Cai Xiao-tang, Cai Fang-cheng
Department of Neurology, Children's Hospital, Chongqing University of Medical Science, Chongqing 400014, China.
Sichuan Da Xue Xue Bao Yi Xue Ban. 2005 Jul;36(4):541-4.
To explore the age character of the activity of Caspase 3 and neuron death induced by LiCl-pilocarpine status epilepticus.
LiCl-pilocarpine was injected into healthy infant rats (19 days) and adult rats (2-3 months) subcutaneously and intra-abdominally to evoke status epilepticus (SE). First, the age difference of the seizure was used to measure the sensitivity of seizure. Second, the dynamic features of the apoptotic neurons and the activity of Caspase 3 at 15, 30 min and 1, 2, 4, 8 hours after SE respectively were investigated by TUNEL, flow cytometry and fluorospectrophotometry.
(1) The average duration from the injection to seizure was (13.3 +/- 5.63) min in infant rats, and (22.5 +/- 5.66) min in adult rats. (2) The proportion of the 4th or 5th degree of severity at onset of seizure was 68% in infant rats and 18% in adult rats. (3) Although the count of died neurons (in the CA3 of hippocampus, dentate gyrus and cortex of temporal lobe) was physiologically higher in normal infant rats than in adult rats, the count of positive neurons by TUNEL stain in mature brain (524 +/- 26) remarkably increased and exceeded that in premature brain (465 +/- 26) at 30 min after SE. Although continuously observed until 8 hours after SE, the count of apoptotic neurons in mature brain was also remarkably higher than that in infant brain. Change of neurons in apoptotic early events detected by flow cytometry was the same as the result of TUNEL. (4) The increasing proportion of activity of Caspase 3 after SE for 30 min in adult rats remarkably exceeded that in infant rats; it was 0.10 +/- 0.07 in adult rats and 0.003 +/- 0.04 in infant rats. The difference between the infant rats (0.39 +/- 0.20) and adult rats (0.10 +/- 0.20) increased after SE for 2 hours.
A mechanism of inhibiting apoptotic process in premature brain during SE for the protection against brain damage was well reconfirmed by different animal SE models induced by lithium-pilocarpine. It was indicated that the protective mechanism against brain damage in premature brain could be presented in most severe seizures of different types. This protective mechanism could act on the apoptotic occurrence in the earlier period before the activation of Caspase cascade reaction.
探讨氯化锂-匹罗卡品致癫痫持续状态诱导的Caspase 3活性及神经元死亡的年龄特征。
将氯化锂-匹罗卡品分别经皮下和腹腔注射入健康幼龄大鼠（19日龄）和成年大鼠（2 - 3月龄）诱发癫痫持续状态（SE）。首先，利用癫痫发作的年龄差异来衡量癫痫敏感性。其次，分别在SE后15、30分钟以及1、2、4、8小时，通过TUNEL法、流式细胞术和荧光分光光度法研究凋亡神经元的动态特征及Caspase 3活性。
（1）幼龄大鼠从注射到发作的平均持续时间为（13.3±5.63）分钟，成年大鼠为（22.5±5.66）分钟。（2）癫痫发作起始时4级或5级严重程度的比例在幼龄大鼠中为68%，成年大鼠中为18%。（3）虽然正常幼龄大鼠海马CA3区、齿状回和颞叶皮质中死亡神经元的数量在生理上高于成年大鼠，但在SE后30分钟，成熟脑（524±26）中TUNEL染色阳性神经元的数量显著增加并超过未成熟脑（465±26）。尽管持续观察至SE后8小时，成熟脑中凋亡神经元的数量仍显著高于幼龄脑。流式细胞术检测的凋亡早期事件中神经元的变化与TUNEL结果相同。（4）SE后30分钟成年大鼠Caspase 3活性增加的比例显著超过幼龄大鼠；成年大鼠为0.10±0.07，幼龄大鼠为0.003±0.04。SE后2小时幼龄大鼠（0.39±0.20）与成年大鼠（0.10±0.20）之间的差异增大。
通过氯化锂-匹罗卡品诱导的不同动物SE模型再次充分证实了在SE期间未成熟脑抑制凋亡过程以保护脑损伤的机制。表明未成熟脑对脑损伤的保护机制可在不同类型的最严重癫痫发作中呈现。这种保护机制可作用于Caspase级联反应激活之前的早期凋亡发生阶段。
