钙结合蛋白与颞叶癫痫大鼠海马神经元易损性的关系研究

Study of the relationship between calcium-binding proteins and neuronal vulnerability in temporal lobe epileptic rats

目的探讨微白蛋白(Parvalbumin,PV)、钙视网膜蛋白(Calretinin,CR)、钙结合蛋白-D28K(Calbindin-D28k,CB)与颞叶癫痫大鼠海马神经元易损性的关系及在颞叶癫痫的发生发展中的作用。方法采用氯化锂-匹罗卡品颞叶癫痫大鼠模型,应用免疫组化动态观察海马神经元内PV、CR、CB的表达。结果实验组大鼠PV阳性中间神经元的数量在CA3区无明显变化(P>0.05);在CA1区,呈进行性下降,到7d时达最低值(P<0.01);在齿状回及门区,先进行性下降,15d时达最低值(P<0.01),30d后开始上升,到60d几乎达正常水平(P>0.05)。大鼠各区CR阳性中间神经元的数量较对照组均明显下降;在CA3区,急性期和慢性期下降最明显(P<0.01);在CA1区24h组的数量最少(P<0.01);在齿状回的门区15d组的数量最低(P<0.01)。CB阳性中间神经元的数量在CA3区与对照组无明显变化(P>0.05);在CA1区,6h后开始减少(P<0.05),7d后达最低值(P<0.01),然后稍有回升,但仍明显低于对照组(P<0.05);门区CB阳性中间神经元的数量较对照组增加(P<0.05)。结论氯化锂-匹罗卡品颞叶癫痫动物模型中海马内含PV、CR、CB的GABA能中间神经元存在选择性易损性,CA1区含PV、CR、CB的GABA能中间神经元的急剧减少可能诱发了颞叶癫痫的急性发作;含PV、CB的GABA能中间神经元在齿状回的改变可能在颞叶癫痫自发性复发性发作的发生和发展中扮演了非常重要的角色。

Objective To systemically discuss the relationships between Parvalbumin （ PV）, Calretinin （ CR）, Calbindin-D28k （CB） and neuronal vulnerability, and the role of PV, CR, CB in the acute onset and development of temporal lobe epilepsy. Methods Methods Immunohistochemistry was used to detect the changes of the PV, CR, CB-containing interneuran numbers in the hippocampus of lithium-pilocarpine induced temporal lobe epileptic rats at different time points （6h, 24h,7d,15d,30d,60d）. Results No significant change was observed in any region at any time point in control group. In lithium-pilocarpine treated rats, no loss of PV-positive cells was observed in the CA3 region at any time point; while dramatic reduction was seen in CAl region. In dentate gyrus and hilus,PV-positive interneurons were lost in acute and silent stage, then increased to almost normal level in chronic stage. The numbers of CR positive interneurons decreased in all regions following the onset of status epilepticus（SE）. The dramatic reduction was seen in CA1 and CA3 regions at 24h;and in DG at 15d. No significant changes of CB positive intemeurons in CA3 region were found at any time point compared with those of the control group. In CA1 region, the number of CB positive interneurons decreased dramatically;while in DG, CB positive interneurons increased significantly. Conclusion Selective vulnerability of PV-,CR-, CB-containing GABAergic interneurons exists in the hippocampal formation of the lithium-pilocarpine model of temporal lobe epilepsy. The rapid reduce of PV-, CR-, CB-containing GABAergic interneurons in CA1 region may induce the acute onset of epilepsy,while the changes of PV-, CB-containing GABAergic interneurons in DG may play an important role in the expression and development of spontaneous recurrent seizures（SRS）.