一氧化碳对热性惊厥大鼠γ-氨基丁酸B受体亚基的调节作用

Influence of heme oxygenase/carbon monoxide system on γ-aminobutyric acid B-receptor subunits in hippocampus of rats with febrile seizures

摘要:

目的：气体信号分子一氧化碳(CO)与γ-氨基丁酸B受体(GABABR)亚基均参与了热性惊厥(FS)发病机制。该研究旨在探讨CO对FS大鼠GABABR亚基表达的影响。方法：32只大鼠随机分为对照组(37.0℃水浴),FS组(45.2℃水浴),FS+锌原卟啉Ⅸ组(45.2℃水浴),FS+血晶素组(45.2℃水浴),每组8只。采用热水浴诱导大鼠FS,隔日诱导1次,共10次。采用双波长分光光度计法测定大鼠血浆中CO含量;用原位杂交观察GABABR亚基mRNA和c-fos基因表达情况;用免疫组化方法观察GABABR亚基和Fos蛋白表达情况。结果：FS+血晶素组CO含量较FS组升高,GABABR1和GABABR2表达也高于FS组。FS+锌原卟啉Ⅸ组CO含量较FS组降低,其GABABR2表达亦低于FS组,而GABABR1表达与FS组相比差异无显著性。血晶素的干预使c-fos基因和Fos蛋白表达降低,而锌原卟啉Ⅸ的干预使其表达增强。结论：CO可通过调节GABABR的功能在反复热性惊厥中发挥作用。

Abstract:

OBJECTIVE: Some studies have found that both heme oxygenase (HO) /carbon monoxide (CO) system and γ-aminobutyric acid B receptor subunits are involved in the pathogenesis of febrile seizure (FS). The aim of the study was to explore the effect of HO/CO system on GABA_BR subunits during FS. METHODS: Thirty-two Sprague-Dawley rats aged 21 days were randomly assigned into four groups: Control (37.0℃ water), FS, FS+hemin and FS+ZnPPⅨ groups (n=8 each). FS was induced in the last three groups by exposure to a hot water bath (45.0℃ water).Hemin(50 mg/ kg) and ZnPPⅨ(45 μmol/ kg) were intraperitoneally injected half an hour after the water bath in the FS+hemin and FS+ZnPPⅨ groups respectively. The Control and FS groups were administered with normal saline instead. The plasma level of CO was detected by the dual wavelengh spectrophotometer. The expressions of GABA_BR subunit mRNA and c-fos gene were examined by in situ hybridization. The expressions of GABA_BR subunit and Fos protein were observed by immunohistochemistry. RESULTS: The CO content in the FS group was significantly higher than that of the Control group. Hemin treatment increased the CO content while ZnPPⅨ treatment decreased the CO content.The expressions of GABA_BR_2 and GABA_BR_1 increased in the FS+hemin group compared with those in the FS group. In the FS+ZnPPⅨ group, the expression of GABA_BR_2 decreased while the GABA_BR_1 expression was not different compared with that in the FS group.Hemin treatment decreased the expression of c-fos gene and Fos protein, while ZnPPⅨ treatment elevated their expression. CONCLUSIONS: CO may play a role in the pathogenesis of FS through regulating GABA_BR function.