戊四氮诱导发育鼠癫癎持续状态后海马神经发生及MK-801的影响

Neurogenesis of hippocampus following pentylenetrazol-induced status epilepticus in developing rats and the effect of MK-801 on neurogenesis

摘要:

目的：探讨戊四氮诱导发育期大鼠癫癎持续状态(SE)后对海马内齿状回颗粒细胞神经发生的影响以及N-甲基D-天冬氨酸受体(NMDAR)拮抗剂MK-801对此结果的抑制作用,从而研究癫癎发作后发育脑海马内神经发生及NMDAR在神经发生中的作用。方法：SD大鼠7,14,21,28d4个日龄组共216只,每组均为54只,每个日龄组大鼠随机分SE组、MK-801组和正常对照组,每组18只。采用5-溴脱氧尿核苷(BrdU)标记新生细胞,再以β微管蛋白Ⅲ(TuJ1)、胶质原纤维酸性蛋白(GFAP)分别标记早期神经元和胶质细胞的单、双标免疫组织化学方法,检测PTZ诱导癫癎持续状态后发育鼠海马齿状回(dentategyrus,DG)神经发生,并用MK-801治疗后观察对其的影响。结果：BrdU注射后第7天和第14天,SE组各日龄幼鼠齿状回BrdU阳性细胞数明显高于同日龄的正常对照组,其中约有80%同时表达TuJ1;MK-801组BrdU阳性细胞数较SE组明显减少(P<0.01),而在第28天三组之间BrdU阳性细胞数无明显差异(P>0.05)。结论：癫癎发作可增加幼鼠齿状回颗粒细胞的神经发生,而NMDAR在癫癎后的神经发生中起着促进作用。

Abstract:

OBJECTIVE: This study aimed to determine whether pentylenetetrazol-induced status epileticus (SE) can induce dentate granule cell neurogenesis in the developing rat and the effect of MK-801, a noncompetitive antagonism of N-methy-D-aspartate receptor (NMDAR), on neurogenesis. METHODS: Two hundred and sixteen postnatal days 7, 14, 21 or 28 Sprague Dawley (SD) rats were involved in this study. Each age group consisted of 54 rats which were randomly assigned into a SE group, a SE+MK-801 group and a Normal control group (n=18 each). SE was induced by intraperitoneal injection of PTZ (80 mg/kg). The SE+MK-801 group was injected intraperitoneally with MK-801 ( 1 mg/kg ) at 1 hr after SE episode. All rats were given 5-bromodeoxyuridene (BrdU) intraperitonealy to label newborn cells at 6, 13 and 27 days after seizures and then were sacrificed 24 hrs after BrdU injection. The immunohischemistry method was used to measure the expression of BrdU, TuJl (βIII tubulin), and glial fibrillary acidic protein (GFAP) in the dentate gyrus of hippocampus of rats. RESULTS: The number of the BrdU positive cells in the SE group was significantly higher than in the age-matched normal controls at 7 and 14 days after SE episode (P<0.05 or 0.01). Approximately 82.5% and 80.3% of BrdU-labeled cells in the SE and the Control groups were co-expressed TuJ1 respectively. MK-801 treatment decreased the BrdU positive cells compared with the SE group at 7 and 14 days after SE seizures (P< 0.01 ). On the 28th day after SE episode there were no differences among the three groups for the BrdU positive cells. CONCLUSIONS: PTZ -induced SE can increase the dentate granule cell neurogenesis in the developing rat. NMDAR plays an important role in neurogenesis following seizures.