脑源性神经营养因子对大鼠惊厥性脑损伤的作用及调控因素

目的观察外源性脑源性神经营养因子（BDNF）、磷酸化cAMP反应元件结合蛋白（pCREB）在活体内对海马BDNF表达的影响及其与神经元凋亡间的关系。方法80只Wistar大鼠,选取40只作为持续惊厥状态（SC）组,制作Wistar鼠SC模型,进一步分为SC-对照亚组（脑室内不注射）、SC-NS亚组（脑室内注射生理盐水）、SC-BDNF亚组（脑室内注射BDNF）和SC-抗pCREB抗体亚组（脑室内注射抗pCREB抗体）,每组各10只大鼠。余下40只大鼠作为对照（NC）组,不制备SC模型,进一步分组和处理方法同SC组。采用ELISA检测海马BDNF含量（pg·μg^-1）,Annexin-V检测海马细胞凋亡。结果①NC-BDNF亚组,注射侧海马BDNF含量为17.24±2.23,明显高于NC-对照亚组5.91±1.63;与NC-对照亚组相比,SC-对照亚组BDNF含量增高,达13.37±5.61。与SC-NS亚组相比,SC-BDNF亚组海马BDNF含量达55.40±4.11,呈显著性增高（P〈0.01）,同时,该侧海马细胞凋亡发生率从（8.36±0.61）%降低至（4.10±1.00）%（P〈0.01）。②NC-抗pCREB抗体亚组注射侧海马BDNF含量为5.94±0.60,与NC-对照亚组差异无统计学意义。与SC-NS亚组（15.77±2.99）相比,SC-抗pCREB抗体亚组注射侧海马BDNF含量急剧下降,为5.53±1.11,并伴有该侧海马细胞凋亡发生率的增加,由（8.36±0.61）%增至（9.37±2.50）%。③脑室内注射将诱导注射侧海马神经细胞凋亡,而对注射对侧海马影响不大。结论①脑室内注射外源性BDNF可影响同侧海马内源性BDNF表达,并对神经元凋亡有一定抑制作用。②选择性阻断CREB的磷酸化,可能通过抑制BDNF的表达,导致神经细胞凋亡。

Action of brain-derived neurotrophic factor on brain damage induced by status convulsion in rats

Objective To investigate whether the exogenous BDNF or the phosphorylation of cAMP response elementbinding protein（pCREB） influence the hippocampal BDNF expression and the apoptotic procedure in vivo. Methods Seizures were induced in ARs with lithium and pilocarpine injected intraperitoneally. The rats were intraventricular （IV） injected with BDNF or anti-pCREB antibody after SC, and sacrificed 1 d later. The levels of BDNF in both hippocampi were determined by quantitative ELISA（pg · μg^-1 ）. The apoptotic ceils was quantified by the Annexin V-FITC apoptosis detection. The expression of pCREB in hippocampus 30 min after SC was observed by semiquantitative immunohistochemistry. Results ① In the normal control group, there was no significant alteration for BDNF levels in the lateral received IVI NS or anti-pCREB antibody, but the BDNF level in the lateral received IVI-BDNF was much higher than that in the non-IVI group and NS-IVI group（P 〈0.01 ）. The expression of BDNF was obviously increased in rat hippocampus after SC（P 〈 0.01 ）. The administration of IVI NS did not cause marked change of BDNF levels in the lateral received IVI after SC. The level of BDNF in the hippocampus of the lateral received IVI BDNF （0.4 μg）was significantly increased in the normal group and SC group, and was much higher in SC group （55.40 ±4.11 ） compared with the normal group （ P 〈 0.01 ）. Among the SC experimental groups, the BDNF levels were the highest in BDNF- IVI group. The level of BDNF in the lateral received IVI anti-pCREB antibody（ 400 μg） was dropped dramatically（P 〈 0.01 ）in the SC group compared with that in the other SC experimental group（ non-IVI control group, NS-IVI group, BDNF-IVIgroup, P 〈0. 01 ）and that in the blank control group（ P 〉 0. 05 ）. In the lateral received IVI anti-pCREB antibody in the normal group , BDNF level was not significantly increased compared with the blank control （5.94 ±0.60, 5.91 ± 1.63, respectively）. The intraventricular