| Summary: | 碩士 === 國立臺灣大學 === 生理學研究所 === 102 === This thesis was to examine whether a maternal n-3 fatty acid-deficient diet during pregnancy and lactation altered the hypothalamic-pituitary-adrenal (HPA) axis responses and negative feedback regulation leading to anxiety and depression behaviors in postpartum rats and in the offspring later in life. Docosahexaenoic acid (DHA, 22:6n-3), is specifically enriched in the brain and is essential for normal neurological function. Most DHA accumulation in the brain occurs during brain development and is supplied via the placenta to the fetus and in the breast-fed milk to the pup. Pregnant rats were fed a sunflower oil-based n-3 fatty acid-deficient diet or the same diet supplemented with fish oil as an n-3 fatty acid-adequate diet during pregnancy and lactation. The maternal rats were maintained on the same diet till sacrificed at postpartum day 30. The pups, after weaning at postnatal day 22, were fed chow diet till sacrificed at 10-week-old. We found that the maternal rats fed an n-3 fatty acid-deficient diet showed significant lower licking/grooming and arch-back nursing behavior, increased in sensitivity to dexamethasone suppression following restraint stress-induced serum corticosterone levels, and enhanced depressive-like behavior in the forced-swimming test and anxiety-like behavior in the plus-maze test compared to the maternal rats fed an n-3 fatty acid-adequate diet. Exposure to the maternal n-3 fatty acid-deficient diet during the brain development was resulted, at newborn and weaning, in a significant reduced offspring body weight. DHA deficiency during the brain development significantly increased and prolonged restraint stress-induced changes in colonic body temperature and serum corticosterone levels, caused a significant increase in sensitivity to dexamethasone suppression with corticotrophin releasing hormone- or restraint stress-induced serum corticosterone
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changes, and enhanced depressive-like behavior in the forced-swimming test and anxiety-like behavior in the plus-maze test in later life. In addition, DHA deficiency during the brain development in female offspring significantly increased in sensitivity to dexamethasone suppression with restraint stress-induced serum corticosterone changes than the male offspring. However, the male offspring compared to females, showed higher depressive-like behavior in the forced-swimming test and anxiety-like behavior in the plus-maze test. These results suggest that a maternal n-3 fatty acid-deficient diet during pregnancy and lactation leads to excessive HPA responses and dysregulation to stress and elevated behavioral indices of depression and anxiety in postpartum rats and the offspring later in life.
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