اثر متفاوت استرس خفیف و شدید در اوایل زندگی بر پاسخ رفتاری به شکست اجتماعی در موشهای بزرگ آزمایشگاهی بالغ و مورفولوژی نورونهای هرمی CA3.

Introduction: We studied the effects of two types of early life stress (ELS) on the later response to social defeat stress and vulnerability to stress-induced emotional disorders. The structural alterations of the CA3 pyramidal were also evaluated. Methods and Materials: For early handling (EH) or maternal deprivation (MD), newborn rats were isolated from their mothers for 15min/d or 3h/day on postnatal day (PND) 1-21, respectively. Social defeat (SD) stress consisted of physical and sensory confrontation with an aggressive adult male rat on PND 56-59. On PND 61-65, animals from different groups were subjected to open-field test, elevated plus-maze and forced swim test, and then their brains were dissected out and processed for Golgi-cox staining. Results: Social defeat stress in adult rats led to increased anxiety and depressive-like behaviors, as expected. This was accompanied by reductions in dendritic spines and the size of CA3 hippocampal neurons. Early handling ameliorated both behavioral and structural alterations caused by social defeat stress. On the other hand, rats that experienced maternal deprivation (MD-SD) displayed intensified behavioral and structural changes compared to socially defeated rats alone. The MD-SD rats also exhibited significant retraction of apical dendrites and pronounced reduction in dendritic spine density. Conclusion: These findings suggest that different types of ELS can impact the risk for affective disorders in response to social stress in adulthood. The changes in dendritic structure and spine density in CA3 neurons highlight potential mechanisms underlying the effects of early life stress on the behavioral response to stress in adulthood. [ABSTRACT FROM AUTHOR]