葡萄糖-6-磷酸脱氢酶对皮层注射FeCl_3所致早期癫痫的保护作用

Glucose-6-phosphate dehydrogenase protects early epilepsy in rats after intracortical injection of ferric chloride

目的探讨葡萄糖-6-磷酸脱氢酶(glucose-6-phosphate dehydrogenase,G6PD)在外伤后早期癫痫中的脑保护作用。方法采用大脑皮层微量注射FeCl3溶液建立癫痫大鼠动物模型。将24只SD大鼠抽签随机分为对照组、实验组、干预组(n=8),对照组和实验组腹腔注射灭菌花生油10 ml/kg,干预组腹腔注射浓度为0.1μg/ml的G6PD激动剂1,25-(OH)2D3 1μg/(kg.d),连续7 d后,对照组为皮层注射pH为1.5的生理盐水5μl,实验组和干预组皮层注射100 mmol/LFeCl3 5μl。所有大鼠皮层注射后行脑电监测2 h,行为学观察6 h后处死;利用RT-PCR、Western blot检测皮层脑组织G6PD表达,比色法检测大脑皮层脂质过氧化的主要代谢产物丙二醛(malondialdehyde,MDA)含量和抗氧化水平的还原型谷胱甘肽(glutathione,GSH)的含量以及G6PD活性。结果实验组、干预组均出现典型的痫性发作,与实验组比较,干预组癫痫发作次数少(5.14±3.27)次、且持续时间短(4.37±4.94)min(P<0.05);干预组皮层G6PD mRNA及蛋白表达水平均高于实验组(P<0.05),但仍低于对照组(P>0.05);与实验组比较,干预组G6PD活性、GSH含量增高(P<0.05),MDA的含量显著降低(P<0.05)。结论 G6PD可提高大鼠脑皮层的抗氧化能力,对FeCl3所致的早期癫痫有一定的保护作用。

Objective To determine the cerebral protective effect of glucose-6-phosphate dehydrogenase（G6PD） in rat early epilepsy.Methods Twenty-four SD rats were randomly and equally divided into 3 groups,normal control,model group and intervention group.The rats of intervention groups received an intraperitoneal injection of 0.1 μg/ml 1,25-dihydroxyvitamin D3（1,25-（OH）2D3） for 7 d,and the animals of the normal control and model group were administered with an intracortical injection of normal saline.Rat models of epilepsy were established by intracortical microinjection of ferric chloride and identified by electroencephalography（EEG） in 2 h later and occurrence of seizures by behavior observation in 6 h later.Expression of G6PD mRNA and protein were detected in the cerebral cortex by RT-PCR and Western blotting.Malondialdehyde（MDA） level of lipid peroxidation and antioxidant level of glutathione（GSH） and G6PD activity were detected by colorimetric method.Results Typical seizures were observed in model and intervention groups.The seriousness and duration of epilepsy seizures of rats from intervention group were less obvious than those of model groups（P0.05）.The expressions of G6PD mRNA and protein in injection zone of cortex from intervention groups were higher than those in the model groups（P0.05）,but lower than those in the control groups（P0.05）.The G6PD activity and GSH level were increased（P0.05） but the MDA level was significantly reduced in the intervention groups（P0.05）.Conclusion G6PD can improve the antioxidant capacity of brain cortex and protect rats from the FeCl3-induced epilepsy.