皮质发育障碍模型大鼠海马区阳离子-氯离子转运体基因表达变化的研究

目的探讨阳离子-氯离子转运体NKCCl（内向Na^＋,K^＋-2Cl^-协同运输）、KCC2（外向K^＋-Cl^-协同运输）mRNA在皮质发育障碍致痫机制中的作用。方法在SD大鼠孕17d腹腔内注入卡莫司汀（BCNU）制作皮质发育障碍模型;Nissl染色观察P60 d仔鼠病理变化;P60 d用逆转录-聚合酶链反应（RT—PCR）方法检测两组雄性仔鼠海马区NKCC1、KCC2 mRNA的表达。结果Nissl染色显示海马区域异位细胞异常聚集。实验组海马区NKCC 1mRNA表达明显上调（NKCC1／肌动蛋白的比值,实验组0．70±0．13、对照组0．48±0．09,P〈0．01）,KCC2 mRNA表达明显下调（KCC2／肌动蛋白的比值,实验组0．54±0．10、对照组0．81±0．15,P〈0．01）。结论NKCC1 mRNAE调和KCC2 mRNA下调的共同作用可能与皮质发育障碍致痫密切相关。

Changes of expression of cation-chloride cotransporter genes in hippocampus of cortical dysplasia: experiment with rat

OBJECTIVE: To investigate the roles of cation-chloride cotransporters-Na, K, 2Cl(-) cotransporter-1 (NKCC1) and K(+)-Cl(-) cotransporter-2 (KCC(2)) in the epileptogenesis of cortical dysplasia. METHODS: Six pregnant SD rats were given intraperitoneal injection of 1-3-bis-chloroethyl-nitrosourea (BCNU) on the embryonic day 17 (E17) and gave birth of 56 pups (experimental group) on the day P21. Five pregnant SD rats were given intraperitoneal injection of normal saline and gave birth of 48 pups (control group) on the day E21. Sixty days after birth the brains of 24 male pups in the experimental group and 22 male pups in the control group selected randomly were taken out to isolate the hippocampus. Cresyl-violet staining was applied to observe the histological alterations in the hippocampus. RT-PCR was used to detect the mRNA expression of NKCC1 and KCC2. RESULTS: Cresyl-violet staining revealed heterotopic cell clusters within the hippocampus. RT-PCR showed that the ratio of NKCC1 to beta-actin of the experimental group was 0.70 +/- 0.13, significantly higher than that of the control group (0.48 +/- 0.09, P < 0.01); while the ratio of KCC2 to beta-actin of the experimental group was 0.54 +/- 0.10, significantly lower than that of the control group (0.80 +/- 0.15, P < 0.01). CONCLUSION: The upregulation of NKCC1 mRNA and the concomitant downregulation of KCC2 mRNA may be deeply related to the mechanism of epileptogenicity in cortical dysplasias.