Adrenal response of male rats exposed to prenatal stress and early postnatal stimulation

Abstract

Stress in pregnant rats caused by chronic immobilization alters the pattern of secretion of corticosterone and modifies the hypothalamic-pituitary-adrenal axis (HPA) of the fetus. Early postnatal handling, however, may reverse the effects of increased secretion of corticosterone. We investigated the effects of prenatal stress and postnatal handling on the activity of the HPA axis of male offspring of stressed female rats. Male 90-day-old rats from four groups were investigated: prenatally stressed animals without postnatal handling, prenatally stressed animals with postnatal handling, unstressed control animals with postnatal handling, and unstressed control animals without postnatal handling. After sacrifice, the adrenal glands were weighed to determine the adrenal-somatic index. Apoptosis was evaluated by TUNEL assay and active caspase-3 expression. We found that the adrenal gland cortex:medulla ratio increased in animals with prenatal stress and that eventually the stress caused apoptosis. Handling newborns to simulate maternal activity ameliorated some of the negative effects of prenatal stress.

Voluntary physical exercise protects against behavioral and endocrine reactivity to social and environmental stressors in the prairie vole

“…The current findings are consistent with those of Campeau et al (2010), in which exercise animals displayed blunted ACTH and corticosterone responses to an acute novel environment compared to sedentary animals. Prairie voles in the exercise group also had a significantly smaller adrenal weight to body weight ratio, compared to the sedentary condition, suggesting that exercise can protect against enlarged adrenal glands, which has been observed previously in chronically stressed animals (Kim et al, 2008; Liaudat et al, 2015). Taken together, the current findings indicate that voluntary physical activity attenuates both acute and chronic endocrine stress responses.…”

Modulation of the Hypothalamic-Pituitary-Adrenal Axis by Early Life Stress Exposure

“…These ELS-induced alterations in corticosterone plasma levels could obviously be caused by the earlier mentioned alterations in CRH and ACTH release, but could also be attributed to abnormal function of the adrenal gland itself, as increases in adrenal weight and cortex-to-medulla ratio have been reported as a consequence of PS (Ward et al, 2000; Fan et al, 2009; Liaudat et al, 2015). However, the frequent inconsistencies in findings emphasize the extremely complex modulatory effects ELS exerts on the HPA-axis, depending on the precise developmental stage affected, the exact stressor used (its frequency, duration, etc.…”

“…To study the effects of prenatal stress (PS) exposure on the offspring, dams are most frequently stressed by physical restraint (Lemaire et al, 2000; Mandyam et al, 2008; Belnoue et al, 2013; de Souza et al, 2013; Madhyastha et al, 2013; Xu et al, 2014) or immobilization of the limbs (Liaudat et al, 2015), often for multiple times a day. Alternatively, exposure to foot shocks (Estanislau and Morato, 2005, 2006), hypoxia (Fan et al, 2009; Wang X. et al, 2013), or multiple variable stressors over the course of multiple days (Lee et al, 2007; Fan et al, 2009; Zohar and Weinstock, 2011) are applied.…”

Attenuation effects of prenatal stress by early postnatal stimulation in different research models

“…59 Another possible mechanism involved in the disruption of corticosterone levels observed in prenatally stressed rats was the altered parameters of adrenal gland physiology. As Liaudat et al 61 showed, the cortex:medulla ratio, apoptotic index and caspase 3 expression of adrenal gland returned to control levels when the prenatally stress animals were handled. Figure 1 shows the timeline of experimental events in a research model aimed to evaluate the effects of prenatal stress and PS on endocrine and immune systems.…”