The Single Prolonged Stress protocol is considered a model for PTSD, as it induces long lasting changes in rat behaviour and endocrine regulation. Previous work demonstrated that some of these... Show moreThe Single Prolonged Stress protocol is considered a model for PTSD, as it induces long lasting changes in rat behaviour and endocrine regulation. Previous work demonstrated that some of these changes can be prevented by treatment with the glucocorticoid receptor antagonist RU486, administered a week after the stressor. The current study evaluated the effects of an earlier intervention with RU486, as evaluated 1 week after SPS-exposure. Most RU486 effects occurred independent of prior stress, except for the reversal of a stress-induced increase in locomotor behaviour. The accompanying changes in gene expression depended on gene, brain region, and time. DNA methylation of the robustly down-regulated Fkbp5 gene was dissociated of changes in mRNA expression. The findings reinforce the long term effects of GR antagonist treatment, but also emphasize the need to evaluate changes over time to allow the identification of robust correlates between gene expression and behavioural/endocrine outcome of stressful experiences. Show less
Ding, J.L.; Silva, M.S. da; Lingeman, J.; Chen, X.Z.; Shi, Y.X.; Han, F.; Meijer, O.C. 2019
Background: Stressors activate a wide spectrum of interacting hormonal and neuronal systems resulting in behavioral and physiological responses, with consequences for the development of... Show moreBackground: Stressors activate a wide spectrum of interacting hormonal and neuronal systems resulting in behavioral and physiological responses, with consequences for the development of psychopathology. Several recent studies demonstrated that treatment with the glucocorticoid receptor (GR) antagonist RU486 during adulthood normalized effects of early life stress. We aimed to evaluate the potential of RU486 to reverse stress-induced changes in an animal model of adult stress.Method: We employed the single-prolonged stress (SPS) model as a multimodal stress exposure protocol in male rats. SPS rats and unstressed controls were treated with RU486 on days 8, 9, 10 after stress exposure and the effects of treatment were evaluated after another 4 days. We determined body weight gain, corticosterone levels, behavioral reactivity in anxiety tests, and brain gene expression of c-fos, corticosteroid receptors, drivers of the stress response and genes (epi-)genitally linked to PTSD.Results: RU486 affected body weight gain, corticosterone levels and open field behavior only in SPS rats. RU486 had history-independent effects in reducing fear in the elevated plus maze and fear conditioning behavior. Gene expression analysis showed a diversity of in- and interdependent effects of stress and RU486.Conclusion: The effects of RU486 applied 1 week after stress and measured 4 days after treatment demonstrate that in the state of post-SPS the GR-dependence of homeostatic processes has changed. This suggests that GR-mediated processes are part of allostatic regulation after adult stress. The normalization of a number of SPS-effects after RU486 treatment reinforces the potential of targeting GR for treatment of stress-related psychopathologies. Show less
