Swimming exercise improves cognitive and behavioral disorders in male NMRI mice with sporadic Alzheimer-like disease.

Alzheimer's disease (AD) is associated with cognitive deficits and behavioral disorders such as anxiety and depression. Recent clinical and experimental studies have demonstrated that swimming exercise could be a potential therapy for cognitive and behavioral disorders. The prevalence of anxiety and depression is increasing among patients with AD; hence, further studies are needed to develop therapies for these behavioral abnormalities. The purpose of this study was to evaluate the effects of swimming exercise on memory impairment, anxiety, and depression-like behaviors in a mouse model of sporadic Alzheimer-like disease. Eight days after AD induction by streptozotocin (STZ), mice were subjected to the swimming exercise for four weeks. To assess cognitive functions, anxiety- and depression-related behaviors in animals, Y-maze, novel object recognition, open field, zero maze, sucrose preference, and forced swim tests were used. To understand the possible mechanisms, amyloid-ß (Aß)-42, brain-derived neurotrophic factor (BDNF), glutamate, malondialdehyde (MDA), tumor-necrosis-factor (TNF)-α, and interleukin (IL)-6 levels were measured in the hippocampus. The results of this study indicate that STZ administration impaired cognitive functions, increased anxiety- and depression-related behaviors, and elevated Aß-42, glutamate, MDA, TNF-α, and IL-6 levels in the hippocampus of mice. In contrast, swimming exercise significantly reversed these neurobehavioral disorders, increased BDNF, and decreased both glutamate and TNF-α in the hippocampus of STZ-treated mice. Overall, these findings provide some support for the idea that swimming exercise might be associated with reduced neurobehavioral disorders in patients with Alzheimer's disease. However, further clinical studies on this topic are required to confirm and validate these findings.

Prenatal maternal stress alters depression-related symptoms in a strain - and sex-dependent manner in rodent offspring.

Stress during pregnancy adversely affects foetal development and leads to later behavioural outcomes in offspring. Preclinical studies have reported conflicting effects of prenatal stress on depression-related symptoms in rodent offspring. This study aimed to study the combined effect of strain and sex on prenatal stress outcomes in a single study. To this end, male and female offspring from outbred Wistar and inbred Lewis rats, and outbred NMRI and inbred C57BL6 mice were compared. As outcomes we focussed on depression-related behaviour and related molecular and neurochemical parameters. Prenatally stressed and non-stressed offspring were subjected to the sucrose preference, novelty-suppressed feeding, tail suspension, and forced swim tests. We measured basal and stress-induced corticosterone levels in the serum, and brain-derived-neurotrophic-factor (BDNF), interleukin-1ß, tumor necrosis factor-α, glutamate and serotonin in the brain to determine changes in hypothalamic-pituitary-adrenal-(HPA)-axis function, neuroplasticity, neuroinflammation, and neurotransmission. Our findings revealed that prenatal stress increases depression-like behaviour, HPA-axis (re) activity, pro-inflammatory cytokines and glutamate levels, and decreases BDNF and serotonin levels in a strain and sex-dependent manner in rodent offspring. Overall, male and female Lewis rats, female Wistar rats, male NMRI mice and female C57BL6 mice were found to be most responsive to prenatal stress. Based on these results, we conclude that genetic background and sex contribute to the great diversity in the effects of prenatal maternal stress in rodents.

Glibenclamide mitigates cognitive impairment and hippocampal neuroinflammation in rats with type 2 diabetes and sporadic Alzheimer-like disease.

A growing body of evidence suggests that type 2 diabetes (T2D) is a risk factor for cognitive impairment and dementia. Both preclinical and clinical studies have provided evidence that brain insulin resistance is associated with cognitive decline in patients with T2D and sporadic Alzheimer disease (AD). Accordingly, antidiabetic medications have been suggested as potential drugs for the treatment of cognitive impairments in patients with sporadic AD. This study set out to determine whether glibenclamide (GBC), an antidiabetic agent, can ameliorate cognitive impairments in rats with T2D and sporadic AD. Both animal models were treated with GBC for 23 consecutive days. To assess working and spatial memory, animals were subjected to the Y-maze and Morris water-maze tests. We measured glucose and insulin levels in the blood, and inflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-6 in the hippocampus of animals. Our findings indicated that T2D and sporadic AD impaired memory and elevated TNF-α and IL-6 in the hippocampus. We found increased glucose and insulin levels in the blood of T2D-induced rats but not of sporadic AD rats. In contrast, GBC treatment improved memory impairment, increased insulin, and reduced glucose and hippocampal inflammation in rats with T2D and sporadic AD. This study suggests that GBC could be considered as a potential treatment for cognitive deficits in patients with T2D and sporadic AD. Taken together, this study highlights the need for further studies in humans to test whether GBC treatment is associated with cognitive improvement in sporadic AD patients.

Gut microbiota depletion from early adolescence alters adult immunological and neurobehavioral responses in a mouse model of multiple sclerosis.

Emerging evidence indicates that gut microbiota interacts with immune and nervous systems in the host and plays a critical role in the pathogenesis of multiple sclerosis (MS) and many psychiatric disorders such as depression and anxiety. The aim of this study was to explore the influence of gut bacterial depletion from early adolescence on adult immunological and neurobehavioral responses in mice with experimental-autoimmune-encephalomyelitis (EAE). We used an animal model of gut microbiota depletion induced by antibiotics from weaning to adulthood to assess clinical signs, cognitive function and depression-and anxiety-related symptoms in non-EAE and EAE-induced mice. We measured levels of interferon (IFN)-γ, interleukin (IL)-17A and IL-10 in serum, and BDNF, IL-1ß and tumor necrosis factor (TNF)-α) in the hippocampus. Antibiotic-treated mice displayed a significant delay in the onset of clinical symptoms of EAE. However, a higher severity of EAE was found between days 19-22 post-immunization in antibiotics-treated mice, while a reduction in the clinical signs of MS was observed at days 24-25 post-immunization. Antibiotic administration decreased IFN-γ and IL-17A levels and increased IL-10 in serum of EAE-induced mice. Antibiotic treatment significantly decreased hippocampal BDNF and enhanced learning and memory impairments in EAE-induced mice. However, no significant changes were found in non-EAE mice. Non-EAE and EAE mice treated with antibiotics exhibited increased anxiety-related behaviors, whereas depression-related symptoms and increased hippocampal TNF-α and IL-1ß were only observed in EAE-induced mice treated with antibiotics. This study supports the view that depletion of gut microbiota by antibiotics from weaning profoundly impacts adult immunological and neurobehavioral responses.

Antibiotic Resistance and Biofilm Formation of Enterococcus faecalis in Patient and Environmental Samples.

BACKGROUND: Enterococci are opportunistic pathogens and are a major factor in nosocomial infections. They may contain ebp operon, which upon expression makes them highly prone to biofilm formation on biotic and abiotic surfaces. OBJECTIVES: The aim of the current study was to detect the polymorphism of ebp genes in Enterococcus faecalis. MATERIALS AND METHODS: Samples were isolated from patients (n = 58) and hospital environments (n = 32) of two hospitals in Tehran, Iran. All enterococcal species were identified by species-specific polymerase chain reaction (PCR); the antibiotic resistance pattern against nine antibiotics was determined. The ebp A, ebp B, ebp C and srt C genes were detected by PCR and the biofilm formation by the isolates was evaluated using the microtiter plate method. The genetic diversity of ebp genes was analyzed by restriction fragment length polymorphism (RFLP). RESULTS: The results indicated that, 86% of patient and 29% of environmental isolates carried ebp genes. The ability of the isolates to strongly attach was 62% and 71% for patient and environmental samples, respectively. The RFLP of the ebp showed no genetic variations amongst the isolates. CONCLUSIONS: The results of the antibiotic resistance and other data suggest that there is a possible common clone of E. faecalis, which could rapidly disseminate in patients and the environment.

Adolescent fluoxetine treatment decreases the effects of neonatal immune activation on anxiety-like behavior in mice.

Experimental studies have shown conflicting effects of neonatal infection on anxiety-like behaviors and hypothalamic-pituitary-adrenal (HPA) axis activity in adult rats. We investigated for the first time whether neonatal exposure to lipopolysaccharide (LPS) is associated with increased levels of anxiety-like behaviors in mice. Moreover, there have been several studies showing that adolescent fluoxetine (FLX) treatment can influence HPA axis development and prevent occurrence of psychiatric disorders induced by common early-life insults. In the present study, we also investigated the effects of adolescent FLX exposure following neonatal immune activation on anxiety-like behavior in mice. Neonatal mice were treated to LPS (50µg/kg) or saline on postnatal days (PND) 3 and 5, then male and female mice of both neonatal intervention groups received oral administration of FLX (5 and 10mg/kg/day) or water via regular drinking bottles during the adolescent period (PNDs 35-65). The results showed that postnatal immune challenge increased anxiety-like behavior in the open field, elevated plus-maze and light-dark box in adult mice (PND 90). Furthermore, the adolescent FLX treatment inhibited the anxiety-like behavior induced by neonatal infection in both sexes. However, this study indicates the negative effects of the FLX on normal behavioral symptoms in male control mice. Taken together, the current data provide experimental evidence that neonatal infection increases anxiety levels in male and female mice in adulthood. Additionally, the findings of this study support the hypothesis that an early pharmacological intervention with FLX may be an effective treatment for reducing the behavioral abnormalities induced by common early-life insults.

Maternal infection during late pregnancy increases anxiety- and depression-like behaviors with increasing age in male offspring.

Scientific reports suggest that the exposure to long-term stressors throughout or during late gestation increase anxiety- and depression-like behaviors of offspring in their later life. Moreover, several studies concluded that increasing age correlates with increased anxiety behaviors in humans and rodents. In the present study, we assessed the effects of prenatally administration of equal lipopolysaccharide (LPS) doses in various points of late gestation (days 15, 16, and 17) period, on neuroendocrine and immunological responses of pregnant mice, and subsequent long-lasting consequences of anxiety and depression with increasing age in male offspring at postnatal days (PD) 40 and 80. Four hours after the LPS injection, levels of corticosterone (COR) and pro-inflammatory cytokines (PIC) in pregnant mice, as compared to the control dams, were increased significantly. Furthermore, maternal inflammation raised the levels of COR, anxiety- and depression-like behaviors with increasing age in male offspring in comparison with saline male offspring. These data support other studies demonstrating that maternal stress increases the levels of anxiety and depression in offspring. Additionally, our data confirm other findings indicating that increasing age correlates with increased anxiety or depression behaviors in humans and rodents. Findings of this study suggest that time course of an inflammation response or stressor application during various stages of gestation and ages of offspring are important factors for assessing neuropsychiatric disorders.