过表达硫氧还蛋白-1抑制戊四氮致癫痫大鼠海马神经元细胞凋亡

Overexpression of thioredoxin-1 inhibits apoptosis of hippocampal neurons in pentylenetetrazol-induced epilepsy rats

目的:探讨过表达硫氧还蛋白-1(Trx-1)对戊四氮(PTZ)点燃致癫痫大鼠模型海马神经元细胞凋亡的影响及作用机制。方法:40只SD大鼠随机分为4组:对照组、模型组、Trx-1过表达组和阴性对照组,每组10只。Trx-1过表达或空载慢病毒溶液注射大鼠侧脑,PTZ点燃致痫,观察各组大鼠行为变化,记录癫痫发作时间及级别。HE染色观察海马组织形态学变化,TUNEL染色观察海马组织神经元细胞凋亡水平,RT-PCR检测海马组织中Trx-1 mRNA表达水平,Western blot检测Trx-1、B淋巴细胞瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、凋亡信号调节激酶1(ASK1)及磷酸化c-Jun末端激酶(p-JNK)蛋白表达。结果:与对照组相比,模型组大鼠癫痫发作时间长、级别高,海马组织损伤严重,且神经元细胞凋亡增加。与模型组相比,Trx-1过表达组癫痫发作时间明显缩短,癫痫级别降低,海马组织损伤减轻,细胞凋亡数量减少,Bcl-2表达升高,而Bax、ASK1及p-JNK蛋白表达水平降低。结论:过表达Trx-1对癫痫大鼠模型具有较好的治疗效果,其抑制神经元细胞凋亡的作用机制可能与下调ASK1/JNK通路有关。

Objective:To investigate effect of thioredoxin-1(Trx-1)overexpression on apoptosis of hippocampal neurons in pentylenetetrazol(PTZ)kindled epileptic rats and its mechanism.Methods:40 SD rats were randomly divided into 4 groups:control group,model group,Trx-1 overexpression group and negative control group,with 10 rats in each group.Rats were injected with Trx-1 overexpression or no-load lentivirus solution into lateral brain,PTZ kindled epilepsy.Observed behavior changes of rats in each group,and recorded seizure time and level.HE staining was used to observe morphological changes of hippocampus.TUNEL staining was used to observe apoptotic level of neurons in hippocampus.RT-PCR was used to detect mRNA expression level of Trx-1 in hippocampus.Western blot was used to detect proteins expressions of Trx-1,B-cell lymphoma-2(Bcl-2),Bcl-2 associated X protein(Bax),apoptotic signal regulating kinase-1(ASK1)and phosphor c-Jun N-terminal kinase(p-JNK).Results:Compared with control group,epileptic seizures lasted for a long time and were of high grade in model group,hippocampal tissue was severely damaged,and neuronal cell apoptosis was increased.Compared with model group,seizure duration was significantly reduced,epilepsy level was reduced,hippocampal tissue was severely damaged,neuronal apoptosis was increased,expression of Bcl-2 was increased,and expressions of Bax,ASK1 and p-JNK were decreased in Trx-1 overexpression group.Conclusion:Overexpression of Trx-1 has a good therapeutic effect on epilepsy rat model,and its mechanism of inhibiting neuronal apoptosis may be related to down-regulation of ASK1/JNK pathway.