Department of Neurology, The First Affiliated Hospital, China Medical University, Shenyang, China; Department of Neurology, The Fourth Affiliated Hospital, China Medical University, Shenyang, China.
Department of Neurology, The First Affiliated Hospital, China Medical University, Shenyang, China.
Neuroscience. 2017 Dec 4;365:83-93. doi: 10.1016/j.neuroscience.2017.09.036. Epub 2017 Sep 28.
Bumetanide is a selective inhibitor of the Na-K-Cl-co-transporter 1(NKCC1). We studied whether bumetanide could affect axonal growth and behavioral outcome in stroke rats. Adult male Wistar rats were randomly assigned to four groups: sham-operated rats treated with vehicle or bumetanide, and ischemic rats treated with vehicle or bumetanide. Endothelin-1 was used to induce focal cerebral ischemia. Bumetanide administration (i.c.v.) started on postoperative day 7 and continued for 3 weeks. Biotinylated dextran amine (BDA) was injected into the right imotor cortex on postoperative day 14 to trace corticospinal tract (CST) fibers sprouting into the denervated cervical spinal cord. Nogo-A, NKCC1, KCC2 and BDNF in the perilesional cortex and BDA, PSD-95 and vGlut1 in the denervated spinal cord were measured by immunohistochemistry and/or Western blot. Behavioral outcome of rats was assessed by the beam walking and cylinder tests. The total length of CST fibers sprouting into the denervated cervical spinal cord significantly increased after stroke and bumetanide further increased this sprouting. Bumetanide treatment also decreased the expressions of NKCC1 and Nogo-A, increased the expressions of KCC2 and BDNF in the perilesional cortex and enhanced the synaptic plasticity in the denervated cervical spinal cord after cerebral ischemia. The behavioral performance of ischemic rats was significantly improved by bumetanide. In conclusion, bumetanide promoted post-stroke axonal sprouting together accompanied by an improved behavioral outcome possibly through restoring and maintaining neuronal chloride homeostasis and creating a recovery-promoting microenvironment by overcoming the axonal growth inhibition encountered after cerebral ischemia in rats.
布美他尼是钠-钾-2 氯共转运蛋白 1（NKCC1）的选择性抑制剂。我们研究了布美他尼是否能影响脑卒中大鼠的轴突生长和行为学结果。成年雄性 Wistar 大鼠被随机分为四组：假手术组给予 vehicle 或布美他尼处理，缺血组给予 vehicle 或布美他尼处理。内皮素-1 用于诱导局灶性脑缺血。布美他尼给药（侧脑室注射）于术后第 7 天开始，持续 3 周。术后第 14 天，将生物素化葡聚糖胺（BDA）注射到右侧运动皮质，以追踪皮质脊髓束（CST）纤维向去神经的颈段脊髓发芽。用免疫组织化学和/或 Western blot 检测皮质损伤区周围 Nogo-A、NKCC1、KCC2 和 BDNF 以及去神经脊髓中的 BDA、PSD-95 和 vGlut1。通过横梁行走和圆筒测试评估大鼠的行为学结果。脑卒中后 CST 纤维向去神经的颈段脊髓的总发芽长度显著增加，布美他尼进一步增加了这种发芽。布美他尼治疗还降低了 NKCC1 和 Nogo-A 的表达，增加了皮质损伤区周围的 KCC2 和 BDNF 的表达，并增强了脑缺血后去神经颈段脊髓的突触可塑性。布美他尼治疗显著改善了缺血大鼠的行为表现。总之，布美他尼促进了脑卒中后的轴突发芽，同时改善了行为学结果，这可能是通过恢复和维持神经元氯离子稳态以及通过克服脑缺血后大鼠轴突生长抑制来创造促进恢复的微环境来实现的。
