【作者】 王团美；

【导师】 薄涛；

【作者基本信息】 中南大学 ， 儿科学， 2008， 硕士

【摘要】 目的现今普遍认为除兴奋毒性机制氧自由基损伤外炎症在发育中脑损伤病理生理过程中占有重要地位。糖皮质激素(glucocorticoid,GC)作为强有力的抗炎物质,能有效地抑制致炎症信号和相关基因表达,但在脑发育期不恰当应用GC可能严重影响脑发育。在脑内,GC是通过糖皮质激素受体(glucocorticoidreceptor,GR)发挥作用。本实验通过研究新生期大鼠反复惊厥对皮质区GR表达的影响,探讨脑内GR和发育期脑损伤变化之间关系。方法48只生后7天(postnatal day 7,PN-7d)的SD大鼠随机分成惊厥组和对照组,每组24只,惊厥组每日吸入三氟乙醚诱导惊厥发作1次,每次持续30 min,连续6d;对照组同样操作但不吸入三氟乙醚。两组大鼠于反复惊厥后(after recurrent seizures,ARS)1d、3d、7d随机各选取8只大鼠断头去脑,分别采用Western blots及免疫组织化学方法观察大鼠大脑皮层GR表达的变化。结果(1)通过Western blots发现在大脑皮质区GR生后即有表达,随着日龄的增加大脑皮层GR的表达呈现一定的规律性。在生后早期新生大鼠GR主要表达于胞浆,而后胞核中表达迅速增加。与正常对照组相比较,惊厥组大鼠ARS—1d(PN—13d)及ARS-7 d(PN—19d)时,胞浆蛋白中GR表达无显著性差异(P＞0.05);ARS—3d(PN—15d)惊厥组大鼠皮层胞浆蛋白中GR表达显著降低(P＜0.05)。与正常对照组相比较,惊厥组大鼠ARS—1d(PN—13d)及ARS-3d(PN-15d)时皮层胞核蛋白中均未检出GR的表达,ARS-7 d(PN-19d)时惊厥大鼠皮层胞核蛋白中GR表达显著降低(P＜0.05)。(2)通过免疫组织化学方法发现GR在皮质表达丰富,随着日龄的增加大脑皮层各叶GR的表达呈现一定时相性和区域性。在PN—13d时,GR阳性部位为胞浆,在PN—15d、PN—19d时胞核区也出现阳性表达。在ARS-1d(PN—13d)时,惊厥组大鼠顶叶区GR免疫化学累计光密度(accumulate optical density,AOD)明显低于正常对照组(P＜0.05),而在额叶、颞叶区两组无显著性差异(P＞0.05):在ARS-3d(PN—15d)时,惊厥组大鼠皮层顶叶、颞叶区GR免疫化学AOD明显低于正常对照组(P＜0.05),在额叶区无显著性差异(P＞0.05);在ARS-7d(PN—19d)时,惊厥组大鼠皮层顶叶、颞叶和额叶区GR免疫化学AOD明显低于正常对照组(P＜0.05)。结论(1)皮质区GR随脑发育成熟表达呈现一定规律性及分布特点,与脑发育过程密切相关。(2)新生大鼠反复惊厥造成大脑皮层GR表达的异常,可能参与反复惊厥所致发育期脑急性损伤。更多还原

【Abstract】 Objective:To investigate the short-term effects of flurothyl-induced neonatal recurrent seizures on glucocorticoid receptor(GR)expressions in rat brain.Methods:48 of postnatal(PN-)7d Sprague-Dawley rats were divided randomly into two groups:the control group and the seizure group.Seizures were induced by inhalant flurothyl daily in six consecutive days.The brains of rats were sampled on after-recurrent-seizure(ARS)- ld(PN-13d),ARS-3d(PN-15d)and ARS-7d(PN-19d).The expressions of GR protein in cerebral cortex were detected by immunohistochemistry and Western blots methods.Results:The expression of GR in the cerebral cortex of rat pup has been found by western blot and immunohistochemistry method since PN-13d.The expression of GR was found in the cellular plasma on PN-13d,and that was found in the cellular nucleus and plasma on PN-15d and PN-19d.By western blot method,we found that the expressions of GR in the cellular plasma of cerebral_Ⅱcortex were similar in between two group on ARS-1d(PN-13d)and ARS-7d(PN-19d)(P＞0.05),but the expressions of GR in the cellular plasma of cerebral cortex decreased significantly in seizure rats than those in control rats on PRS-3d(PN-15d) (P＜0.05);the GR proteins were hardly expressed in the nucleus of seizure rat cortex on ARS-1d and ARS-3d,and the expressions of GR in the cellular nucleus of cerebral cortex decreased significantly in seizure rats than those in control rats on ARS-7d(PN-19d)(P＜0.05).On ARS-1d (PN-13d),the immunochemical accumulate optical densify(AOD)of GR protein in the parietal cortex decreased significantly in seizure rats than those in the control rats(P＜0.05),but the immunochemical AODs of GR protein were similar between two groups in the temporal cortex and frontal cortex(P＞0.05).On ARS-3d(PN-15d),the immunochemical AOD of GR protein in the parietal cortex and temporal cortex decreased significantly in seizure rats than those in control rats(P＜0.05),but the immunochemical AODs of GR protein were similar between two groups in the frontal cortex(P＞0.05).On ARS-7d(PN-19d),the immunochemical AODs of GR protein in the parietal cortex,temporal cortex,and frontal cortex were decreased significantly in seizure rats than those in control rats(P＜0.05).Conclusions:Recurrent seizures in neonatal rats modify GR expression in the developmental rat brain.This phenomenon raised the possibility that abnormal GR expression might play an important role in developmental brain injury.更多还原