年龄和惊厥持续时间对持续惊厥后大鼠海马细胞线粒体膜电位的影响

Correlation of Age and Duration of Status Convulsivus with Mitochondrial Membrane Potential of Hippocampal Cells in Rats

目的探讨年龄和惊厥持续时间对惊厥持续状态(SC)后海马细胞线粒体膜电位(△Ψm)的影响。方法健康成年(ARs)和生后20d幼龄Wistar大鼠(IRs)各80只,经腹腔注射氯化锂-匹罗卡品分别诱发持续惊厥发作30min(30minSC)和3h(3hSC),在SC后3h～7d的6个不同时点上处死动物,采用流式细胞仪检测海马细胞△Ψm的变化。结果 30minSC后3h,两组大鼠海马细胞△Ψm均降低,6h达到最低点,分别为(6.08±0.43)和(5.70±0.63),明显低于对照组(P<0.01),12h后开始回升。SC后3h、3d、7d,IRs海马细胞△Ψm均高于ARs(P<0.05)。7d时,IRs海马细胞△Ψm已升至正常,而ARs仍低于对照组(P<0.05)。3hSC后3h、6h,两组海马细胞△Ψm均低于30minSC后的相同观察时点(P<0.05)。经偏相关参数分析,在排除年龄的影响后,不同惊厥持续时间与海马细胞△Ψm的变化程度呈正相关(r=0.71,P<0.05)。结论严重惊厥发作可导致海马细胞△Ψm降低。年龄和惊厥持续时间均是影响惊厥后海马细胞△Ψm降低的重要因素。幼年脑内可能存在主动抑制海马细胞△Ψm降低的保护性反应。

Objective To explore the influences of age and duration of status convulsivus（SC）on mitochondrial membrane potential（△Ψm）in hippocampus.MethodsConvulsive seizures for 30 min or 3 h（30 min SC or 3 h SC）were induced in 80 infant（20 d after birth）and 80 adult Wistar rats（IRs ARs respectively）with lithium-pilocarpine ip.The rats were sacrificed at 6 different time points from the 3rd hour to 7th day after SC termination.The mitochondrial △Ψm in hippocampal cells was determined with flow cytometry.ResultsThe mitochondrial △Ψm in hippocampal cells started to decrease at the 3th hour after SC in both IRs and ARs.The bottom level was reached at the 6th hour after SC [（6.08±0.43）in IRs and（5.70±0.63）in ARs）].Both of them were significantly lower than that of control group（P0.01）and began to increase at 12th hour after SC.On the 7th day after 30 minutes SC,the level of mitochondrial △Ψm in IRs increased to the level of control,while the level in ARs was still lower than that of control（P0.05）.At the 3rd hour,the 3rd and the 7th day after SC,the levels of mitochondrial △Ψm in IRs were obviously higher than those in ARs.Compared with the same time point after 30 min SC,the levels of mitochondrial △Ψm at the 3rd and the 6th hour after 3 h SC were much lower in different age groups（P0.05）.Except the effect of the age-related difference,there was a positive correlation between the duration of SC and the changes of mitochondrial △Ψm in partial correlation analysis（r=0.71,P0.05）.ConclusionSevere seizure could induce the mitochondrial △Ψm decreased in hippocampus.Age and duration of SC were important factors associated with the mitochondrial △Ψm decrease.There may be an internal protective response against brain damage in premature brain.