戊四氮慢性点燃大鼠海马谷氨酸、γ-氨基丁酸阳性细胞变化及柴胡总皂甙的干预作用

Saikosaponins inhibit increased glutamate and GABA expressions in the hippocampus of pentetrazole-induced slow kindling rats

目的研究柴胡总皂甙对戊四氮慢性点燃癫痫模型大鼠海马区谷氨酸(Glu)、γ-氨基丁酸(GABA)细胞表达的影响。方法48只健康SD大鼠被随机均分为6组,即空白组(A组)、生理盐水组(B组)、丙戊酸钠组(C组)和柴胡总皂甙高、中、低3种剂量组(D组、E组、F组),除A组不做处理外,其他各组采用腹腔注射戊四氮慢性点燃造模,造模同时给予丙戊酸钠、柴胡总皂甙高、中、低剂量等不同处理因素,连续4周后取脑组织切片进行Glu、GABA免疫组化染色,从阳性细胞数、灰度值分析结果,并比较其比值的变化。结果Glu结果显示,在海马CA1区B组Glu阳性细胞数高于其他各组,有显著性差异(P<0.05),B组海马各区阳性细胞灰度值低于其它各组,有显著性差异(P<0.05);而在CA2区和DG区,B组阳性细胞数、灰度值与各组无显著性差异;GABA结果显示B组海马CA1、CA2、DG区的阳性细胞数与高于其他各组,有显著性差异(P<0.05),B组海马CA1、CA2、DG区阳性细胞灰度值低于其它各组,有显著性差异(P<0.05);在CA1和CA2区,Glu与GABA阳性细胞数比值,B组与各组差异显著(P<0.05);Glu与GABA阳性细胞灰度比值差异不显著(P>0.05)。结论在本研究中戊四氮点燃大鼠的海马细胞内Glu和GABA表达升高,而且GABA升高显著,柴胡总皂甙可干预Glu和GABA的变化,使之趋于正常,这可能是柴胡总皂甙抗实验性癫痫的途径之一。

Objective To study the effect ofsaikosaponins, the active ingredients of Bupleurum chinense DC. on glutamate and GABA expressions in the hippocampus of slow kindling rats induced by pentetrazole. Methods Forty-eight healthy Sprague-Dawley rats were randomly divided into 6 equal groups, namely the blank control group （group A）, normal saline （NS） group （group B）, sodium valproate group （group C）, and 3 saikosaponins groups of high, medium and small doses （groups D, E, and F, respectively）. The rats in each group other than group A were given corresponding treatments after slow kindling by pentetrazole. After 4 weeks of treatment, the rats were sacrifices and the brain tissues were sampled, sliced and stained by immtmohistochemically, and the results were analyzed according to the positive cell number and gray scale. Results In CA1 region, the glutamate-positive cell number and gray scale of group B was significantly different from the other groups （P〈0.05）, but such difference was not observed in the CA2 and DG （P〉0.05）; In CA1, CA2 and DG of the hippocampus, the GABA-positive cell number of group B was significantly greater but the gray scale lower than those of the other groups （P〈0.05）. In CA1 and CA2 regions of the hippocampus, the glutamate- and GABA-positive cell ratio of group B was significantly lower than that of the other groups （P〈0.05）, but in CA1, CA2, and DG region of the hippocampus, the ratio of gray scale between glutamate- and GABA-positive cells was comparable between the groups （P〉0.05）. Conclusion The expression of glutamate and GABA, especially the latter, increased in chronic kindling rat hippocampus. Saikosaponins intervene in such changes of glutamate and GABA to contain their expressions within normal range, which may be one of the mechanisms of saikosaponins to inhibit slow kindling induced by pentetrazole.