摘要
目的观察大剂量糖皮质激素(GC)对下丘脑室旁核(PVN)神经元促肾上腺皮质激素释放激素(CRH)蛋白表达、CRHmRNA转录的调节作用,以了解大剂量GC与生理剂量的GC经典作用是否存有差异。方法Wistar大鼠60只,随机分为10-6mol/L DEX组、10-9mol/L地塞米松(DEX)组、等渗盐水组以及预先予以10-4mol/LRU486,再予以10-6mol/LDEX组(以上均为终浓度),通过预先股静脉置管给入。利用免疫组织化学与激光共聚焦扫描技术,观察CRH蛋白表达的情况;利用原位杂交技术,观察PVN神经元CRH mRNA转录的变化。结果终浓度10-6mol/L DEX作用约20min后,PVN神经元胞浆内出现CRH mRNA阳性染色颗粒;作用约30min后,出现CRH蛋白阳性荧光颗粒。预先拮抗糖皮质激素受体(GR)后,上述10-6mol/L DEX的促进作用被逆转。10-9mol/L DEX、等渗盐水与空白对照均无类似表现。结论大剂量GC可使PVN神经元CRH基因表达上调,这与经典GC的作用具有较大差异,可能由于大剂量GC依赖于mGR而经典GC的作用主要经由iGR所致。
Objective To observe the regulative effect of high dose of glucocorticoid （GC） on protein synthesis and mRNA transcription of corticotropin - releasing hormone （ CRH ） in paraventricular hypothalamic nucleus （PVN） so to ascertain whether there exists difference upon effect of GC either at high dose or at normal dose. Methods A total of 60 Wistar rats were divided into five groups, ie, blank control group, 10^-6 mol/L dexamethasone （DEX） group, 10^-9 mol/L DEX group, 9 g/L saline group and group that was treated with 10^-4mol/L RU486 first and then with 10^-6 mol/L DEX. The drugs were given through femoral vein. CRH protein expression was measured by means of immunohistochemistry and laser confocal scanning microscophy （LCSM） ; CRH mRNA transcription level was investigated by in situ hybridization. Results There appeared positive CRH mRNA granules in cytoplasm of PVN after administration with 10^-6 mol/L DEX for 20 minutes but could be seen positive fluorescent granules of CRH protein 30 minutes later, which was reversed at an in advance blockage of GR, as was free in 10^-9 mol/L DEX group, 9 g/L saline group and blank control group. Conclusions High dose of GC can up regulate CRH gene expression in PVN and differs much from the traditional effect of GC at normal dose, as may be due to that high dose of GC exerts effects depending on membrane glucocorticoid receptor but normal dose of GC dose via iGR.
出处
《中华创伤杂志》
CAS
CSCD
北大核心
2005年第10期737-740,共4页
Chinese Journal of Trauma
基金
国家重点基础研究发展规划基金资助项目(G1999054201)
