大鼠海马线粒体解偶联蛋白-4在热性惊厥后的表达

Changes of uncoupling protein-4 expression after febrile seizures in the hippocampus of developing rats

摘要:

目的：人类热性惊厥多发生于 6个月～ 5岁的儿童。小儿热性惊厥的发生率随体温上升明显升高 ,惊厥发生时体温为 38.0～ 4 2℃。但是热性惊厥的病理生理机制目前仍不明确。该实验拟通过研究热性惊厥(febrileseizures ,FS)对发育期大鼠脑内海马区神经元线粒体解偶联蛋白UCP4表达的影响 ,探讨热性惊厥过程中细胞能量代谢的变化。方法：采用热水浴诱导大鼠热性惊厥模型。72只发育期大鼠分为 3组 :对照组 (n =2 4 ) ,热性惊厥组 (n =2 4 ) ,高热未惊厥组 (n =2 4 )。该实验通过免疫组化、原位杂交两种定性实验 ;以及Westernblot半定量实验 ,测定大鼠海马UCP4在热性惊厥后的含量的变化。结果：惊厥组大鼠脑内海马区神经元细胞内UCP4的蛋白含量高于高热组和对照组 ,高热组UCP4的表达低于惊厥组和对照组。与对照组 (14 830 .75± 6 4 1.91)相比 ,热性惊厥组IDV/area值增高 (2 2 15 0 .6 3± 4 2 3.4 ) (P <0 .0 5 ) ,而高热组的IDV/area值降低 (10 5 11.6 3± 30 2 .0 7)(P <0 .0 5 )。结论：热性惊厥可能导致解偶联蛋白表达增多 ,作用增强 ,热能释放增多 ,基础代谢率增高 ,防止活性氧族 (ROS)的形成 ;同时ATP的产生减少 ,可能反复的热性惊厥影响了线粒体能量储备的功能。

Abstract:

OBJECTIVE: Febrile seizures (FS) occur more frequently in children between the ages of six months and five years, especially when they have a fever (38-42℃). The pathophysiological mechanism for FS is not clear at the moment. To explain the changes of cellular energy metabolism during FS, the expression of uncoupling protein-4 (UCP4) was studied after recurrent FS in the hippocampus using developing rats. METHODS: FS were induced in the rats by exposure to a hot water bath. Seventy-two developing rats were divided into a Control group (n=24), a FS group (n=24), and a Febrile without seizure group (Febrile group, n=24). The mRNA and protein expression of UCP4 in the rat hippocampus was studied after the hyperthermia stimulation using immunohistochemistry, in situ hybridization and Western blot analysis. RESULTS: The UCP4 content in the hippocampus was higher in the FS group than that in both of the Control and Febrile groups, while the UCP4 content in the Febrile group was the lowest among the three groups. The highest mean intergrated density value (IDV) /area was 22 150.63± 423.40 in the FS group, followed by the Control group ( 14 830.75± 641.91) and the Febrile group ( 10 511.63± 302.07) (both P< 0.05). CONCLUSIONS: Increased expression of UCP4 in the FS group suggested an increased uncoupling process in mitochondria. Consequently, recurrent FS could decrease ATP production and affect the mitochondrial reserve function.