地塞米松预处理对缺氧缺血性脑病新生大鼠神经和体格发育的影响

目的　探讨地塞米松 (Dex)预处理对新生儿缺氧缺血性脑病 (Hypoxic- ischemicencephalopathy,HE)新生大鼠神经及体格发育的影响。方法　 4日龄 SD大鼠 85只随机分为 3组 ,分别给予生理盐水、两种剂量 Dex预处理 4天 ,然后结扎左侧颈总动脉 ,放入 37℃恒温有机玻璃缺氧房中 3h。分别于生后 1 0、1 4、2 1、2 8d取全脑标本切片作 HE染色 ,测定各组大鼠总死亡率、体重、非结扎侧皮层厚度和细胞密度。结果　 Dex组大鼠脑梗塞发生率及梗塞面积、体重、非结扎侧皮层厚度和细胞密度均少于对照组。低剂量 Dex组和高剂量 Dex组死亡率均高于对照组。两个 Dex剂量组间无明显差异。结论　 Dex预处理对 HIE新生大鼠具有神经保护作用 ,但可抑制体格生长和大脑皮层发育 ,可能导致精神运动发育迟滞

Effect of dexamethasone on development of nervous system and growth of body in neonatal rat with hypoxic-ischemic encephalopathy

Objective To investigate the effect of dexamethasone on development of nervous system and growth of body in neonatal rats with HIE.Methods 85 4 d old Sprague Dawley rat pups were randomized to 3 of 19, 32 and 34 different treatment groups.Neonatal rats were treated with either 0.1ml/kg saline or 0.1~0.5mg/kg dexamethasone for consecutive 4d.In the 7th postnatal day, after ligation of the left common carotid artery, the rats were exposed to 8% oxyen -92% nitrogen at 37℃ for 3 h.The weight was noted, and then the rats were decapitated in the 10th, 14th, 21st and 28th postnatal day.The brains were subsequently perfusion fixed and stained with hematoxylineosin.In the non ligated side motor cortex, the area of infarction, the density and thickness of cells was measured with a microcomputer image analysis system(MCID),respectively.Results The rate of ligated side brain damage was lower in both Dex groups.However, a high mortality rate (71.43%) was noted in the high dose Dex groups.The weight of rats in both Dex groups was lower than that of the saline group.The density and the thickness of cells in cortical was lower in both Dex groups than that of the saline group in the 14th and 21st postnatal days (P<0.005 each).But that was still lower in higher dose Dex group in the 28th postnatal day(P<0.001).Conclusion Pretreatment with Dex suppresses neuronal maturation of the brain and physical growing in neonatal rat, it may give rise to psychomotor retardation later.