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

摘要

目的：观察幼年大鼠惊厥持续状态（statusconvulsion，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mR－NA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。%[ABSTRACT]AIM:Tostudytheeffectsofbaicalin(BC)onglialfibrillaryacidicprotein(GFAP)andnuclear factor-κB ( NF-κB) expression and neuronal apoptosis in juvenile rat hippocampus after status convulsion ( SC) .METH-ODS: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 immuno-histochemistry .The mRNA expression of GFAP was detected by RT-PCR.The neuronal apoptosis was observed by TdT-mediated dUTP nick end labeling ( TUNEL ) .RESULTS: Compared with NS group , the GFAP positive cells was in-creased 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 or P<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 , sug-gesting that baicalin may protect against the brain damage caused by status convulsion .