Subdividing Stress Groups into Eustress and Distress Groups Using Laterality Index Calculated from Brain Hemodynamic Response

A stress group should be subdivided into eustress (low-stress) and distress (high-stress) groups to better evaluate personal cognitive abilities and mental/physical health. However, it is challenging because of the inconsistent pattern in brain activation. We aimed to ascertain the necessity of subdividing the stress groups. The stress group was screened by salivary alpha-amylase (sAA) and then, the brain’s hemodynamic reactions were measured by functional near-infrared spectroscopy (fNIRS) based on the near-infrared biosensor. We compared the two stress subgroups categorized by sAA using a newly designed emotional stimulus-response paradigm with an international affective picture system (IAPS) to enhance hemodynamic signals induced by the target effect. We calculated the laterality index for stress (LIS) from the measured signals to identify the dominantly activated cortex in both the subgroups. Both the stress groups exhibited brain activity in the right frontal cortex. Specifically, the eustress group exhibited the largest brain activity, whereas the distress group exhibited recessive brain activity, regardless of positive or negative stimuli. LIS values were larger in the order of the eustress, control, and distress groups; this indicates that the stress group can be divided into eustress and distress groups. We built a foundation for subdividing stress groups into eustress and distress groups using fNIRS.

Modeling Brain Dynamics During Virtual Reality-Based Emergency Response Learning Under Stress

Background Stress affects learning during training, and virtual reality (VR) based training systems that manipulate stress can improve retention and retrieval performance for firefighters. Brain imaging using functional Near Infrared Spectroscopy (fNIRS) can facilitate development of VR-based adaptive training systems that can continuously assess the trainee’s states of learning and cognition. Objective The aim of this study was to model the neural dynamics associated with learning and retrieval under stress in a VR-based emergency response training exercise. Methods Forty firefighters underwent an emergency shutdown training in VR and were randomly assigned to either a control or a stress group. The stress group experienced stressors including smoke, fire, and explosions during the familiarization and training phase. Both groups underwent a stress memory retrieval and no-stress memory retrieval condition. Participant’s performance scores, fNIRS-based neural activity, and functional connectivity between the prefrontal cortex (PFC) and motor regions were obtained for the training and retrieval phases. Results The performance scores indicate that the rate of learning was slower in the stress group compared to the control group, but both groups performed similarly during each retrieval condition. Compared to the control group, the stress group exhibited suppressed PFC activation. However, they showed stronger connectivity within the PFC regions during the training and between PFC and motor regions during the retrieval phases. Discussion While stress impaired performance during training, adoption of stress-adaptive neural strategies (i.e., stronger brain connectivity) were associated with comparable performance between the stress and the control groups during the retrieval phase.

A Terrified Sound Stress Impairs Learning And Memory Ability of Adult Female

Stress, as an important environmental factor of mental health, cannot be ignored. The great physiological difference between males and females implies that the effects of stress may differ by gender. However, few studies have focused on the effects of stress on females. This study investigated the effects of a terrified sound stress on adult female mice.Methods: 32 adults female C57BL/6 mice were randomly divided into control group (n=16) and stress group (n=16). Sucrose preference test and open field test (OFT) were carried out to evaluate the anxiety and depression of mice. Spatial learning and memory ability were measured by Morris Water maze test (MWM). Endocrine hormones were determined by enzyme-linked immunosorbent assay (ELISA). Serum differential proteins were screened by mass spectrometry (MS). Results: Compared with control group, the sucrose preference of stress group was decreased; in MWM, the escape latency of the stress group was significantly prolonged (P<0.05), and the total swimming distance was significantly increased (P<0.05).Serum T (P<0.05), GnRH (P<0.05), FSH and LH levels decreased; thirty six differential peaks were found by MS, eight of them had high multiples of difference (> 1.2 or <0.8). Conclusion: terrified sound stress impairs spatial learning ability and mental health of adult female mice.

Effects of Treadmill Exercise on Sexual Behavior and Reproductive Parameters in Chronically Stressed-Male Rats

Exposure to chronic stress stimulates the hypothalamic-pituitary-adrenal (HPA) axis and then simultaneously inhibits hypothalamic-pituitary-gonadal axis (HPG) axis activity. The inhibition formed by the HPA axis is the main mechanism of action of stress on reproductive function. HPG axis activity is known to be changed by various factors, including exercise. Exercise has been found to have a number of positive effects on sexual behavior, reproductive hormones, and sperm parameters in studies with animal models for many years. The main aim of this study is to investigate the effects of chronic treadmill exercise on chronically stressed-male rats’ sexual behavior, reproductive hormones, and sperm parameters. A total of 40 sexually adult male rats were randomly and equally divided into four groups as control, stress, exercise, and stress+exercise. Animals in the exercise group were subjected to the chronic treadmill exercise (moderate intensity) for 33 days with a periodic increase in speed and duration. Animals in the stress group were exposed to restraint stress for 1 h, 2 h, and 3 h during the first, second and third 15 days respectively. Sexual behavior parameters, hormone measurements, and sperm parameters were evaluated. The main effects of chronic exercise on sexual behavior were centered on a significant increase in the ejaculation frequency (EF) in the stress+exercise group. Also, sperm concentration and motility in the stress group significantly decreased, and then sperm motility was improved by exercise in the stress+exercise group. In sum, our results show that chronic treadmill exercise may improve the adverse effects of chronic stress on sexual behavior and sperm parameters in male rats in terms of some parameters.

Chronic heat stress promotes liver inflammation in broilers via enhancing NF-κB and NLRP3 signaling pathway

Background The study was to investigate the effects of chronic heat stress on liver inflammatory injury and its potential mechanisms in broilers. Chickens were randomly assigned to 1-week control group (Control 1), 1-week heat stress group (HS1), 2-week control group (Control 2), and a 2-week heat stress group (HS2) with 15 replicates per group. Broilers in heat stress groups exposed to heat stress (35 ± 2°C) for 8 h/d with 7 or 14 consecutive days. Growth performance and liver inflammation injury were examined for the analysis of liver injury.ResultsThe results showed that heat stress decreased the growth performance, showed obvious blutpunkte, lowered liver weight and liver index, which resulted in significant liver damage of broilers. Both the gene and protein expressions of HSP70, TLR4 and NF-κB in the liver were significantly enhanced by heat stress. Furthermore, heat stress obviously enhanced IL-6, TNF-α, NF-κB P65, IκB and their phosphorylated proteins expressions in the liver of broilers. In addition, heat stress promoted the activation of NLRP3 with increased NLRP3, caspase-1 and IL-1β. ConclusionsThese results suggested that heat stress can cause the liver inflammation via activation of TLR4-NF-κB and NLRP3 signaling pathway in broilers.

Effect of chitosan on blood profile, inflammatory cytokines by activating TLR4/NF-κB signaling pathway in intestine of heat stressed mice

Heat stress can significantly affect the immune function of the animal body. Heat stress stimulates oxidative stress in intestinal tissue and suppresses the immune responses of mice. The protecting effects of chitosan on heat stress induced colitis have not been reported. Therefore, the aim of this study was to investigate the protective effects of chitosan on immune function in heat stressed mice. Mice were exposed to heat stress (40 °C per day for 4 h) for 14 consecutive days. The mice (C57BL/6J), were randomly divided into three groups including: control group, heat stress, Chitosan group (LD: group 300 mg/kg/day, MD: 600 mg/kg/day, HD: 1000 mg/kg/day). The results showed that tissue histology was improved in chitosan groups than heat stress group. The current study showed that the mice with oral administration of chitosan groups had improved body performance as compared with the heat stress group. The results also showed that in chitosan treated groups the production of HSP70, TLR4, p65, TNF-α, and IL-10 was suppressed on day 1, 7, and 14 as compared to the heat stress group. In addition Claudin-2, and Occludin mRNA levels were upregulated in mice receiving chitosan on day 1, 7, and 14 of heat stress. Furthermore, the IL-6, IL-10, and TNF-α plasma levels were down-regulated on day 1, 7, and 14 of heat stress in mice receiving the oral administration of chitosan. In conclusion, the results showed that chitosan has an anti-inflammatory ability to tolerate hot environmental conditions.

Hyperthermia Affects Immune and Oxidative Stress Indices of Immune Organs of Broilers by Changing the Expressions of ABCG2, SVCT-2 and MCU

Background: As global temperatures rise, heat stress has become one of the major environmental stressors in the poultry industry. The purpose of the study was to investigate the effects of heat stress on immune function and oxidative stress, and further reveal the possible mechanisms of oxidative stress induced by heat stress for thymus and spleen of broilers. Methods: At the age of 28 days, thirty broilers were randomly divided into the control group (25 ± 2°C; 24 h/day) and the heat stress group (36 ± 2°C; 8 h/day); the experience was lasted for 1 week. At the end of the experience, the broilers per group were respectively euthanized and collected some samples, then to be analyzed. Results: The results showed that the levels of heat shock proteins 70 (HSP70,P＜ 0.01), corticosterone (CORT,P＜ 0.01), the contents of malondialdehyde (MDA, P＜ 0.05), interleukin-6 (IL-6, P＜ 0.01) and tumor necrosis factor-alpha (TNF-α, P＜ 0.01) in serum were significantly higher in heat stress group than that in the control group; The activities of total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) and contents of glutathione (GSH) in heat stress group significantly reduced (P＜ 0.05) in serum. Compared with the control group, the birds subjected to heat stress reduced the weight (P＜ 0.01) and the indices of thymus (P＜ 0.01), the activities of T-AOC (P＜ 0.01) and SOD (P＜ 0.05) of spleen, and levels of IL-10 (P＜ 0.05) and the GSH-PX (P＜ 0.05) in thymus and spleen, and increased the IL-6 content of thymus (P＜ 0.05), the MDA content (P＜ 0.01), and the reactive oxygen species (ROS) levels (P＜ 0.01) in thymus and spleen. Moreover, the expression of immunoglobulin G (IgG) gene in thymus and spleen of heat stressed broiler significantly increased by reverse transcription-polymerase chain reaction (RT-PCR) and real time RT-PCR (qRT-PCR; P＜ 0.05); However, the expression of immunoglobulin M (IgM) gene in spleen significantly increased (P＜ 0.05), and had no significant difference (P＞ 0.05) in thymus of heat-stressed broiler. Furthermore, the relative expression of ATP binding cassette subfamily G member 2 (ABCG2) in thymus and spleen (P＜ 0.05), sodium dependent vitamin C transporter-2 (SVCT-2, P＜ 0.01) and mitochondria calcium uniporter (MCU, P＜ 0.01) mRNA in thymus of heat stressed broilers significantly increased; and the expression of ABCG2 (P＜ 0.05), SVCT-2 (P＜ 0.01) and MCU (P＜ 0.01) protein of thymus and spleen in the heat-stressed broiler increased significantly compared with the control group. Conclusions: In summary, the study confirmed that heat stress caused oxidative stress to immune organs of broilers, further reduced immune function. Moreover, the potential mechanisms of heat stress-induced oxidative stress for thymus and spleen was further reveal in broilers.

Heat stress modulates polymorphonuclear cell response in early pregnancy cows: I. interferon pathway and oxidative stress

One of the major causes of early pregnancy loss is heat stress. In ruminants, interferon tau (IFNT) is the embryo signal to the mother. Once the interferon signaling pathway is activated, it drives gene expression for interferon-stimulated genes (ISGs) and alters neutrophils responses. The aim of the present study was to evaluate interferon (IFN) pathway, ISGs and gene expression in polymorphonuclear leukocytes (PMN) and oxidative stress in dairy cows under heat stress. Pregnant cows had their estrous cycle synchronized and randomly assigned to a comfort or heat stress group. Blood samples were collected at artificial insemination (AI) and on Days 10, 14 and 18 following AI. Pregnant cows were pregnancy checked by ultrasound on Day 30 and confirmed on Day 60 post-AI. Results are presented as mean ± SEM. The corpus luteum (CL) diameter was not different between groups of pregnant cows; concentration of progesterone of pregnant cows on Day 18 following AI was greater in comfort group compared to heat stressed group. Comfort pregnant cows had higher expression of all analyzed genes from interferon pathway, except for IFNAR1, on both Days 14 and 18. Conversely, heat stressed cows did not show altered expression of IFNT pathway genes and ISGs between Days 10, 14, and 18 after AI. The oxidative stress, determined as malondialdehyde (MDA) levels, was greater in heat stress group on Days 10, 14 and 18, independent of pregnancy status. Heat stress negatively influences expression of ISGs, IFN pathway gene expression in neutrophils, and oxidative stress. Our data suggest that lower conception rates in cows under heat stress are multifactorial, with the association of interferon pathway activation and the unbalanced oxidative stress being main contributing factors.

Identification of functional features underlying heat stress response in Sprague-Dawley rats using mixed linear models

Since global temperature is expected to rise by 2℃ in 2050 heat stress may become the most severe environmental factor. In the study, we illustrate the application of mixed linear models for the analysis of whole transcriptome expression in livers and adrenal tissues of Sprague-Dawley rats obtained by a heat stress experiment. By applying those models, we considered four sources of variation in transcript expression, comprising transcripts (1), genes (2), Gene Ontology terms (3), and Reactome pathways (4) and focussed on accounting for the similarity within each source, which was expressed as a covariance matrix. Models based on transcripts or genes levels explained a larger proportion of log2 fold change than models fitting the functional components of Gene Ontology terms or Reactome pathways. In the liver, among the most significant genes were PNKD and TRIP12. In the adrenal tissue, one transcript of the SUCO gene was expressed more strongly in the control group than in the heat-stress group. PLEC had two transcripts, which were significantly overexpressed in the heat-stress group. PER3 was significant only on gene level. Moving to the functional scale, five Gene Ontologies and one Reactome pathway were significant in the liver. They can be grouped into ontologies related to DNA repair, histone ubiquitination, the regulation of embryonic development and cytoplasmic translation. Linear mixed models are valuable tools for the analysis of high-throughput biological data. Their main advantages are the possibility to incorporate information on covariance between observations and circumventing the problem of multiple testing.

Stress, Emotional Eating and Food Choices Among University Students During the Covid-19

The Covid-19 pandemic has had a huge impact on stress and eating behaviours. This study aims to determine the relationship between stress, emotional eating, and food choices among university students during the Covid-19. A total of 273 university students participated in this cross-sectional study. Online self-administered questionnaires were used to determine the stress intensity, emotional eating, and eating behaviours. All statistical analyses were performed using Statistical Package for the Social Sciences (SPSS). Almost half (49.8%) of the participants experienced high stress. In males, the high-stress group consumed sweets or sugars more frequently than the low-stress group (p<0.05). In females, the high-stress group consumed more sweets or sugar and cakes or cookies but less milk products and fresh fruits than the low-stress group (p<0.05). Students with higher negative emotion scores consumed less cooked vegetables (r=-0.133; p<0.05) whereas students with higher positive emotion scores consumed more fast food (r=0.208; p<0.001), sweets or sugar (r=0.139; p<0.05) and cakes or cookies (r=0.139; p<0.05). Body Mass Index (BMI) was positively correlated with negative emotions (r=0.134; p<0.05), negative situations (r=0.161; p<0.01), and total negative Emotional Appetite Questionnaire (EMAQ) scores (r=0.168; p<0.01). In conclusion, Covid-19 brings negative impact on stress. University students shifted food preferences from healthy foods to palatable foods and this could result in adverse health outcomes. Therefore, stress management interventions and nutrition education should be implemented to reduce stress and overcome stress-induced eating behaviour among private university students during the Covid-19.