Munakata Mitsutoshi, Watanabe Mika, Otsuki Taisuke, Nakama Hideyuki, Arima Kunimasa, Itoh Masayuki, Nabekura Junichi, Iinuma Kazuie, Tsuchiya Shigeru
Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan.
Epilepsia. 2007 Apr;48(4):837-44. doi: 10.1111/j.1528-1167.2006.00954.x. Epub 2007 Feb 5.
To examine the distribution of KCC2, a neuron-specific K(+)-Cl(-) cotransporter, in human cortical dysplasia (CD).
The immunohistochemical expression of KCC2 was investigated in 18 CD specimens obtained during epilepsy surgery. The histopathologic diagnoses were focal CD (FCD) type I (eight cases), FCD type II (six cases), and hemimegalencephaly (HME; four cases). Tissue sections were immunostained for KCC2 and compared with control sections.
In the mature nondysplastic cortex, all the layers showed diffuse neuropil staining for KCC2. The somata were stained much less, although subcortical ectopic neurons displayed dense staining in the cytosol (intrasomatic staining). In FCD type I, the cortex showed neuropil staining for KCC2 with less-stained somata. Aberrant giant pyramidal neurons were also less stained at the soma, whereas immature neurons showed intrasomatic staining. Increased numbers of ectopic neurons with intrasomatic staining were noted in the subcortical white matter. In FCD type II, dysmorphic neurons displayed dense intrasomatic staining with reduced staining of the neighboring neuropils. Balloon cells did not stain for KCC2. Dysmorphic neurons in HME also showed intrasomatic staining.
Neurons in CD tissues expressed KCC2. However, the subcellular distribution of KCC2 was altered, which might have affected the ionic homeostasis of Cl(-) and K(+) involved in epileptic activity within CD tissues.
研究神经元特异性钾氯共转运体2（KCC2）在人类皮质发育异常（CD）中的分布。
对癫痫手术中获取的18例CD标本进行KCC2免疫组化表达研究。组织病理学诊断为I型局灶性皮质发育异常（FCD）（8例）、II型FCD（6例）和半侧巨脑畸形（HME；4例）。对组织切片进行KCC2免疫染色，并与对照切片进行比较。
在成熟的非发育异常皮质中，所有层均显示KCC2的弥漫性神经纤维染色。胞体染色较少，尽管皮质下异位神经元在胞质溶胶中显示密集染色（胞内染色）。在I型FCD中，皮质显示KCC2的神经纤维染色，胞体染色较少。异常的巨大锥体细胞在胞体处染色也较少，而未成熟神经元显示胞内染色。在皮质下白质中发现胞内染色的异位神经元数量增加。在II型FCD中，畸形神经元显示密集的胞内染色，相邻神经纤维的染色减少。气球样细胞不着色KCC2。HME中的畸形神经元也显示胞内染色。
CD组织中的神经元表达KCC2。然而，KCC2的亚细胞分布发生了改变，这可能影响了CD组织中参与癫痫活动的氯离子（Cl⁻）和钾离子（K⁺）的离子稳态。
