Unpredictable chronic prenatal stress and manifestation of generalized anxiety and panic in rat's offspring

[The study of the behavioral reactions and duration of ultrasonic vocalization in rats from females stressed during pregnancy]

OBJECTIVE

To study the psycho-emotional state and its relationship to the duration of ultrasonic vocalization in the offspring of rats with physiological and stress-complicated pregnancy.

MATERIAL AND METHODS

The experiments were performed on the offspring (n=120) of rats with physiological pregnancy and the offspring of animals stressed during the entire gestation period (21-23 days). Study animals were divided into the following groups: 1 - intact - males and females (n=52) born to healthy rats; 2 - stress - males and females (n=68) born to rats that underwent stress during pregnancy.

At the age of 17 days, the total vocalization duration (at 50 kHz) was recorded in rats. To assess the psycho-emotional state of the offspring, the open field and elevated plus maze tests were performed at 22 days, marble burying at 35 days, and Porsolt forced swimming test at 47 days. To assess cognitive function in the offspring, short-term working memory was examined in the recognition of a new object test at 35 days and long-term memory in the conditioned passive avoidance reflex test at the age of 47 days.

RESULTS

The results of the open field and elevated plus maze tests indicated that the offspring of females stressed during pregnancy showed anxious behavior. In addition, animals from stressed rats exhibited compulsive and depressive behaviors in the marble burying and Porsolt forced swimming tests. The offspring of stressed rats showed impaired reproduction of the memory traces in the conditioned passive avoidance reflex test.

CONCLUSION

In the offspring of females stressed during pregnancy, anxious, compulsive, and depressive behavior is observed, accompanied by an increase in the duration of ultrasonic vocalization at 50 kHz.

Prenatal stress induces sex- and tissue-specific alterations in insulin pathway of Wistar rats offspring

BACKGROUND AND AIMS

Prenatal stress may lead to tissue and sex-specific cardiometabolic disorders in the offspring through imbalances in the insulin signaling pathway. Therefore, we aimed to determine the sex-specific adaptations of prenatal stress on the insulin signaling pathway of cardiac and hepatic tissue of adult offspring Wistar rats.

METHODS

Wistar pregnant rats were divided into control and stress groups. Unpredictable stress protocol was performed from the 14th to the 21st day of pregnancy. After lactation, the dams were euthanized and blood was collected for corticosterone measurement and the offspring were separated into four groups according to sex and intervention (n=8/group). At 90 days old, the offspring were submitted to an oral glucose tolerance test (OGTT) and an insulin tolerance test (ITT). After euthanasia blood collection was used for biochemical analysis and the left ventricle and liver were used for protein expression and histological analysis.

RESULTS

Stress increased maternal corticosterone levels, and in the offspring, decreased glucose concentration in both OGTT and ITT, reduced insulin receptor (Irβ) and insulin receptor substrate-1 (IRS1) activation and reduced insulin receptor inhibition (PTP1B) in the liver of male offspring at 90 days old, without repercussions in cardiac tissue. Moreover, female offspring submitted to prenatal stress exhibited reduced fatty acid uptake, with lower hepatic CD36 expression, reduced high density lipoprotein (cHDL) and increased Castelli risk indexes I and II.

CONCLUSIONS

Unpredictable prenatal stress evoked reduced insulin sensitivity and liver-specific impairment in insulin signaling activation in male while increasing markers of cardiovascular risk in females.

Impact of preterm birth on the onset of panic disorder in later life - Results from the Gutenberg Prematurity Study (GPS)

BACKGROUND

The present study aimed to investigate whether prematurity and perinatal stress exert long-term effects on the onset of panic disorder in later life.

METHODS

From 40,189 adults born in Germany between 1969 and 2002, a study cohort (n = 427) stratified by gestational age (GA) (extremely preterm: GA < 29 weeks; very preterm: GA 29-32 weeks; moderately preterm: GA 33-36 weeks; and full-term GA ≥ 37 weeks) was selected (age 28.5 ± 8.7 years). Multivariable logistic regression analyses were conducted to investigate associations between gestational age at birth and panic disorder adjusting for age, gender, socioeconomic status, and perinatal factors.

RESULTS

The prevalence of panic disorder was roughly equal in moderate to very preterm and full-term birth groups at 1.9%-3.8%. However, this rate significantly increased to 14.3% in the extreme preterm category (GA <2 9: 14.3 %, p = 0.002). In multivariable analyses, female gender and GA were independently associated with panic disorder. Adjusting for age, gender and socioeconomic status, panic disorder was associated with lower GA at birth (OR = 1.12 per week (CI95%: 1.01-1.26, p = 0.037). Whereas adjustment for nutrition status or indicators of perinatal stress had no effect, correction for the length of postnatal ICU-stay eliminated the association between preterm birth and later panic disorder.

LIMITATIONS

Limitations include the small number of cases and the reliance on questionnaires to assess mental status.

CONCLUSIONS

Prematurity likely increases the risk of panic disorder later in life, and the subsequent postnatal ICU-stay appears to be of critical importance. However, due to strong collinearity and other associated factors with preterm births, it remains unclear which is the primary determinant.

The hyperexcitability of laterodorsal tegmentum cholinergic neurons accompanies adverse behavioral and cognitive outcomes of prenatal stress

Exposure to prenatal stress (PS) leads to the offspring's vulnerability towards the development of cognitive and behavioral disorders. Laterodorsal tegmentum (LDT) is a part of the brainstem cholinergic system that is believed to play a pivotal role in the stress-associated progression of anxiety, memory impairment, and addictive behaviors. In this study, we aimed to investigate the electrophysiological alterations of LDT cholinergic neurons and its accompanied behavioral and cognitive outcomes in the offspring of mice exposed to physical or psychological PS. Swiss Webster mice were exposed to physical or psychological stress on the tenth day of gestation. Ex vivo investigations in LDT brain slices of adolescent male offspring were performed to evaluate the effects of two stressor types on the activity of cholinergic neurons. Open field test, elevated plus maze, passive avoidance test, and conditioned place preference were conducted to assess behavioral and cognitive alterations in the offspring. The offspring of both physical and psychological PS-exposed mice exhibited increased locomotor activity, anxiety-like behavior, memory impairment, and preference to morphine. In both early- and late-firing cholinergic neurons of the LDT, stressed groups demonstrated higher firing frequency, lower adaptation ratio, decreased action potential threshold, and therefore increased excitability compared to the control group. The findings of the present study suggest that the hyperexcitability of the cholinergic neurons of LDT might be involved in the development of PS-associated anxiety-like behaviors, drug seeking, and memory impairment.

Prenatal chronic stress impairs the learning and memory ability via inhibition of the NO/cGMP/PKG pathway in the Hippocampus of offspring

Numerous clinical and animal studies have found that antenatal chronic stress can lead to pathological changes the hippocampal development from embryos to adult, but the mechanisms are not well understood. Proteomic analyses provide a new insight to explore the potential mechanisms of this impairment. In this study, gestating rats were subjected to chronic unpredictable mild stress (CUMS) during pregnant days using nine different stimulations, and the changes of the learning and memory performance and the expression of proteins in the hippocampus of offspring were measured. It was found that prenatal chronic stress led to growth retardation, impaired spatial learning and memory ability in the offspring. Furthermore, prenatal stress caused various degrees of damage to neurons, Nissl body, mitochondria and synaptic structures in hippocampal CA3 region of offspring. In addition, 26 significantly different expressed proteins (DEPs) were found between the two groups by using isoquantitative tag-based relative and absolute quantification (iTRAQ) proteomics analysis. Further analyses of these DEPs showed that involved with different molecular functions and several biological processes, such as biological regulation and metabolic processes. Among these, the KEGG pathway enrichment showed that learning and memory impairment was mainly associated with the cyclic guanosine monophosphate protein kinase G (cGMP-PKG) pathway. At the same time, compared with OPC group, the NO, nNOS and cGMP level were significantly decreased, and the expression of PKG protein was also dropped. All of these results suggested that pregnant rats exposed to chronic psychological stress might impair spatial learning and memory ability of offspring, by disturbing the NO/cGMP/PKG signaling pathway.

Serotonin-related rodent models of early-life exposure relevant for neurodevelopmental vulnerability to psychiatric disorders

Mental disorders including depression and anxiety are continuously rising their prevalence across the globe. Early-life experience of individuals emerges as a main risk factor contributing to the developmental vulnerability to psychiatric disorders. That is, perturbing environmental conditions during neurodevelopmental stages can have detrimental effects on adult mood and emotional responses. However, the possible maladaptive neural mechanisms contributing to such psychopathological phenomenon still remain poorly understood. In this review, we explore preclinical rodent models of developmental vulnerability to psychiatric disorders, focusing on the impact of early-life environmental perturbations on behavioral aspects relevant to stress-related and psychiatric disorders. We limit our analysis to well-established models in which alterations in the serotonin (5-HT) system appear to have a crucial role in the pathophysiological mechanisms. We analyze long-term behavioral outcomes produced by early-life exposures to stress and psychotropic drugs such as the selective 5-HT reuptake inhibitor (SSRI) antidepressants or the anticonvulsant valproic acid (VPA). We perform a comparative analysis, identifying differences and commonalities in the behavioral effects produced in these models. Furthermore, this review discusses recent advances on neurodevelopmental substrates engaged in these behavioral effects, emphasizing the possible existence of maladaptive mechanisms that could be shared by the different models.

Prenatal Stress Impairs Postnatal Learning and Memory Development via Disturbance of the cGMP-PKG Pathway and Oxidative Phosphorylation in the Hippocampus of Rats

Clinical and animal studies have found that prenatal stress can lead to pathological changes in embryos and fetuses. However, the mechanisms through which this occurs have not been made clear. In the present study, pregnant rats were subjected to chronic psychological stress during gestational days using an improved communication box system, and the changes in behavioral performance and proteins in the hippocampus of offspring were analyzed. It was found that prenatal stress caused postnatal growth retardation and impairment in spatial learning and memory. Furthermore, in isobaric tags for relative and absolute quantitation-based proteomics analyses, 158 significantly differentially expressed proteins (DEPs) were found between the two groups. Further analyses showed that these DEPs are involved in different molecular function categories and participate in several biological processes, such as energy metabolism, learning or memory, and synaptic plasticity. Moreover, the enrichment of pathways showed that the learning and memory impairment was primarily connected with the cyclic guanosine monophosphate–protein kinase G (cGMP–PKG) pathway and oxidative phosphorylation. At the same time, the cGMP level and the expression of PKG protein were significantly decreased, and the neuronal mitochondria appeared to have a swollen and irregular shape in the hippocampus of offspring of stressed rats. These results suggest that the chronic psychological stress that pregnant rats were subjected to during gestational days may have impaired the spatial learning and memory of offspring. This affected the hippocampal oxidative phosphorylation and inhibited the cGMP–PKG pathway.