大鼠癫痫持续状态后海马组织各区脑红蛋白表达的实验研究

Study on the expression of NGB in hippocampus after status epliepticus in rats

目的观察大鼠癫痫持续状态(Status epilepticus,SE)后海马组织脑红蛋白(Neuroglobin,NGB)表达动态变化,探讨NGB在癫痫发作中的作用。方法健康成年雄性SpragueDawley大鼠40只,随机分为对照组(n=5)、癫痫模型实验组(n=35);实验组再依据观察时间分为:0、1、3、12、24 h和10、30 d。应用锂-匹罗卡品(20~127 mg/kg)建立大鼠SE模型,观察大鼠致痫期间行为学变化;采用尼氏(Nissl)染色检测海马组织神经元损伤情况;SABC免疫组化法检测海马组织NGB表达水平。结果 SE后,海马组织各区均出现不同程度神经元细胞损伤坏死,随着发作时程进展,CA1、CA3区存活神经元呈近直线下降趋势。其中CA1区(12、24 h,10、30d)、CA3区(0、12、24 h,10、30 d)和(DG区12、24 h,10、30 d)神经元存活数较对照组明显减少(P<0.05)。大鼠SE后,海马各区NGB表达水平均上调,CA1、DG区NGB表达均于SE后24 h达顶峰后轻度下降,但仍持续高于对照组,CA3区NGB表达呈持续升高趋势。其中CA1区(24 h,10、30 d)、CA3区(24 h,10、30 d)和DG区(12、24 h,10、30 d)NGB表达水平均较对照组显著升高(P<0.05)。另外,海马CA1和CA3区神经元存活数与NGB表达水平呈正相关(R=0.206,P=0.015;R=0.306,P=0.011)。结论大鼠SE后海马各区NGB表达上调,且与CA1、CA3区神经元存活数呈正相关,提示NGB表达上调可能是癫痫发作所致缺血缺氧损害的一种代偿保护机制,参与癫痫相关神经元损害的保护。

Objective To observe the dynamic changes of neuroglobin( NGB) expression in hippocampus after status epilepticus( SE) in rats,and to explore the role of NGB in epileptic seizures.Methods 40 healthy male Sprague Dawley rats were randomly divided into two group according to random number table method: control group( n = 5) and epilepsy model group( n = 35). Epilepsy model group according to observation time was divided into: 0h,1h,3h,12 h,24h,10 d and 30 d. Intraperitoneal injection Lithium-pilocarpine( 20 mg/kg ~ 127 mg/kg,Li-PC) to establish the rat model of SE. Observe the behavioral changes in rats with epilepsy. Nissl staining was used to detect the neuronal damage in hippocampus. Streptavidin-biotin-peroxidase complex immunohistochemical method was used to detect the expression level of NGB in hippocampus; Results After SE,the neurons in hippocampus were severely damaged with the progress of epileptic seizures,the number of surviving neurons in CA1,CA3 regions showed a near linear decline. Among them,the number of surviving neurons in( 12 h,24h,10 d,30d) CA1,( 0h,12 h,24h,10 d,30d) CA3 and( 12 h,24h,10 d,30d) DG area were significantly lower than that of the control group( P < 0. 05). The expression level of NGB in CA1,CA3 and DG region of hippocampus were increased after SE,and both of CA1 and DG were reached peak in 24 h after SE,but was still higher than the control group. And the CA3 area showed a continue rising trend. Among them,CA1( 24 h,10d,30d),CA3( 24 h,10d,30d) and DG( 12 h,24h,10 d,30d) were higher than that of control group significantly( P < 0. 05). In addition,it was found that there was a positive correlation between the number of surviving neurons in CA3 area and the expression level of NGB( R = 0. 306,P = 0. 011). Conclusion Upregulation of NGB expression in hippocampus after status epilepticus,and was positively correlated with the number of neurons in the CA3 area,suggesting that up regulation of NGB expression may be a compensatory protective mechanism of ischemic injury induced by seizures,and participate in the protection of epilepsy related neuronal damage.