Yang Q, Wang S, Hamberger A, Haglid K G
Department of Anatomy and Cell Biology, University of Göteborg, Sweden.
Neurosci Res. 1996 Sep;26(1):57-64. doi: 10.1016/0168-0102(96)01077-2.
Abnormal reestablishment of mossy fibers with the CA3 pyramidal cells and granule cells is an important aspect of postlesional plasticity in epilepsy. However, basis for the structural reorganisation and functional consequences of the event remain uncertain. Therefore we have investigated alterations of neurofilaments, major cytoskeletal components of neurons, in the rat hippocampus after the kainic acid (KA) administration, an experimental model for the temporal lobe epilepsy. The immunoreactivity for phosphorylated heavy weight neurofilament (pNFH) and non-phosphorylated heavy weight neurofilament (npNFH), in particular the pNFH, decreased in the CA1 field and inner molecular layer of the dentate gyrus during 3 and 10 days after the KA administration. After 10 days, npNFH immunoreactivity appeared in the mossy fibers, in which it is normally absent, meanwhile the pNFH staining in the mossy fibers did not decrease. From day 21, the immunoreactivity of pNFH and npNFH was normal or above normal in the CA1 stratum lacunosum-moleculare, mossy fibers, hilus and inner molecular layer of the dentate gyrus. These alterations in the later phase remained at least to day 90. The reappearance and increase of the neurofilament immunoreactivity in the inner molecular layer of the dentate gyrus probably reflects a collateral extension of the granule cell axons known as mossy fiber sprouting. The results suggest that neurofilament changes in the granule cell-mossy fiber system may be a morphological basis for the structural reconstruction of granule cell axons, and neurofilaments are involved in the plasticity after the KA induced seizures.
苔藓纤维与CA3锥体细胞和颗粒细胞的异常重新建立是癫痫病灶后可塑性的一个重要方面。然而，该事件的结构重组基础和功能后果仍不确定。因此，我们研究了在颞叶癫痫实验模型——给予 kainic 酸（KA）后大鼠海马体中神经丝（神经元主要细胞骨架成分）的变化。在给予 KA 后的第3天和第10天，磷酸化重链神经丝（pNFH）和非磷酸化重链神经丝（npNFH）的免疫反应性，特别是pNFH，在齿状回的CA1区和内分子层中降低。10天后，npNFH免疫反应性出现在正常情况下不存在的苔藓纤维中，同时苔藓纤维中的pNFH染色并未降低。从第21天起，pNFH和npNFH在齿状回的CA1腔隙-分子层、苔藓纤维、海马和内分子层中的免疫反应性正常或高于正常。后期的这些变化至少持续到第90天。齿状回内分子层中神经丝免疫反应性的重新出现和增加可能反映了称为苔藓纤维出芽的颗粒细胞轴突的侧支延伸。结果表明，颗粒细胞-苔藓纤维系统中的神经丝变化可能是颗粒细胞轴突结构重建的形态学基础，并且神经丝参与了KA诱导癫痫发作后的可塑性。
