neuroprotective agent in experimental animals and could offer an alternative in LPS-injected memory deficits in rodent models.

Running from depression: the antidepressant-like potential of prenatal and pre-pubertal exercise in adolescent FSL rats exposed to an early-life stressor

OBJECTIVE

We aimed to answer the questions of whether early-life (perinatal and/or juvenile) exercise can induce antidepressant-like effects in a validated rodent model of depression, and whether such early-life intervention could prevent or reverse the adverse effects of early-life stress in their offspring.

METHODS

Male and female Flinders sensitive line rats born to a dam that exercised during gestation, or not, were either maternally separated between PND02 and 16 and weaned on PND17 or not. Half of these animals then underwent a fourteen-day low-intensity exercise regimen from PND22. Baseline depressive-like behaviour was assessed on PND21 and then reassessed on PND36, whereafter hippocampal monoamine levels, redox state markers and metabolic markers relevant to mitochondrial function were measured.

RESULTS

Pre-pubertal exercise was identified as the largest contributing factor to the observed effects, where it decreased immobility time in the FST by 6%, increased time spent in the open arms of the EPM by 9%. Hippocampal serotonin and norepinephrine levels were also increased by 35% and 26%, respectively, whilst nicotinic acid was significantly decreased.

CONCLUSION

These findings suggest that pre-pubertal low-intensity exercise induces beneficial biological alterations that could translate into antidepressant behaviour in genetically susceptible individuals.

The effects of treadmill exercise on brain angiogenesis in ovariectomized rats

Menopause is associated with vascular dysfunction attributed to reduced estrogen levels. Exercise has been proposed to promote angiogenesis and vascular dysfunction. However, studies of brain angiogenesis during menopause are limited. We analyzed the effects of exercise on angiogenesis-related factors in menopausal rat model. Twenty-week-old female Sprague-Dawley rats (N = 18) were randomly divided into a normal control group (N, n = 6), an ovariectomized control group (OVX, n = 6), and an ovariectomy + exercise group (OVX-EX, n = 6). Treadmill exercises were conducted in the OVX-EX group for 8 weeks (15-60 m/min, 1 h/day, and 5 days/week). The current study showed that the expression of angiogenesis-related factors (platelet-derived growth factor subunit A, B, vascular endothelial growth factor, angiopoietin 1, and angiopoietin 2) significantly decreased in the cortex of the OVX group. However, these factors were significantly restored in the cortex of the OVX-EX group after 8 weeks of treadmill exercise. In summary, estrogen deficiency causes vascular dysfunction by inhibiting the expression of angiogenesis-related factors. However, exercise can restore angiogenesis-related factors in OVX rats. Exercise eventually prevents vascular dysfunction in the brain and may help prevent cognitive dysfunction in menopausal women.

Neurological, Behavioral, and Pathophysiological Characterization of the Co-Occurrence of Substance Use and HIV: A Narrative Review

Combined antiretroviral therapy (cART) has greatly reduced the severity of HIV-associated neurocognitive disorders in people living with HIV (PLWH); however, PLWH are more likely than the general population to use drugs and suffer from substance use disorders (SUDs) and to exhibit risky behaviors that promote HIV transmission and other infections. Dopamine-boosting psychostimulants such as cocaine and methamphetamine are some of the most widely used substances among PLWH. Chronic use of these substances disrupts brain function, structure, and cognition. PLWH with SUD have poor health outcomes driven by complex interactions between biological, neurocognitive, and social factors. Here we review the effects of comorbid HIV and psychostimulant use disorders by discussing the distinct and common effects of HIV and chronic cocaine and methamphetamine use on behavioral and neurological impairments using evidence from rodent models of HIV-associated neurocognitive impairments (Tat or gp120 protein expression) and clinical studies. We also provide a biopsychosocial perspective by discussing behavioral impairment in differentially impacted social groups and proposing interventions at both patient and population levels.

High-intensity interval training improves long-term memory and increases hippocampal antioxidant activity and BDNF levels in ovariectomized Wistar rats

Menopause is the period in which women cease to produce the hormone estrogen, which can trigger physiological, cognitive, and behavioral changes. In this context, alternatives are needed that can reduce the effects provided by menopause, specifically in terms of cognitive and behavioral aspects. High-intensity interval training (HIIT) is an exercise protocol that has shown the potential to improve cognition by promoting an increase in antioxidant defenses and BDNF levels. Therefore, the aim of this study was to evaluate the effects of HIIT on behavior and hippocampal neurochemistry in ovariectomized adult rats. Four groups of rats were divided into: females without ovariectomy surgery and sedentary (SHAM-SED); females with ovariectomy surgery and sedentary (OVX-SED); females without ovariectomy surgery and trained (SHAM-HIIT); females with ovariectomy surgery and trained (OVX-HIIT). After the surgical procedure and the HIIT protocol, the animals underwent anxiety (elevated plus maze and open field) and memory (novel object recognition) tests. Corticosterone was measured in blood and BDNF levels and redox status were evaluated in the hippocampus. The OVX-SED group showed low BDNF levels and antioxidant enzymes, which may be linked to the observed memory impairments. The HIIT protocol (SHAM-HIIT and OVX-HIIT groups) increased the BDNF levels and antioxidant enzymes in the hippocampus, improving the animals' memory. However, HIIT also led to increased plasma corticosterone and anxiety-like behaviors. The ovariectomy procedure induced memory impairment probably due to reductions in hippocampal BDNF levels and redox imbalance. The HIIT protocol demonstrates promising results as an alternative to improve memory in ovariectomized rats.

Ginsenoside-Rg1 synergized with voluntary running exercise protects against glial activation and dysregulation of neuronal plasticity in depression

Depression is a common psychological disease accompanied by mental disorders and somatic symptoms. However, the underlying mechanisms regarding the pathogenesis of depression are still not clear. Neuronal damage resulting from inflammation is considered to be one of the important risk factors for depression. Ginsenoside-Rg1, a sterol extract extracted from ginseng herbs, has been shown to have neuroprotective effects against neurodegenerative diseases. Moreover, running exercise, a simple behavioral therapy, has been recently shown to have antidepressant effects. However, whether these two synergized strategies are more efficient in depression treatment, especially the neural mechanisms underlying this practical and interesting treatment is unknown. In this study, we have shown that ginsenoside-Rg1 synergized with voluntary running exercise exerts more efficiency on suppressing neuroinflammation, up-regulating expression of neurotrophic factors, and synaptic-related proteins, ameliorating neuronal structural damages than that of ginsenoside-Rg1 or voluntary exercise alone, suggesting its better neuroprotective effects. More importantly, the antidepressant-like effect of this synergistic treatment was also significantly better than either of these two treatments. These results suggest that ginsenoside-Rg1, synergized with voluntary running, may have higher efficacy in the treatment of depression through anti-inflammation and the improvement of neuroplasticity. These findings may provide a new perspective for the development of a therapeutic strategy for depression.

Study on the Mechanism for SIRT1 during the Process of Exercise Improving Depression

The mechanism behind the onset of depression has been the focus of current research in the neuroscience field. Silent information regulator 1 (SIRT1) is a key player in regulating energy metabolism, and it can regulate depression by mediating the inflammatory response (e.g., nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β)), gene expression in the nucleus accumben (NAc) and CA1 region of the hippocampus (e.g., nescient helix-loop-helix2 (NHLH2), monoamine oxidase (MAO-A), and 5-Hydroxyindole-3-acetic acid (5-HIAA)), and neuronal regeneration in the CA3 region of the hippocampus. Exercise is an important means to improve energy metabolism and depression, but it remains to be established how SIRT1 acts during exercise and improves depression. By induction and analysis, SIRT1 can be activated by exercise and then improve the function of the hypothalamic-pituitary-adrenal (HPA) axis by upregulating brain-derived neurotrophic factors (BDNF), inhibit the inflammatory response (suppression of the NF-κB and TNF-α/indoleamine 2,3-dioxygenase (IDO)/5-Hydroxytryptamine (5-HT) pathways), and promote neurogenesis (activation of the insulin-like growth factor1 (IGF-1) and growth-associated protein-43 (GAP-43) pathways, etc.), thereby improving depression. The present review gives a summary and an outlook based on this finding and makes an analysis, which will provide a new rationale and insight for the mechanism by which exercise improves depression.

Memory impairments in rodent depression models: A link with depression theories

More than 80% of depressed patients struggle with learning new tasks, remembering positive events, or concentrating on a single topic. These neurocognitive deficits accompanying depression may be linked to functional and structural changes in the prefrontal cortex and hippocampus. However, their mechanisms are not yet completely understood. We conducted a narrative review of articles regarding animal studies to assess the state of knowledge. First, we argue the contribution of changes in neurotransmitters and hormone levels in the pathomechanism of cognitive dysfunction in animal depression models. Then, we used numerous neuroinflammation studies to explore its possible implication in cognitive decline. Encouragingly, we also observed a positive correlation between increased oxidative stress and a depressive-like state with concomitant memory deficits. Finally, we discuss the undeniable role of neurotrophin deficits in developing cognitive decline in animal models of depression. This review reveals the complexity of depression-related memory impairments and highlights the potential clinical importance of gathered findings for developing more reliable animal models and designing novel antidepressants with procognitive properties.

Fatty Acid-Derived N-acylethanolamines Dietary Supplementation Attenuates Neuroinflammation and Cognitive Impairment in LPS Murine Model

Neuroinflammation plays a critical role in the pathogenesis of most neurological and neurodegenerative diseases and therefore represents a potential therapeutic target. In this regard, accelerating the resolution process in chronic neuroinflammation may be an effective strategy to deal with the cognitive consequences of neuropathology and generalized inflammatory processes. N-acylethanolamine (NAE) derivatives of fatty acids, being highly active lipid mediators, possess pro-resolving activity in inflammatory processes and are promising agents for the suppression of neuroinflammation and its consequences. This paper is devoted to a study of the effects played by dietary supplement (DS), containing a composition of fatty acid-derived NAEs, obtained from squid Berryteuthis magister, on the hippocampal neuroinflammatory and memory processes. By detecting the production of pro-inflammatory cytokines and glial markers, a pronounced anti-inflammatory activity of DS was demonstrated both in vitro and in vivo. DS administration reversed the LPS-induced reduction in hippocampal neurogenesis and memory deterioration. LC-MS analysis revealed an increase in the production of a range of NAEs with well-documented anti-inflammatory activity in response to the administered lipid composition. To conclude, we found that tested DS suppresses the neuroinflammatory response by reducing glial activation, positively regulates neural progenitor proliferation, and attenuates hippocampal-dependent memory impairment.

Exercise hormone irisin prevents physical inactivity-induced cognitive decline in mice

We previously reported that physical inactivity (PI) induces cognitive decline and depressive states, which were ameliorated by regular exercise. However, the mechanism underlying the preventive effect of exercise remains unelucidated. Irisin has recently been identified as an exercise-inducible myokine that improves cognitive impairment. Plasma irisin levels increase during physical exercise; therefore, PI could lead to a decline in cognitive function by reducing plasma irisin. Therefore, this study aimed to examine whether irisin is associated with cognitive decline and mental deterioration altered by PI and exercise. The mice were housed for eight weeks in the PI cage, whose living space was one-sixth that of a standard cage. Simultaneously, the mice were subjected to regular exercise in the presence or absence of an irisin-neutralizing antibody. PI increased the epididymal fat mass without increasing body weight, muscle mass, or plasma corticosterone levels. Additionally, PI induced anxiety, depressive states, and a decline in working memory. In contrast, regular exercise after PI elevated irisin levels in plasma and increased fibronectin type III domain-containing 5 (FNDC5) and peroxisome proliferator-activated receptor gammacoactivator 1α expression in skeletal muscle. Regular exercise also increased hippocampal brain-derived neurotrophic factor (BDNF) expression and BrdU-positive cells, alleviating cognitive decline and mental deterioration induced by PI. The beneficial effects of exercise were compromised by the administration of an irisin-neutralizing antibody. Moreover, plasma irisin level was positively correlated with working memory, hippocampal BDNF levels, and hippocampal cell proliferation. These findings suggest that exercise-inducible irisin is critical for maintaining cognitive function in the PI state.

Impact of two different types of exercise training on AMPH addiction: Role of hippocampal neurotrophins

INTRODUCTION

Amphetamine (AMPH) abuse results in neurobehavioral alterations related to the reward circuit. The hippocampus plays a role in cognition, reward, and drug addiction. There are no pharmacological approaches to prevent AMPH relapse. Physical exercise has been studied as a non-pharmacological promising influence to attenuate reward symptoms related to addictive drugs.

OBJECTIVE

This study aimed to compare the effects of non-weight-loaded and weight-loaded physical exercise on behavioral (relapse, memory and anxiety) and hippocampal molecular parameters associated with AMPH addiction in Wistar rats.

METHODS

Male rats were subjected to the AMPH-Conditioned Place Preference (CPP) paradigm. After 8-conditioning days, they were subjected to swimming physical exercise protocol (without or with weight-load). Behavioral evaluations were performed to assess the influence of both exercise protocols in addiction parameters, including relapse after AMPH reconditioning, working memory, locomotor activity, and anxiety-like symptoms. Subsequently, protein levels of Brain-Derived Neurotrophic Factor (BDNF) and pro-BDNF ex-vivo assays were carried out in samples of the hippocampus of the animals.

RESULTS

AMPH relapse and anxiety-like behaviors were reduced only in rats subjected to non-weight-loaded exercise. Hippocampal BDNF and pro-BDNF immunoreactivity were increased in non-weight-loaded exercise rats. Behavioral and molecular analyses were not modified in rats subjected to weight-loaded exercise.

CONCLUSION

These findings demonstrate that non-weight-loaded exercise was more effective against relapse and anxiety-like behavior induced by AMPH. Non-weight-loaded exercise upregulated the hippocampal immunocontent levels in rats.