Prenatal Exposure to Classical Music Improves Learning and Memory in Adult Rats

Background: Exposure to music during pregnancy enhances brain development and improves learning in neonatal rats. Methods: In these experiments, we examined the effects of exposure to silence, hard rock, classical, and rap music in utero plus 60 days postpartum on learning and memory in adult Wistar rats. Passive avoidance learning (PAL) was assessed at age 60 days, and a retention test was done 24 hours after training. Elevated plus maze (EPM) was also used as a standard behavioral task for assessing the effects of music therapy on anxiety. Furthermore, we measured serum corticosterone levels and adrenal weight at the end of experiments to show the possible effect of stress on the rats’ behavior. Results: Hard rock music impaired acquisition, increasing the number of trials to acquisition in PAL task. Hard rock music also impaired the retrieval process by decreasing step-through latency and increasing time spent in the dark compartment during the retention trial. Further, in the hard rock group, there were increases in serum corticosterone and adrenal weight of rats. Classical music, in turn, improved acquisition learning and retention memory and decreased serum corticosterone levels compared to the silence group. Rats’ exposure to rap music did not show any significant change in acquisition and retrieval processes compared to the silence group. In the EPM task, classical music exposure had anxiolytic-like effects revealed in an increase in the number of entries into open arms and time spent in the open arms. However, in this task, hard rock music induced an anxiogenic effect. Conclusions: Prenatal and postnatal exposure to music improves PAL and memory in adult rats. The effects of music therapy with classical music might be related to stress reduction by lowering corticosterone as a stress biomarker or anxiolytic effects; this deserves further examination.

Social isolation induces neuroinflammation and microglia overactivation, while dihydromyricetin prevents and improves them

Background Anxiety disorders are the most prevalent mental illnesses in the U.S. and are estimated to consume one-third of the country’s mental health treatment cost. Although anxiolytic therapies are available, many patients still exhibit treatment resistance, relapse, or substantial side effects. Further, due to the COVID-19 pandemic and stay-at-home order, social isolation, fear of the pandemic, and unprecedented times, the incidence of anxiety has dramatically increased. Previously, we have demonstrated dihydromyricetin (DHM), the major bioactive flavonoid extracted from Ampelopsis grossedentata, exhibits anxiolytic properties in a mouse model of social isolation-induced anxiety. Because GABAergic transmission modulates the immune system in addition to the inhibitory signal transmission, we investigated the effects of short-term social isolation on the neuroimmune system. Methods Eight-week-old male C57BL/6 mice were housed under absolute social isolation for 4 weeks. The anxiety-like behaviors after DHM treatment were examined using elevated plus-maze and open field behavioral tests. Gephyrin protein expression, microglial profile changes, NF-κB pathway activation, cytokine level, and serum corticosterone were measured. Results Socially isolated mice showed increased anxiety levels, reduced exploratory behaviors, and reduced gephyrin levels. Also, a dynamic alteration in hippocampal microglia were detected illustrated as a decline in microglia number and overactivation as determined by significant morphological changes including decreases in lacunarity, perimeter, and cell size and increase in cell density. Moreover, social isolation induced an increase in serum corticosterone level and activation in NF-κB pathway. Notably, DHM treatment counteracted these changes. Conclusion The results suggest that social isolation contributes to neuroinflammation, while DHM has the ability to improve neuroinflammation induced by anxiety.

Neonatal action of the dipeptidyl peptidase iv inhibitor diprotin A leads to a hyperactive phenotype formation and a prolonged increase in aggressiveness in rats

Введение. Ингибиторы пролинспецифической сериновой протеазы дипептидилпептидазы IV (ДПП-IV, CD26, EC 3.4.14.5), способные модулировать широкий спектр физиологических процессов, находят применение в клинике. В наших работах получены свидетельства влияния ингибиторов ДПП-IV при их введении в раннем постнатальном периоде на эмоционально-мотивационное поведение взрослых крыс. Более сильные изменения в поведении отмечались у крыс при действии ингибитора ДПП-IV дипротина А. Однако не ясно, как долго сохраняются такие изменения. Цель работы - изучение отсроченных эффектов ингибитора ДПП-IV дипротина А на выраженность эмоционально-мотивационных расстройств, индуцированных действием ингибитора в раннем постнатальном периоде, в динамике взросления крыс от 2 до 7 мес. Методика. Дипротин А вводили крысятам ежедневно в 5-18-й постнатальные дни внутрибрюшинно (2 мг/кг), в объеме 0.1 мл на 10 г массы тела. Крысята контрольной группы получали инъекции физиологического раствора. Поведение взрослых крыс оценивали в возрасте 2 и 7 мес в тестах автоматизированного «открытого поля», «Приподнятый крестообразный лабиринт» (ПКЛ), принудительного плавания и социального взаимодействия. Уровень кортикостерона в сыворотке крови определяли методом твердофазного иммуноферментного анализа ELISA. Для статистической обработки результатов использовали двухфакторный дисперсионный анализ Two Way ANOVA и непараметрический U-критерий Манна-Уитни с поправкой на множественность сравнений. Результаты. У крыс опытной группы по сравнению с контрольной группой в возрасте 2 и 7 мес была повышена двигательная активность и скорость перемещения в тесте ПКЛ. В возрасте 7 мес у них также была увеличена вертикальная исследовательская активность. Признаков повышения тревожности не выявлено. У крыс опытной группы выявлены признаки депрессивно-подобного поведения по нарушению биоритмологической структуры плавания, более выраженные в возрасте 7 мес. Неагрессивное социальное взаимодействие у крыс, получавших неонатально дипротин А, было снижено по сравнению с контролем в возрасте 2 мес, а в возрасте 7 мес, напротив, увеличено. У этих животных число и длительность агрессивных социальных контактов были увеличены по сравнению с контролем как в возрасте 2, так и в возрасте 7 мес. Уровень кортикостерона в сыворотке крови у крыс опытной группы в возрасте 7.5 мес был выше, чем в контроле. Заключение. Данные настоящего исследования свидетельствуют о развитии гиперактивного фенотипа и длительных психоэмоциональных нарушений в виде повышенной агрессивности наряду с активацией гипоталамо-гипофизарно-адреналовой оси у взрослых крыс, подвергнутых действию дипротина А в 5-18-й постнатальные дни, и поддерживают представления об участии дипептидилпептидазы-IV в генезе психоэмоциональных расстройств. Background. Inhibitors of the proline-specific serine protease dipeptidyl peptidase IV (DPP-IV, CD26, EC 3.4.14.5) may modulate a wide range of physiological processes and are used in the clinic. In our studies, we obtained evidence for the impact of DPP-IV inhibitors on adult rats’ emotional and motivational behavior when administered in the early postnatal period. Diprotin A exhibited the most significant impact on the animals’ behaviors. However, it is not clear how long the changes persist. Aim. To study the delayed effects of the DPP-IV inhibitor diprotin A on the severity of emotional and motivational disorders induced by the inhibitor action in the early postnatal period, in the dynamics of rats maturation from 2 to 7 months. Methods. Diprotin A was administered to rat pups daily on postnatal days 5-18, intraperitoneally, at a dose of 2 mg/kg, in a volume of 0.1 ml per 10 g of body weight. The rat pups of the control group received saline. The behavior of adult rats was assessed at the age of 2 and 7 months in the automated “open field,” “Elevated Plus Maze” (EPM), forced swimming, and social interaction tests. Serum corticosterone levels were determined by ELISA. The results were statistically processed using Two Way ANOVA and nonparametric Mann-Whitney U-test adjusted for multiple comparisons. Results. Experimental rats increased motor activity and travel speed in the EPM test compared with the control group at 2 and 7 months of age. At the age of 7 months, experimental rats also increased vertical (rearing) activity. There were no signs of increased anxiety. Experimental rats demonstrated depression-like behavior judged by the biorhythmologic structure of swimming, more pronounced at 7 months. Non-aggressive social interaction in rats treated neonatally with diprotin A was reduced compared with controls at the age of 2 months and, on the contrary, increased at the age of 7 months. In these animals, the number and duration of aggressive social contacts were increased compared with controls at the ages of 2 and 7 months. Serum corticosterone levels in experimental rats at the age of 7.5 months were higher than in control. Conclusion. The present study results testify to the development of a hyperactive phenotype and prolonged psychoemotional disorders as increased aggressiveness along with hypothalamic-pituitary-adrenal axis activation in adult rats exposed to the action of diprotin A on postnatal days 5-18. The data support the dipeptidyl peptidase IV involvement in the genesis of psychoemotional disorders.

Stress Response and Hearing Loss Differentially Contribute to Dynamic Alterations in Hippocampal Neurogenesis and Microglial Reactivity in Mice Exposed to Acute Noise Exposure

Noise-induced hearing loss (NIHL) is one of the most prevalent forms of acquired hearing loss, and it is associated with aberrant microglial status and reduced hippocampal neurogenesis; however, the nature of these associations is far from being elucidated. Beyond its direct effects on the auditory system, exposure to intense noise has previously been shown to acutely activate the stress response, which has increasingly been linked to both microglial activity and adult hippocampal neurogenesis in recent years. Given the pervasiveness of noise pollution in modern society and the important implications of either microglial activity or hippocampal neurogenesis for cognitive and emotional function, this study was designed to investigate how microglial status and hippocampal neurogenesis change over time following acoustic exposure and to analyze the possible roles of the noise exposure-induced stress response and hearing loss in these changes. To accomplish this, adult male C57BL/6J mice were randomly assigned to either a control or noise exposure (NE) group. Auditory function was assessed by measuring ABR thresholds at 20 days post noise exposure. The time-course profile of serum corticosterone levels, microglial status, and hippocampal neurogenesis during the 28 days following noise exposure were quantified by ELISA or immunofluorescence staining. Our results illustrated a permanent moderate-to-severe degree of hearing loss, an early but transient increase in serum corticosterone levels, and time-dependent dynamic alterations in microglial activation status and hippocampal neurogenesis, which both present an early but transient change and a late but enduring change. These findings provide evidence that both the stress response and hearing loss contribute to the dynamic alterations of microglia and hippocampal neurogenesis following noise exposure; moreover, noise-induced permanent hearing loss rather than noise-induced transient stress is more likely to be responsible for perpetuating the neurodegenerative process associated with many neurological diseases.

Social Isolation Induces Neuroinflammation And Microglia Overactivation, While Dihydromyricetin Prevents And Improves Them.

Background: Anxiety disorders are the most prevalent mental illnesses in the U.S. and are estimated to consume one-third of the country's mental health treatment cost. Although anxiolytic therapies are available, many patients still exhibit treatment-resistance, relapse, or substantial side effects. Further, due to the COVID-19 pandemic and stay-at-home order, social isolation, fear of the pandemic, and unprecedented times, the incidence of anxiety has dramatically increased. Previously, we have demonstrated dihydromyricetin (DHM), the major bioactive flavonoid extracted from Ampelopsis grossedentata, exhibits anxiolytic properties in a mouse model of social isolation-induced anxiety. Because GABAergic transmission modulates the immune system in addition to the inhibitory signal transmission, we investigated the effects of short-term social isolation on the neuroimmune system.Methods: Eight-week-old male C57BL/6 mice were housed under absolute social isolation for 4 weeks. The anxiety like behaviors after DHM treatment were examined using elevated plus maze and open field behavioral tests. Gephyrin protein expression, microglial profile changes, NF-κB pathway activation, cytokine level, and serum corticosterone were measured. Results: Socially isolated mice showed increased anxiety levels, reduced exploratory behaviors, and reduced gephyrin levels. Also, a dynamic alteration in hippocampal microglia were detected illustrated as a decline in microglia number and overactivation as determined by significant morphological changes including decreases in lacunarity, perimeter, and cell size and increase in cell density. Moreover, social isolation also induced an increase in serum corticosterone level and activation in NF-κB pathway. Notably, DHM treatment counteracted these changes.Conclusion: The results suggest that social isolation contributes to neuroinflammation, while DHM has the ability to restore neuroinflammatory changes induced by anxiety.

Binge Alcohol Disrupts Skeletal Muscle Core Molecular Clock Independent of Glucocorticoids

Circadian rhythms are central to optimal physiological function as disruption contributes to the development of several chronic diseases. Alcohol (EtOH) intoxication disrupts circadian rhythms within liver, brain, and intestines, but it is unknown whether alcohol also disrupts components of the core clock in skeletal muscle. Female C57BL/6Hsd mice were randomized to receive either saline (control) or alcohol (EtOH) (5g/kg) via intraperitoneal injection at the start of the dark cycle (ZT12), and gastrocnemius was collected every 4hr from Control and EtOH treated mice for the next 48hr following isoflurane anesthetization. In addition, metyrapone was administered prior to alcohol intoxication in separate mice to determine whether the alcohol-induced increase in serum corticosterone contributed to circadian gene regulation. Finally, synchronized C2C12 myotubes were treated with alcohol (100mM) to assess the influence of centrally or peripherally mediated effects of alcohol on the muscle clock. Alcohol significantly disrupted mRNA expression of Bmal1, Per1/2, and Cry1/2 in addition to perturbing the circadian pattern of clock-controlled genes, Myod1, Dbp, Tef, and Bhlhe40 (p<0.05) in muscle. Alcohol increased serum corticosterone levels and glucocorticoid target gene, Redd1, in muscle. Metyrapone prevented the EtOH-mediated increase in serum corticosterone but did not normalize the EtOH-induced change in Per1, Cry1 and Cry2 and Myod1 mRNA expression. Core clock gene expression (Bmal, Per1/2, Cry1/2) was not changed following 4, 8, or 12hrs of alcohol treatment on synchronized C2C12 myotubes. Therefore, binge alcohol disrupted genes of the core molecular clock independently of elevated serum corticosterone or direct effects of EtOH on the muscle.

Health Status and Stress in Different Categories of Racing Pigeons

The influence of different stress parameters in racing pigeon flocks, such as the presence of diseases and environmental conditions at the time of the races, were described. A total of 96 racing pigeons from 4 pigeon flocks were examined, and health monitoring was carried out. No helminth eggs and coccidia were found. Trichomonas sp. was confirmed in subclinical form. Paramyxoviruses and avian influenza viruses were not confirmed, but circovirus infections were confirmed in all flocks. Chlamydia psittaci was confirmed in one flock. Blood samples were collected, and HI antibody titers against paramyxoviruses before and 25 days after vaccination were determined. To improve the conditions during racing and the welfare of the pigeons, critical points were studied with regard to stress factors during the active training season. Serum corticosterone levels were measured in the blood serum of four different categories of pigeons from each flock. Corticosterone levels were almost twice as high in pigeons from the category that were active throughout the racing season, including medium- and long-distance racing, compared to the other three categories that were not racing actively. Within five hours of the finish of a race, the average serum corticosterone level was 59.4 nmol/L in the most physically active category. The average serum corticosterone level in this category remained at 37.5 nmol/L one month after the last race.

Vestibular Stimulation as An Interventional Approach for Cold Water Stress Induced Immunological and Histopathological Changes in Rats

Background: Chronic exposure to stress results in immuno-suppression. The present study was carried out to explore the therapeutic benefits of vestibular stimulation on the immune system of stress-induced Wistar rats. Methods: Stress was intervened in the Wistar rats by cold water swimming method for a period of 14 days. Following stress, caloric vestibular stimulation was induced in the rats by irrigating external auditory meatus bilaterally with hot water (temperature 41oC) for 2 minutes for a period of 15 days and 30 days in respective groups. At the end of the experiment, blood samples were obtained and serum corticosterone, Interleukin 2 (IL2), Immunoglobulin M (IgM) levels were analyzed using ELISA method and histopathology of brain was assessed. Brain CD4 and CD8 cells were analyzed by Immunohistochemistry. Result: Stress significantly increased serum corticosterone, IL2 levels and reduced IgM levels. Stress group showed increased dendritic arborization in prefrontal cortex, neuronal atrophy, nuclear pyknosis with congested blood vessels in hippocampus and mononuclear cell inflammatory infiltrate in hypothalamus. Brain extravascular CD4 and CD8 showed positive in stress group. Caloric vestibular stimulation effectively reduced serum corticosterone levels, histopathological changes, brain extravascular CD4 and CD8 cells and improved IgM in the present study.

Corticosterone Can Be an Essential Stress Index in Channel Catfish (Ictalurus punctatus)

Although cortisol is considered the main glucocorticoid involved in regulating stress in fish by elevating the serum glucose, the presence of serum corticosterone and whether its level can be used as an indicator for fish stress activation and reflect the degree of fish stress remains to be determined. To comprehensively and accurately evaluate the performance of two glucocorticoids after stress, in this study, seven of the most common stressors (ammonia nitrogen, high-temperature, acid, alkali, Aeromonas hydrophila, and salinity) in aquaculture were selected. The levels of serum corticosterone, cortisol, and glucose were detected within 48 h, and then the dynamic changes were analyzed. In addition, the kidneys were collected to detect the expression of corresponding proteins involved in corticosterone and cortisol synthesis (3 β-HSD and CYP17A1) for further exploration. From the results obtained, the content of serum corticosterone was about 100 times higher than that of cortisol, and it was found that corticosterone and cortisol showed different dynamic changes within 48 h among the seven kinds of stress. In the subsequent detection of glucose, it was found that the dynamic shift in glucose was not consistent with the dynamic changes of corticosterone or cortisol entirely but seemed to be caused by the combination of the two. In the follow-up protein expression detection, we found that corticosterone seemed to respond to stress earlier. Therefore, it is concluded that the responses of corticosterone and cortisol to stress are independent, corticosterone may be more sensitive in the current seven acute stresses, and then they regulate glucose together to resist stress. The study aimed to fill the vacancy of corticosterone in fish research and provide a reference for the complete evaluation of fish stress degree.