The long-term effects of maternal deprivation on the number and size of inhibitory interneurons in the rat amygdala and nucleus accumbens.

Introduction: There is an increasing evidence supporting the hypothesis that traumatic experiences during early developmental periods might be associated with psychopathology later in life. Maternal deprivation (MD) in rodents has been proposed as an animal model for certain aspects of neuropsychiatric disorders. Methods: To determine whether early-life stress leads to changes in GABAergic, inhibitory interneurons in the limbic system structures, specifically the amygdala and nucleus accumbens, 9-day-old Wistar rats were exposed to a 24 h MD. On postnatal day 60 (P60), the rats were sacrificed for morphometric analysis and their brains were compared to the control group. Results: Results show that MD affect GABAergic interneurons, leading to the decrease in density and size of the calcium-binding proteins parvalbumin-, calbindin-, and calretinin-expressing interneurons in the amygdala and nucleus accumbens. Discussion: This study indicates that early stress in life leads to changes in the number and morphology of the GABAergic, inhibitory interneurons in the amygdala and nucleus accumbens, most probably due to the loss of neurons during postnatal development and it further contributes to understanding the effects of maternal deprivation on brain development.

The impact of early life maternal deprivation on the perineuronal nets in the prefrontal cortex and hippocampus of young adult rats.

Early life stress negatively impacts brain development and affects structure and function of parvalbumin immunopositive (PV+) inhibitory neurons. Main regulators of PV+ interneurons activity and plasticity are perineuronal nets (PNNs), an extracellular matrix formation that enwraps PV+ interneurons mainly in the neocortex and hippocampus. To experimentally address the impact of early life stress on the PNNs and PV+ interneurons in the medial prefrontal cortex and dorsal hippocampus in rats, we employed a 24 h maternal deprivation protocol. We show that maternal deprivation in the medial prefrontal cortex of adult rats caused a decrease in density of overall PNNs and PNNs that enwrap PV+ interneurons in the rostral cingulate cortex. Furthermore, a staining intensity decrease of overall PNNs and PNN+/PV+ cells was found in the prelimbic cortex. Finally, a decrease in both intensity and density of overall PNNs and PNNs surrounding PV+ cells was observed in the infralimbic cortex, together with increase in the intensity of VGAT inhibitory puncta. Surprisingly, maternal deprivation did not cause any changes in the density of PV+ interneurons in the mPFC, neither had it affected PNNs and PV+ interneurons in the hippocampus. Taken together, our findings indicate that PNNs, specifically the ones enwrapping PV+ interneurons in the medial prefrontal cortex, are affected by early life stress.

Effects of Maternal Deprivation on the Prefrontal Cortex of Male Rats: Cellular, Neurochemical, and Behavioral Outcomes.

Stressful events experienced during early life are associated with increased vulnerability of developing psychopathology in adulthood. In the present study, we exposed 9-day-old Wistar rats to 24 h maternal deprivation (MD) with the aim to investigate the impact of early life stress (ELS) on morphological, biochemical, and functional aspects of the prefrontal cortex (PFC), a brain region particularly sensitive to stress. We found that in the superficial medial orbital cortex (MO), young adult male rats had reduced density of GAD67 and CCK immunopositive cells, while the rostral part of the ventral lateral orbital cortex (roVLO) showed a decrease in the density of GAD67 immunopositive cells in both superficial and deep layers. In addition, the superficial rostral part of area 1 of the cingulate cortex (roCg1) and deep prelimbic cortex (PrL) was also affected by MD indicated by the reduction in PV immunopositive cellular density. Furthermore, MD induced upregulation of brain-derived neurotrophic factor (BDNF), while it did not affect the overall expression of Iba1 in neonatal or young adult PFC as measured by Western blot, however, microglial activation in young adult MD rats was detected immunohistochemically in deep layers of MO and infralimbic cortex (IL). Interestingly, when young adult male rats were subjected to a behavioral flexibility test in a T-maze, MD rats showed a subtle impairment in T-maze reversal learning indicating a mildly affected PFC function. Taken together, our findings demonstrated that MD reduced the density of interneurons and induced microglial activation, in particular, PFC areas at young adulthood, and could alter synaptic plasticity accompanied by PFC dysfunction.

Maternal Deprivation in Rats Decreases the Expression of Interneuron Markers in the Neocortex and Hippocampus.

Early life stress has profound effects on the development of the central nervous system. We exposed 9-day-old rat pups to a 24 h maternal deprivation (MD) and sacrificed them as young adults (60-day-old), with the aim to study the effects of early stress on forebrain circuitry. We estimated numbers of various immunohistochemically defined interneuron subpopulations in several neocortical regions and in the hippocampus. MD rats showed reduced numbers of parvalbumin-expressing interneurons in the CA1 region of the hippocampus and in the prefrontal cortex, compared with controls. Numbers of reelin-expressing and calretinin-expressing interneurons were also reduced in the CA1 and CA3 hippocampal areas, but unaltered in the neocortex of MD rats. The number of calbinin-expressing interneurons in the neocortex was similar in the MD rats compared with controls. We analyzed cell death in 15-day-old rats after MD and found no difference compared to control rats. Thus, our results more likely reflect the downregulation of markers than the actual loss of interneurons. To investigate synaptic activity in the hippocampus we immunostained for glutamatergic and inhibitory vesicular transporters. The number of inhibitory synapses was decreased in the CA1 and CA3 regions of the hippocampus in MD rats, with the normal number of excitatory synapses. Our results indicate complex, cell type-specific, and region-specific alterations in the inhibitory circuitry induced by maternal deprivation. Such alterations may underlie symptoms of MD at the behavioral level and possibly contribute to mechanisms by which early life stress causes neuropsychiatric disorders, such as schizophrenia.

Long-Term Effects of Maternal Deprivation on Redox Regulation in Rat Brain: Involvement of NADPH Oxidase.

Maternal deprivation (MD) causes perinatal stress, with subsequent behavioral changes which resemble the symptoms of schizophrenia. The NADPH oxidase is one of the major generators of reactive oxygen species, known to play a role in stress response in different tissues. The aim of this study was to elucidate the long-term effects of MD on the expression of NADPH oxidase subunits (gp91phox, p22phox, p67phox, p47phox, and p40phox). Activities of cytochrome C oxidase and respiratory chain Complex I, as well as the oxidative stress parameters using appropriate spectrophotometric techniques were analyzed. Nine-day-old Wistar rats were exposed to a 24 h maternal deprivation and sacrificed at young adult age. The structures affected by perinatal stress, cortex, hippocampus, thalamus, and caudate nuclei were investigated. The most prominent findings were increased expressions of gp91phox in the cortex and hippocampus, increased expression of p22phox and p40phox, and decreased expression of gp91phox, p22phox, and p47phox in the caudate nuclei. Complex I activity was increased in all structures except cortex. Content of reduced glutathione was decreased in all sections while region-specific changes of other oxidative stress parameters were found. Our results indicate the presence of long-term redox alterations in MD rats.

Long-term Effects of Maternal Deprivation on the Volume, Number and Size of Neurons in the Amygdala and Nucleus Accumbens of Rats.

BACKGROUND: Maternal deprivation (MD) in rodents is an important neurodevelopmental model for studying a variety of behavioral changes which closely resemble the symptoms of schizophrenia in humans. SUBJECTS AND METHODS: To determine whether early-life stress leads to changes in the limbic system structures: the amygdala and the nucleus accumbens, 9-day-old Wistar rats were exposed to 24 hour MD. On P60 the rats were sacrificed for morphometric analysis and their brains were compared to the control group. RESULTS: Results show that MD affected important limbic system structures: the amygdala and the nucleus accumbens, whose volume was decreased (17% of the control value for the amygdala and 9% of the control value for the nucleus accumbens ), as well as the number of neurons (41% of the control value for the amygdala and 43% of the control value for the nucleus accumbens ) and the size of their cells soma (12% of the control value for the amygdala and 33% of the control value for the nucleus accumbens ). CONCLUSION: This study indicates that early stress in life leads to changes in the morphology of the limbic areas of the brain, most probably due to the loss of neurons during postnatal development, and it further contributes to our understanding of the effects of maternal deprivation on brain development.

Brain changes in patients with posttraumatic stress disorder and associated alcoholism: MRI based study.

BACKGROUND: Studies imposing rigorous control over lifetime alcohol intake usually have not found smaller hippocampal volumes in persons with posttraumatic stress disorder (PTSD). Since the majority of negative studies have used adolescent samples, it has been suggested that chronicity is a necessary condition for such findings. We have hypothesized that the volumes of hippocampus, amygdale, prefrontal cortex and the intracranial volume are reduced in the patients with PTSD and excessive alcohol intake. SUBJECTS AND METHODS: Study has been carried out on 54 therapy naive PTSD suffering subjects and healthy controls, divided in two groups: 29 with PTSD and consequent alcoholism, 25 with PTSD but without problems of excessive alcohol intake, and 25 healthy volunteers. All of the patients underwent same magnetic resonance imaging (MRI) protocol and volumetric evaluation of the region of interest. RESULTS: Only hippocampal volume appeared to be significantly reduced in patients with PTSD and alcoholism. Other differences in the volumes obtained remained to be insignificant. CONCLUSION: Alcohol intake definitely worsens the deterioration of the hippocampal formation in PTSD suffering patients. Nevertheless, other structures of interest for this study did not manifest any kind of statistical differences in volumetric analysis.

The influence of sex hormones on anterior cruciate ligament ruptures in males.

PURPOSE: The purpose of this study is to determine the difference in the concentrations of testosterone, 17-ß estradiol and progesterone between male patients with and without ACL rupture, as well as the possible effect of these hormones on generalized joint laxity. METHODS: Male subjects with non-contact knee joint injury were included in this study. Two groups were formed: the examined group, consisting of subjects with ACL rupture and the control group consisting of patients without ACL rupture. After this, the patients from these two groups were paired off on the basis of three factors, level of professional involvement in sports (including the type of sports activity), left or right side of the body and the age of the subjects. In the end, there were 29 pairs (58 subjects). The concentration of sex hormones was determined from saliva specimens with the aid of the Salimetrics enzyme immunoassay. The testing of generalized joint laxity was performed with the aid of the "laxity score" according to Beighton et al. RESULTS: Subjects with ACL rupture have highly statistically significantly greater concentrations of testosterone (p < 0.01), statistically significantly greater concentrations of 17-ß estradiol (p < 0.05), and a highly statistically significantly greater generalized joint laxity score than subjects with an intact ACL (p < 0.01). CONCLUSION: Increased concentrations of testosterone or 17-ß estradiol may be a risk factor leading to ACL rupture. Also, generalized joint laxity may be a factor leading to ACL rupture, but none of the monitored hormones can be set down as the cause of its existence. Young male athletes with higher concentrations of testosterone and greater hyperelasticity should plan preventive programs of physiotherapy for ACL preservation since they present a vulnerable group susceptible to ACL rupture. LEVEL OF EVIDENCE: Diagnostic study, Level II.

Long-term effects of maternal deprivation on the neuronal soma area in the rat neocortex.

Early separation of rat pups from their mothers (separatio a matrem) is considered and accepted as an animal model of perinatal stress. Adult rats, separated early postnatally from their mothers, are developing long-lasting changes in the brain and neuroendocrine system, corresponding to the findings observed in schizophrenia and affective disorders. With the aim to investigate the morphological changes in this animal model we exposed 9-day-old (P9) Wistar rats to a 24 h maternal deprivation (MD). At young adult age rats were sacrificed for morphometric analysis and their brains were compared with the control group bred under the same conditions, but without MD. Rats exposed to MD had a 28% smaller cell soma area in the prefrontal cortex (PFCX), 30% in retrosplenial cortex (RSCX), and 15% in motor cortex (MCX) compared to the controls. No difference was observed in the expression of glial fibrillary acidic protein in the neocortex of MD rats compared to the control group. The results of this study demonstrate that stress in early life has a long-term effect on neuronal soma size in cingulate and retrosplenial cortex and is potentially interesting as these structures play an important role in cognition.

Thermomineral water promotes axonal sprouting but does not reduce glial scar formation in a mouse model of spinal cord injury.

Thermomineral water from the Atomic Spa Gornja Trepca has been used for a century in the treatment of neurologic disease. The thermomineral water contains microelements, including lithium and magnesium, which show neural regeneration-promoting effects after central nervous system injury. In this study, we investigated the effects of oral intake of thermomineral water from the Atomic Spa Gornja Trepca on nerve regeneration in a 3-month-old mouse model of spinal cord injury. The mice receiving oral intake of thermomineral water showed better locomotor recovery than those without administration of thermomineral water at 8 and 12 weeks after lower thoracic spinal cord compression. At 12 weeks after injury, sprouting of catecholaminergic axons was better in mice that drank thermomineral water than in those without administration of thermomineral water, but there was no difference in glial reaction to injury between mice with and without administration of thermomineral water. These findings suggest that thermomineral water can promote the nerve regeneration but cannot reduce glial scar formation in a mouse model of spinal cord injury.

Long-term effects of the maternal deprivation on the volume and number of neurons in the rat neocortex and hippocampus.

Maternal deprivation (MD) leads to a variety of behavioral changes in rats which closely resemble the symptoms of schizophrenia in humans. With the aim to investigate the morphological changes which underlie the behavioral insults in this experimental paradigm we exposed 9-day-old Wistar rats to a 24 h MD. At the period of young adulthood rats were sacrificed for morphometric analysis and their brains were compared to the control group. Rats exposed to MD had a decrease in hippocampal volume (71 percent of the control value) as well as a decrease in the size of pyramidal (62 percent of the control) and granular (60 percent of the control) cell layers. Also, there was a decrease in the thickness of the prefrontal, retrosplenial and motor cortex compared to the control group. Analysis of the density of NeuN-immunolabeled neurons revealed a reduction in retrosplenial and prefrontal cortex (70 percent and 81 percent of the control, respectively), while there was no difference in the motor cortex. Western blot analysis confirmed a decrease in NeuN expression in the MD group compared to the control rat brain homogenates. The results of this study show that early stress in life has a long-term effect on the morphology of cognitive brain regions, most probably due to the loss of neurons during postnatal development and further contributes to our understanding of the effects of maternal separation on brain development.