| Glucocorticoids are essential for fetus normal development. Since Liggins reported that prenatal GCs therapy at risk of preterm delivery could reduce morbidity of NRDS, GCs had used for more than thirty years in obstetrics. Recently more and more people begin to use repeated courses of prenatal GCs therapy. There is growing evidence that exposure of the fetal brain to excess GCs, at critical stages of development,can have life-long effects. The purpose of this study was to investigate the effects of antenatal GC on qutanity, morphons of neuron and Synaptophysin expression; the alteration of the ability of spatial learning; the mechanisms of the signal transduction procedure mediated by glucocorticoid receptor and mineralocorticoid receptor in a rat model of antenatal GC therapy.Materials and MethodsHealth female SD rats of three-month-old, forty five in all, were mated in estrus. It could produces accurately time-dated pregnant rats by the method of vaginal smear. Pregnant rats on day 18 (E18) were divided randomly into three groups: repeated courses group, pregnant rats were given intramuscular dexamethasone (0.48mg/Kg·dose) after 18 day's gestation, q·4h, a course contains four doses, only one course a day, for three days; single couse group, pregnant rats were given intramuscular dexamethasone for one course on E18, the other two days received... |
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