Effects of Chronic Psychosocial Stress on Reduction of Basal Glucocorticoid Levels and Suppression of Glucocorticoid Levels Following Dexamethasone Administration in Animal Model of PTSD

Aim: To further examine the neurobiological mechanisms and their outcomes responsible for the PTSD sequelae induced by laboratory animal model and to explore the effects of chronic psychosocial paradigm. We tested the hypothesis that our animal model of PTSD would display abnormalities in glucocorticoid levels that are manifest in people with PTSD and that psychosocially stressed rats exhibit a significantly greater suppression of corticosterone levels than control rats following the administration of dexamethasone.Methods: Animals were divided into two groups. The experimental group was scheduled to exposure to two types of stressors: double exposure to acute immobilization stress, and combined predator-threat stress and daily social stress. There was also administration of dexamethasone in combination with stress exposure.Results: There was a statistical difference between masses of thymus in the stress group and stress group with dexamethasone appliance (p=0.024). We found statistical significance between baseline cortisol and stress induced levels of cortisol and between stress induced group and return to baseline group.Conclusion: Significant changes in HPA activity, reductions in basal glucocorticoid levels and enhanced dexamethasone induced inhibition of glucocorticoid levels have been manifested. All of this is manifested in PTSD patients also as many other stress induces changes

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

IntroductionThere 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.MethodsTo 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.ResultsResults 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.DiscussionThis 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

Glucocorticoid levels after exposure to predator odor and chronic psychosocial stress with dexamethasone application in rats

AbstractThis study was conducted to explore the effects of specific psychosocial paradigm on predator animal posttraumatic stress model and to test the hypothesis that psychosocially stressed rats would exibit abnormal levels of cortisol and a larger suppression of cortisol levels after the application of dexamethasone. Animals were divided in two groups: experimental and control groups. The experimental group was exposed to two types of stressors: acute immobilization stress, and combined predator stress and daily social stress with application of dexamethasone. Blood sampling was performed at three different times. We found statistically significant results after analyzing the differences between cortisol levels in different times of blood sampling in the group of animals exposed to stress with dexamethasone application. Statistical significance was found when we compared the experimental group with the control group in terms of elevated cortisol levels during blood sampling after stress paradigm exposition. Many significant disruptions in the functioning of the hypothalamic–pituitary–adrenal axis were observed, such as decrease in basal cortisol levels and enhanced dexamethasone-induced inhibition of cortisol levels. These findings are important because their impact can translate to human individuals with posttraumatic stress disorder, which is the most important role of every animal model in research

Morphometric and volumetric analysis of lacrimal glands in patients with thyroid eye disease

Abstract Assessment of morphometric and volumetric changes in lacrimal glands in thyroid eye disease, its clinical manifestations in relation of disease progression. Retrospective volumetric analysis included both genders and was performed on total of 183 patients - 91 patients with diagnosed Grave’s disease and thyroid eye disease and 92 patients without Grave’s disease and thyroid eye disease who underwent multidetector computed tomography (MDCT) examination in routine daily work according to other medical indications. In the group of females, there was statistical significance between patients with thyroid eye disease and controls who were smoking and had body weight gain. We found statistical significance in volumetric enlargements for both orbits in both genders for the patients group when compared to controls. There was also statistical significance in morphometric characteristics for the lacrimal gland diameters measured. Determination planimetric morphometric parameters of importance were coronary height of lacrimal gland of the right eye, coronary height of lacrimal gland of the left eye and coronary width of lacrimal gland of the left eye for the group of males. In a group of females the established determination parameters of importance were the coronary height of lacrimal gland of the left eye, the axial width of lacrimal gland of the left eye, volume of lacrimal gland of the right eye and the volume of lacrimal gland of the left eye. When we compared the displaced lacrimal gland coming forward (proptosis) in time progressing disease between group of patients and controls, we also found statistical significant connection. Evaluation of lacrimal gland volumetric and morphometric data may increase validity of defining this anatomical substrate and its morphology disruption as liable tool for thyroid eye disease progression follow up and treatment planning and outcome