黄芩苷对惊厥持续状态幼年大鼠海马GFAP和NF-κB表达的影响

Effects of baicalin on glial fibrillary acidic protein and nuclear factor-κB expression in juvenile rat hippocampus after status convulsion

目的:观察幼年大鼠惊厥持续状态(status convulsion,SC)后脑组织海马中胶质细胞原纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、核因子κB(NF-κB)的表达及神经细胞凋亡的变化,并探讨黄芩苷(baicalin,BC)对三者的影响。方法:将195只19日龄SD雄性大鼠随机分成生理盐水对照组(NS组)、惊厥持续状态组(SC组)和黄芩苷预处理组(BC组)3组;各组再按处死时点不同随机分为4 h、12 h、24 h、48 h和72 h亚组。采用氯化锂-匹鲁卡品化学点燃法制备幼年大鼠SC模型;应用免疫组化法检测大鼠海马中GFAP和NF-κB蛋白的表达情况,RT-PCR法检测GFAP的mRNA表达,TUNEL法检测神经细胞凋亡数的变化。结果:(1)免疫组织化学法检测显示SC组幼年大鼠海马中GFAP表达增强,与NS组比较差异有统计学意义(P<0.05);与SC组比较,BC组的GFAP表达明显降低,差异有统计学意义(P<0.05);SC组幼年大鼠海马中NF-κB表达增强,与NS组比较差异显著(P<0.05);与SC组比较,BC组的NF-κB表达明显降低(P<0.05)。(2)RT-PCR检测结果显示GFAP的mRNA表达趋势与蛋白基本相似。(3)SC组在惊厥后12 h海马CA1区TUNEL阳性细胞数已显著高于NS组(P<0.01),48 h达峰值,而BC组TUNEL阳性细胞数在12 h^48 h均较SC组显著下降(P<0.05或P<0.01),但仍高于NS组(P<0.05)。结论:SC后大鼠海马GFAP和NF-κB的表达增强。黄芩苷可下调匹鲁卡品致痫大鼠海马GFAP和NF-κB的表达,并使神经细胞凋亡数减少,提示黄芩苷在SC引起的脑损伤时对大鼠有保护作用。

AIM： To study the effects of baicalin（ BC） on glial fibrillary acidic protein（ GFAP） and nuclear factor-κB（ NF-κB） expression and neuronal apoptosis in juvenile rat hippocampus after status convulsion（ SC）. METHODS： One hundred and ninety five juvenile male Sprague-Dawley rats were randomly divided into 3 groups： normal saline pretreatment group（ NS group）,SC group and SC with BC pretreatment group（ BC group）. Each of these 3 groups would be subdivided into 5 subgroups sacrificed at 4 h,12 h,24 h,48 h and 72 h after SC. The rat SC model was prepared by lithium-pilocarpine chemical method. The protein expression of GFAP and NF-κB was detected by the method of immunohistochemistry. The mRNA expression of GFAP was detected by RT-PCR. The neuronal apoptosis was observed by Td Tmediated d UTP nick end labeling（ TUNEL）. RESULTS： Compared with NS group,the GFAP positive cells was increased in SC group（P〈0. 05）. Compared with SC group,the expression of GFAP was significantly reduced in BC group（P〈0. 05）. Compared with NS group,the NF-κB positive cells was increased in SC group（P〈0. 05）. Compared with SC group,the expression of NF-κB was significantly reduced in BC group. RT-PCR showed that the expression trend of GFAP mRNA was similar to that of the protein. Compared with NS group,the TUNEL positive cells in the hippocampus CA1 area in SC group increased significantly 12 h after SC（P〈0. 01）,and reached a peak at 48 h. After the intervention with BC,the TUNEL positive cells decreased significantly between 12 - 48 h after SC（P〈0. 05 orP〈0. 01）,but the number of TUNEL positive cells remained significantly greater than that in NS group（P〈0. 05）. CONCLUSION： The expression of GFAP and NF-κB in the hippocampus increased after SC in rats. Baicalin decreases the expression of GFAP and NF-κB in hippocampus of rats with pilocarpine-induced seizures,and reduces the number of neuronal apoptosis,suggesting that baicalin may protect against the brain damage caused by status convulsion.