Long-term exercise from adolescence to adulthood reduces anxiety- and depression-like behaviors following maternal immune activation in offspring

Physical activity and social anxiety symptoms among Chinese college students: a serial mediation model of psychological resilience and sleep problems

BACKGROUND

Social anxiety symptoms are common and harmful psychological illness in college students. Although some studies have illustrated that physical activity could reduce social anxiety symptoms, the specific mechanism is still unclear. Based on theoretical studies on resilience and sleep, this study constructed a serial mediation model to explore whether they mediate between physical activity and social anxiety symptoms among college students.

METHODS

This study surveyed 9,530 college students from three colleges in China to explore the mediating effect of physical activity and sleep problems between physical activity and social anxiety symptoms. Participants were investigated with the International Physical Activity Questionnaire, Connor-Davidson Resilience Scale, Sleep-related problems, and the Social Interaction Anxiety Scale and the Social Phobia Scale. Correlations between variables were analysed using Pearson correlation analysis and mediation analyses were performed using SPSS PROCESS macro 3.3 software.

RESULT

The study found that physical activity was negatively associated with social anxiety symptoms and sleep problems, but positively with psychological resilience. After controlling for sociodemographic variables, physical activity can not only indirectly alleviate social anxiety symptoms through the separate mediation of psychological resilience and sleep problems, but also through the serial mediation of psychological resilience and sleep problems.

CONCLUSION

These results suggest that improving physical activity levels could reduce social anxiety scores by increasing psychological resilience and sleep quality. This is of great reference significance for the prevention and intervention of college students' mental health.

Adolescent activity-based anorexia has a substantial and prolonged impact on social behavior in young adult female rats

Activity-based anorexia (ABA) is a rodent model of anorexia nervosa (AN) that induces several key components of AN, including voluntary reduction in food intake, reduced body weight, hyperactivity, and alterations to the hypothalamic-pituitary-adrenal (HPA) axis. Previous research has demonstrated persistently increased anxiety-like behavior in the elevated plus maze (EPM), a test measuring avoidance of novel and open areas in adult female rats that experienced ABA during adolescence and are weight-restored in adulthood. Whether the same behavioral effects of two bouts of adolescent ABA emerge in response to different anxiety-provoking stimuli, however, has not been explored. We used the social partition (SP), novelty suppressed feeding (NSF), marble burying, and EPM tests to explore whether two bouts of adolescent ABA have persistent effects on anxiety-like behavior in weight restored young adult female rats. One-way ANOVA analyses revealed that female rats that experienced two bouts of ABA during adolescence had increased anxiety-like behavior in the EPM and SP tests in young adulthood following weight restoration compared with controls. These data demonstrate that the enduring behavioral effects of two bouts of adolescent ABA are specific to particular anxiety-provoking stimuli and suggest that adolescent ABA has enduring effects on social relationships.

Immune and metabolic challenges induce changes in pain sensation and related pathways in the hypothalamus

The hypothalamic molecular processes participate in the regulation of the neuro-immune-endocrine system, including hormone, metabolite, chemokine circulation, and corresponding physiological and behavioral responses. RNA-sequencing profiles were analyzed to understand the effect of juvenile immune and metabolic distress 100 days after virally elicited maternal immune activation during gestation in pigs. Over 1,300 genes exhibited significant additive or interacting effects of gestational immune activation, juvenile distress, and sex. One-third of these genes presented multiple effects, emphasizing the complex interplay of these factors. Key functional categories enriched among affected genes included sensory perception of pain, steroidogenesis, prolactin, neuropeptide, and inflammatory signaling. These categories underscore the intricate relationship between gestational immune activation during gestation, distress, and the response of hypothalamic pathways to insults. These effects were sex-dependent for many genes, such as Prdm12, Oprd1, Isg20, Prl, Oxt, and Vip. The prevalence of differentially expressed genes annotated to proinflammatory and cell cycle processes suggests potential implications for synaptic plasticity and neuronal survival. The gene profiles affected by immune activation, distress, and sex pointed to the action of transcription factors SHOX2, STAT1, and REST. These findings underscore the importance of considering sex and postnatal challenges when studying causes of neurodevelopmental disorders and highlight the complexity of the "two-hit" hypothesis in understanding their etiology. Our study furthers the understanding of the intricate molecular responses in the hypothalamus to gestational immune activation and subsequent distress, shedding light on the sex-specific effects and the potential long-lasting consequences on pain perception, neuroendocrine regulation, and inflammatory processes.NEW & NOTEWORTHY The interaction of infection during gestation and insults later in life influences the molecular mechanisms in the hypothalamus that participate in pain sensation. The response of the hypothalamic transcriptome varies between sexes and can also affect synapses and immune signals. The findings from this study assist in the identification of agonists or antagonists that can guide pretranslational studies to ameliorate the effects of gestational insults interacting with postnatal challenges on physiological or behavioral disorders.

Voluntary wheel running from early adolescence reduces disease progression, and anxiety- and depression-related symptoms in an adult male mouse model of rheumatoid arthritis

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease that progressively destroys synovial joints and leads to chronic systemic inflammation. This autoimmune disorder is associated with increased anxiety- and depression-related symptoms, which reduces quality of life. Clinical and experimental evidence suggests that higher physical activity from early adolescence may prevent chronic diseases and reduce the risk of mental health problems in adulthood. This study aimed to assess whether voluntary wheel running from early adolescence can decrease clinical symptoms, anxiety- and depression-related behaviors in adult mice with rheumatoid arthritis. Adolescent male mice were exposed to voluntary wheel running until adulthood and got collagen-induced arthritis. We measured body weight, the thickness of the hind paw and knee joint (clinical signs), anxiety- and depression-related behaviors, serum testosterone, and cytokines (IFN-γ IL-1β, IL-6, TNF-α, IL-10). The findings showed that collagen-induced arthritis resulted in anxious-like behavior, increased anhedonia, elevated IL-6, IL-1β, TNF-α, and IFN-γ, and decreased testosterone levels in the serum of mice. However, no change was observed in behavioral despair. We found that higher physical activity from early adolescence significantly reduced the severity of clinical signs, anxiety- and anhedonia-like behaviors, and decreased behavioral despair in RA-induced mice. In addition, the running wheel exposure normalized RA-induced abnormalities in testosterone and inflammatory cytokines in mice. Altogether, this study suggests that higher physical activity from early adolescence may make mice less vulnerable or resistant to RA-induced clinical symptoms and anxiety- and depression-related behaviors by changing testosterone and inflammatory cytokines productions in adulthood.

Restoring prefrontal cortical excitation-inhibition balance with cannabidiol ameliorates neurobehavioral abnormalities in a mouse model of neurodevelopmental disorders

Maternal immune activation (MIA) resulting from viral infections during pregnancy is linked to increased rates of neurodevelopmental disorders in offspring. However, the mechanisms underlying MIA-induced neurobehavioral abnormalities remain unclear. Here, we used a poly (I:C)-induced MIA mouse model to demonstrate the presence of multiple behavioral deficits in male offspring. Through RNA sequencing (RNA-seq), we identified significant upregulation of genes involved in axonogenesis, synaptogenesis, and glutamatergic synaptic neurotransmission in the mPFC of MIA mice. Electrophysiological analyses further revealed an excitatory-inhibitory (E/I) synaptic imbalance in mPFC pyramidal neurons, leading to hyperactivity in this brain region. Cannabidiol (CBD) effectively alleviated the behavioral abnormalities observed in MIA offspring by reducing glutamatergic transmission and enhancing GABAergic neurotransmission of mPFC pyramidal neurons. Activation of GPR55 by lipid lysophosphatidylinositol (LPI), an endogenous GPR55 agonist, specifically in the mPFC of healthy animals led to MIA-associated behavioral phenotypes, which CBD could effectively reverse. Moreover, we found that a GPR55 antagonist can mimic CBD's beneficial effects, indicating that CBD's therapeutic effects are mediated via the LPI-GPR55 signaling pathway. Therefore, we identified mPFC as a primary node of a neural network that mediates MIA-induced behavioral abnormalities in offspring. Our work provides insights into the mechanisms underlying the developmental consequences of MIA and identifies CBD as a promising therapeutic approach to alleviate these effects.

Prenatal and postnatal challenges affect the hypothalamic molecular pathways that regulate hormonal levels

This study aimed to improve our understanding of how the hypothalamus mediates the effects of prenatal and postnatal challenges on behavior and sensitivity to stimuli. A pig model of virally initiated maternal immune activation (MIA) was used to investigate potential interactions of the prenatal challenge both with sex and with postnatal nursing withdrawal. The hypothalami of 72 females and males were profiled for the effects of MIA and nursing withdrawal using RNA-sequencing. Significant differential expression (FDR-adjusted p value < 0.05) was detected in the profile of 222 genes. Genes involved in the Gene Ontology biological process of regulation of hormone levels tended to be over-expressed in individuals exposed to both challenges relative to individuals exposed to either one challenge, and most of these genes were over-expressed in MIA females relative to males across nursing levels. Differentially expressed genes included Fshb, Ttr, Agrp, Gata3, Foxa2, Tfap2b, Gh1, En2, Cga, Msx1, and Npy. The study also found that prenatal and postnatal challenges, as well as sex, impacted the regulation of neurotransmitter activity and immune effector processes in the hypothalamus. In particular, the olfactory transduction pathway genes were over-expressed in weaned MIA males, and several transcription factors were potentially found to target the differentially expressed genes. Overall, these results highlight how multiple environmental challenges can interact and affect the molecular mechanisms of the hypothalamus, including hormonal, immune response, and neurotransmitter processes.

Maternal adherence to healthy lifestyle and risk of depressive symptoms in the offspring: mediation by offspring lifestyle

BACKGROUND

Adherence to healthy lifestyles can be beneficial for depression among adults, but the intergenerational impact of maternal healthy lifestyles on offspring depressive symptoms is unknown.

METHODS

In total, 10 368 mothers in Nurses' Health Study II and 13 478 offspring in the Growing Up Today Study were paired. Maternal and offspring healthy lifestyles were defined as a composite score including a healthy diet, normal body mass index (BMI), never-smoking, light-to-moderate consumption of alcohol, and regular moderate-to-vigorous physical activity. Maternal lifestyles were assessed during their offspring's childhood. Offspring depressive symptoms were repeatedly assessed five times using the Center for Epidemiological Studies Depression Scale-10 (CESD-10); the offspring were between the ages of 14 and 30 when the first CESD-10 was assessed. Covariates included maternal variables (age at baseline, race/ethnicity, antidepressant use, pregnancy complications, etc.) and offspring age and sex.

RESULTS

Children of mothers with the healthiest lifestyle had significantly fewer depressive symptoms (a 0.30 lower CESD-10 score, 95% confidence interval (CI) 0.09-0.50) in comparison with children of mothers with the least healthy lifestyle. The association was only found significant in female offspring but not in males. For individual maternal lifestyle factors, a normal BMI, never-smoking, and adherence to regular physical activity were independently associated with fewer depressive symptoms among the offspring. The association between maternal healthy lifestyles and offspring depressive symptoms was mediated by offspring's healthy lifestyles (mediation effect: 53.2%, 95% CI 15.8-87.3).

CONCLUSIONS

Our finding indicates the potential mechanism of intergenerational transmission of healthy lifestyles to reduce the risk of depressive symptoms in offspring.

Physical activity in a swimming pool attenuates memory impairment by reducing glutamate and inflammatory cytokines and increasing BDNF in the brain of mice with type 2 diabetes

Type 2 diabetes is a risk factor for the development of cognitive impairment. Increasing evidence suggests that regular exercise is beneficial for the treatment of clinical symptoms in diabetic patients. The current study aimed to evaluate whether increasing physical activity through swimming training can reduce memory impairment in an animal model of type 2 diabetes. Diabetes and non-diabetes mice underwent swimming training for four weeks, and then working, spatial, and recognition memory were evaluated using three behavioral tests. Body weight, glucose, and insulin resistance were monitored. We also measured inflammatory cytokines (interleukin (IL)- 6, IL-1β, and tumor-necrosis-factor (TNF)-α), an anti-inflammatory cytokine (IL-10), and brain-derived-neurotrophic-factor (BDNF), and glutamate levels in the hippocampus or prefrontal cortex of mice. The findings showed that diabetes increased body weight, glucose, and insulin resistance, impaired working, spatial and recognition memory, increased levels of IL-6, IL-1β, TNF-α, and glutamate levels, and decreased BDNF in the hippocampus of diabetic mice. While higher physical activity was associated with reduced body weight, glucose, and insulin resistance, attenuated memory impairment, IL-6, IL-1β, TNF-α, and glutamate, and increased BDNF levels in the hippocampus and prefrontal cortex of diabetic mice. This study shows that swimming training can normalize body weight and glucose-insulin axis and reduce inflammation and glutamate in the hippocampus and enhance the neurotrophic system in both the hippocampus and prefrontal cortex of diabetic mice. This study also suggests that higher physical activity through swimming training can improve cognitive impairment in a mouse model of type 2 diabetes.

Subsequent maternal sleep deprivation aggravates neurobehavioral abnormalities, inflammation, and synaptic function in adult male mice exposed to prenatal inflammation

OBJECTIVE

Studies have suggested that prenatal exposure to inflammation increases the risk of neuropsychiatric disorders, including anxiety, depression, and cognitive dysfunction. Because of anatomical and hormonal alterations, pregnant women frequently experience sleep dysfunction, which can enhance the inflammatory response. The aim of this study was to explore the effects of maternal sleep deprivation on prenatal inflammation exposure-induced behavioral phenotypes in offspring and identify the associated mechanisms.

METHODS

Pregnant mice received an intraperitoneal injection of lipopolysaccharide (LPS) on gestational day 15 and were subsequently subjected to sleep deprivation during gestational days 15-21. Anxiety-like behavior was evaluated by the open field test and the elevated plus maze test. Depression-like behavior was assessed by the tail suspension test and the forced swimming test. Cognitive function was determined using the Morris water maze test. The levels of markers of inflammation and synaptic function were examined employing general molecular biological techniques.

RESULTS

The results showed that prenatal exposure to LPS resulted in anxiety- and depression-like symptoms and learning and memory deficits, and these effects were exacerbated by maternal sleep deprivation. Furthermore, maternal sleep deprivation aggravated the prenatal LPS exposure-induced increase in the expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α and decrease in the levels of postsynaptic density-95 and synaptophysin in the hippocampus.

DISCUSSION

Collectively, these results suggested that maternal sleep deprivation exacerbates anxiety, depression, and cognitive impairment induced by prenatal LPS exposure, effects that were associated with an inflammatory response and synaptic dysfunction.

Adolescent swimming exercise following maternal valproic acid treatment improves cognition and reduces stress-related symptoms in offspring mice: Role of sex and brain cytokines

Valproic acid (VPA) treatment during pregnancy is a risk factor for developing autism spectrum disorder, cognitive deficits, and stress-related disorders in children. No effective therapeutic strategies are currently approved to treat or manage core symptoms of autism. Active lifestyles and physical activity are closely associated with health and quality of life during childhood and adulthood. This study aimed to evaluate whether swimming exercise during adolescence can prevent the development of cognitive dysfunction and stress-related disorders in prenatally VPA-exposed mice offspring. Pregnant mice received VPA, afterwards, offspring were subjected to swimming exercise. We assessed neurobehavioral performances and inflammatory cytokines (interleukin-(IL)6, tumor-necrosis-factor-(TNF)α, interferon-(IFN)γ, and IL-17A) in the hippocampus and prefrontal cortex of offspring. Prenatal VPA treatment increased anxiety-and anhedonia-like behavior and decreased social behavior in male and female offspring. Prenatal VPA exposure also increased behavioral despair and reduced working and recognition memory in male offspring. Although prenatal VPA increased hippocampal IL-6 and IFN-γ, and prefrontal IFN-γ and IL-17 in males, it only increased hippocampal TNF-α and IFN-γ in female offspring. Adolescent exercise made VPA-treated male and female offspring resistant to anxiety-and anhedonia-like behavior in adulthood, whereas it only made VPA-exposed male offspring resistant to behavioral despair, social and cognitive deficits in adulthood. Exercise reduced hippocampal IL-6, TNF-α, IFN-γ, and IL-17, and prefrontal IFN-γ and IL-17 in VPA-treated male offspring, whereas it reduced hippocampal TNF-α and IFN-γ in VPA-treated female offspring. This study suggests that adolescent exercise may prevents the development of stress-related symptoms, cognitive deficits, and neuroinflammation in prenatally VPA-exposed offspring mice.

Diazepam and exercise training combination synergistically reduces lipopolysaccharide-induced anxiety-like behavior and oxidative stress in the prefrontal cortex of mice

Anxiety-related disorders are among the most important risks for global health, especially in recent years due to the COVID-19 pandemic. Benzodiazepines like diazepam are generally used to treat anxiety disorders, but the overall outcome is not always satisfactory. This is why psychiatrists encourage patients with anxiety to change their lifestyle habits to decrease the risk of anxiety recurrence. However, the effect of diazepam and exercise in combination is unknown. This study aimed to investigate the effect of diazepam alone or in combination with swimming exercise on lipopolysaccharide (LPS)-induced anxiety-like behavior and oxidative stress in the hippocampus and prefrontal cortex of mice. Mice were exposed to diazepam and swimming exercise alone or in combination with each other and then received LPS. We assessed anxiety-like behavior using open field and light-dark box and measured oxidative markers including glutathione (GSH), malondialdehyde (MDA), and glutathione disulfide (GSSG) in the hippocampus and prefrontal cortex. The findings showed that LPS increased anxiety-related symptoms and oxidative stress by decreasing GSH and increasing MDA and GSSG levels in the prefrontal cortex but not in the hippocampus. Although diazepam alone did not reduce anxiety-like behavior and oxidative stress, it in combination with exercise significantly decreased anxiety-like behavior and oxidative stress in the prefrontal cortex of LPS-treated mice. This drug and exercise combination also displayed a more effective effect in comparison with exercise alone. Overall, this study suggests that diazepam in combination with swimming exercise has higher efficacy on anxiety-like behavior and oxidative stress than when they are used alone.

The role of the oxytocinergic system in the antidepressant-like effect of swimming training in male mice

Increasing evidence shows that higher physical activity such as running and swimming exercises is associated with decreased depression-related symptoms. However, underlying mechanisms are not fully understood. This study aimed to investigate whether oxytocinergic system can mediate the antidepressant effect of swimming exercises in mice. First, male NMRI mice were subjected to swimming training for eight weeks, then animals intraperitoneally received oxytocin antagonist (L-368899) 1hour before behavioral tests. We assessed anhedonia and social behavior and behavioral despair using the sucrose preference test, social interaction test, and tail suspension test. Oxytocin levels in the brain and serum were also measured. The results showed that swimming training decreased anhedonia and behavioral despair, whereas it increased social behavior and oxytocin levels in male mice. On the other hand, a subthreshold dose of oxytocin antagonist treatment in exercised mice prevented the antidepressant effect of swimming exercise via increased anhedonia and behavioral despair and decreased social behavior compared to the swimming training group. However, the blockade of oxytocin receptors did not affect oxytocin levels in exercised mice. Overall, these findings suggest that oxytocinergic system can play a role in mediating the antidepressant-like effect of swimming training in mice.

Outrunning a bad diet: interactions between exercise and a Western-style diet for adolescent mental health, metabolism and microbes

Adolescence is a period of biological, psychological and social changes, and the peak time for the emergence of mental health problems. During this life stage, brain plasticity including hippocampal neurogenesis is increased, which is crucial for cognitive functions and regulation of emotional responses. The hippocampus is especially susceptible to environmental and lifestyle influences, mediated by changes in physiological systems, resulting in enhanced brain plasticity but also an elevated risk for developing mental health problems. Indeed, adolescence is accompanied by increased activation of the maturing hypothalamic-pituitary-adrenal axis, sensitivity to metabolic changes due to increased nutritional needs and hormonal changes, and gut microbiota maturation. Importantly, dietary habits and levels of physical activity significantly impact these systems. In this review, the interactions between exercise and Western-style diets, which are high in fat and sugar, on adolescent stress susceptibility, metabolism and the gut microbiota are explored. We provide an overview of current knowledge on implications of these interactions for hippocampal function and adolescent mental health, and speculate on potential mechanisms which require further investigation.

The effect of 4-Week rehabilitation by aerobic exercise on hippocampus BDNF and TGF-β1 gene expressions inAβ 1-42-induced rat model of Alzheimer's disease

Alzheimer's disease (AD) is a type of brain dysfunction featuring a gradual loss in memory. This study aimed to determine the effect of 4 weeks of aerobic rehabilitation exercise (RhExe) on the genes expression of BDNF and TGF-β1 in the hippocampus tissue of rats with the AD induced by injection of amyloid-beta (Aβ_1-42). Twenty-one male Wistar rats were randomly divided into 3 groups: Aβ injection (n = 7), Aβ + exercise (n = 7) and control (n = 7). AD was induced by a single dose of Aβ injection into the hippocampus of rats. Three days after surgery, the Aβ + exercise group experienced four weeks of the RhExe (5 days/week). Forty-eight hours after the last training session, the animals underwent the Morris water maze test. The animals were sacrificed 24 h after the test, and hippocampal tissue was split. The mRNA expression of BDNF, TGF-β1, and TGF-β1 II receptors was measured. The TGF-β1 and TGF-β1 II receptor genes expression of Aβ + exercise group were significantly higher than the Aβ injection group (P ≤ 0.001). BDNF gene expression in the hippocampus of the Aβ + exercise group was significantly higher than the Aβ injection group (P ≤ 0.001). Spatial memory was significantly higher in the Aβ + exercise group than in the Aβ injection group (p ≤ 0.01). It seems that aerobic exercise can counteract the harmful effects of Aβ through the BDNF and TGF-β1molecular signaling pathways.

Treadmill exercise sex-dependently alters susceptibility to depression-like behaviour, cytokines and BDNF in the hippocampus and prefrontal cortex of rats with sporadic Alzheimer-like disease

Alzheimer's disease (AD) is associated with increased depression-related behaviours. Previous studies have reported a greater risk of AD and depression in women. In recent years, we and others have provided evidence that exercise during life could be used as a therapeutic strategy for stress-related disorders such as depression. The main goal of the current study was to determine whether treadmill exercise during life can reduce depression-related behaviours in male and female Wistar rats with sporadic Alzheimer-like disease (ALD). Animals were subjected to treadmill exercise eight weeks before and four weeks after ALD induction by streptozocin (STZ). We measured body weight, food intake, and depression-related symptoms in rats using five behavioural tests. We measured brain-derived-neurotrophic factor (BDNF), tumour-necrosis factor (TNF)-α, and interleukin (IL)-10 levels in the hippocampus and prefrontal cortex of animals. Our findings showed that exercise but not ALD induction decreased body weight and food intake in male and female rats. ALD induction increased depression-related symptoms and hippocampal TNF-α in male and female rats. Besides, treadmill exercise alone decreased depression-related behaviours and increased hippocampal BDNF in females but not males. We also found that treadmill exercise decreased depression-related behaviours and TNF-α in the hippocampus and prefrontal cortex, and increased IL-10 in the prefrontal cortex and BDNF in the hippocampus of female ALD-induced rats. However, treadmill exercise only reduced anhedonia-like behaviour and hippocampal TNF-α in male ALD-induced rats. Overall, the evidence from this study suggests that treadmill exercise alters depression-related behaviours, brain BDNF and cytokines in a sex-dependant manner in rats with sporadic Alzheimer-like disease.

Swimming exercise decreases depression-like behaviour and inflammatory cytokines in a mouse model of type 2 diabetes

NEW FINDINGS

What is the central question of this study? Can swimming exercise decrease depression-like behaviour and inflammation in type 2 diabetic mice? What is the main finding and its importance? Swimming exercise decreased depression-like behaviour by reducing inflammation in type 2 diabetic mice. Swimming exercise might be useful for the treatment of depression-related disorders in patients with type 2 diabetes.

ABSTRACT

Clinical and experimental studies have shown that type 2 diabetes is associated with depression-related disorders. Inflammation has been identified as a common mechanism in both type 2 diabetes and depression. Several studies have suggested that swimming exercise might be able to reduce depression-related symptoms. The present study aimed to explore whether swimming exercise can decrease depression-like behaviour in type 2 diabetic mice. To induce type 2 diabetes, male C57BL6 mice were treated with a high-fat diet and streptozocin. Type 2 diabetic animals were subjected to swimming exercise for 4 weeks. Then, depression-like behaviours were evaluated by sucrose preference, novelty-suppressed feeding, social interaction and tail suspension tests. We also measured levels of glucose, insulin and pro-inflammatory cytokines such as interleukin-1β and tumour necrosis factor-α in the serum of animals. The results indicated that type 2 diabetes significantly increased anhedonia- and depression-like behaviours in mice. We also found significant increases in glucose, insulin and inflammatory cytokines in diabetic mice. Moreover, swimming exercise reduced anhedonia- and depression-like behaviour in type 2 diabetic mice. Swimming exercise also decreased glucose and inflammatory cytokines in the serum of mice with type 2 diabetes. Collectively, this study demonstrates that swimming exercise decreased depression-like behaviour by reducing inflammation in type 2 diabetic mice. Further clinical studies are needed to validate these findings in patients with type 2 diabetes.

Swimming exercise attenuates anxiety-like behavior by reducing brain oxidative stress in type 2 diabetic mice

Anxiety-related behaviors are among the most prevalent psychiatric disorders in patients with type 2 diabetes (T2D). The protective effect of exercise on neuropsychiatric disorders has been documented. However, there are no studies that examined whether swimming exercise can decrease anxiety-like symptoms in type 2 diabetes. We investigated the effects of swimming exercise on body weight, anxiety-like behavior, glucose and insulin levels, and brain oxidative stress in male C57BL/6 mice. T2D-induced mice were subjected to swimming exercise, then anxiety-like behaviors were measured by the open field, light-dark box, and elevated plus-maze tests. Glucose and insulin levels were measure in serum, and antioxidant/oxidative markers including glutathione (GSH), malondialdehyde (MDA), and glutathione disulfide (GSSG) were measured in the brain. Our findings showed that T2D increased body weight, anxiety-like symptoms, glucose and insulin resistance, and oxidative stress by increasing MDA and GSSG levels in the brain of mice. Interestingly, swimming exercise reversed these parameters in diabetic mice. Our findings clearly indicate that there is a protective impact of swimming exercise on anxiety-like behavior by reducing insulin resistance and brain oxidative stress in mice with type 2 diabetes. Further studies are needed to validate these findings in humans.

A Runner's High for New Neurons? Potential Role for Endorphins in Exercise Effects on Adult Neurogenesis

Physical exercise has wide-ranging benefits to cognitive functioning and mental state, effects very closely resembling enhancements to hippocampal functioning. Hippocampal neurogenesis has been implicated in many of these mental benefits of exercise. However, precise mechanisms behind these effects are not well known. Released peripherally during exercise, beta-endorphins are an intriguing candidate for moderating increases in neurogenesis and the related behavioral benefits of exercise. Although historically ignored due to their peripheral release and status as a peptide hormone, this review highlights reasons for further exploring beta-endorphin as a key mediator of hippocampal neurogenesis. This includes possible routes for beta-endorphin signaling into the hippocampus during exercise, direct effects of beta-endorphin on cell proliferation and neurogenesis, and behavioral effects of manipulating endogenous opioid signaling. Together, beta-endorphin appears to be a promising mechanism for understanding the specific ways that exercise promotes adult neurogenesis specifically and brain health broadly.

Perinatal fluoxetine dose-dependently affects prenatal stress-induced neurobehavioural abnormalities, HPA-axis functioning and underlying brain alterations in rat dams and their offspring

Both untreated and SSRI antidepressant treated maternal depression during the perinatal period can pose both short-and long-term health risks to the offspring. Therefore, it is essential to have an effective SSRI treatment consisting of the lowest effective dose beneficial to the mother, without causing adverse effects on offspring development. The effects of prenatal stress on neurobehavioral outcomes were studied in the pregnant and lactating rat dam, and her offspring. Furthermore, stressed dams were treated with different doses of fluoxetine (FLX; 5, 10and 25 mg/kg) during pregnancy and the postpartum period. We found that prenatal stress-induced anxiety-and depressive-like behaviour and increased HPA-axis function in pregnant and postpartum dams, and in offspring. Maternal stress impaired object recognition but did not affect spatial memory in offspring. Prenatal stress decreased whole-brain serotonin and brain-derived-neurotrophic-factor, and increased interleukin-17 and malondialdehyde, but did not affect oxytocin and interleukin-6 in the brains of offspring. Maternal treatment with 5 mg/kg FLX during the perinatal period did not rescue any stress-induced anxiety/depressive-like behaviour in the pregnant and postpartum dam and had only a few rescuing effects in offspring. Maternal FLX treatment with 10 mg/kg did rescue most stress-induced anxiety-and depressive-like behaviour or HPA-axis-function in dams and offspring. The highest dose tested, 25 mg/kg FLX, had the rescuing properties in dams while having the same, or an even greater, detrimental effect as prenatal stress on offspring behaviour and molecular alterations in the brain. Our results show prenatal stress rescuing properties for FLX treatment in the pregnant and postpartum dam, with dose-dependent effects on the offspring.

Environmental enrichment alters neurobehavioral development following maternal immune activation in mice offspring with epilepsy

Epilepsy is a chronic brain disease affecting millions of people worldwide. Anxiety-related disorders and cognitive deficits are common in patients with epilepsy. Previous studies have shown that maternal infection/immune activation renders children more vulnerable to neurological disorders later in life. Environmental enrichment has been suggested to improve seizures, anxiety, and cognitive impairment in animal models. The present study aimed to explore the effects of environmental enrichment on seizure scores, anxiety-like behavior, and cognitive deficits following maternal immune activation in offspring with epilepsy. Pregnant mice were treated with lipopolysaccharides-(LPS) or vehicle, and offspring were housed in normal or enriched environments during early adolescence to adulthood. To induce epilepsy, adult male and female offspring were treated with Pentylenetetrazol-(PTZ), and then anxiety-like behavior and cognitive functions were assessed. Tumor-necrosis-factor (TNF)-α and interleukin (IL) 10 were measured in the hippocampus of offspring. Maternal immune activation sex-dependently increased seizure scores in PTZ-treated offspring. Significant increases in anxiety-like behavior, cognitive impairment, and hippocampal TNF-α and IL-10 were also found following maternal immune activation in PTZ-treated offspring. However, there was no sex difference in these behavioral abnormalities in offspring. Environmental enrichment reversed the effects of maternal immune activation on behavioral and inflammatory parameters in PTZ-treated offspring. Overall, the present findings highlight the adverse effects of prenatal maternal immune activation on seizure susceptibility and psychiatric comorbidities in offspring. This study suggests that environmental enrichment may be used as a potential treatment approach for behavioral abnormalities following maternal immune activation in PTZ-treated offspring.