Abstract：
Previous studies have confirmed the relationship between chloride homeostasis and pain. However, the role of sodium potassium chloride co-transporter isoform 1 (NKCC1) in dorsal horn and dorsal root ganglion neurons (DRGs) in spinal cord injury (SCI)-induced neuropathic pain (NP) remains inconclusive. Therefore, we aimed to explore whether suppression of NKCC1 in the spinal cord and DRGs alleviate the NP of adult rats with thoracic spinal cord contusion. Thirty adult female Sprague-Dawley rats (8 week-old, weighing 250-280 g) were randomly divided into three groups with ten animals in each group (sham, SCI, and bumetanide groups). The paw withdrawal mechanical threshold and paw withdrawal thermal latency were recorded before injury (baseline) and on post-injury days 14, 21, 28, and 35. At the end of experiment, western blotting (WB) analysis, quantitative real-time Polymerase Chain Reaction (PCR) and immunofluorescence were performed to quantify NKCC1 expression. Our results revealed that NKCC1 protein expression in the spinal cord and DRGs was significantly up-regulated in rats with SCI. Intraperitoneal treatment of bumetanide (an NKCC1 inhibitor) reversed the expression of NKCC1 in the dorsal horn and DRGs and ameliorated mechanical ectopic pain and thermal hypersensitivities in the SCI rats. Our study demonstrated the occurrence of NKCC1 overexpression in the spinal cord and DRGs in a rodent model of NP and indicated that changes in the peripheral nervous system also play a major role in promoting pain sensitization after SCI.
摘要：
先前的研究已经证实了氯化物稳态与疼痛之间的关系。然而,在脊髓损伤（SCI）诱导的神经性疼痛（NP）中，背角和背根神经节神经元（DRG）中氯化钠钾辅助转运蛋白亚型1（NKCC1）的作用仍不确定。因此,我们旨在探讨脊髓中NKCC1和DRGs的抑制是否减轻成年大鼠胸脊髓挫伤的NP。30只成年雌性Sprague-Dawley大鼠（8周龄，体重250-280克)，随机分为三组，每组10只动物(假手术，SCI和布美他尼组)。在损伤前(基线)和损伤后第14、21、28和35天记录爪缩回机械阈值和爪缩回热潜伏期。实验结束时,蛋白质印迹分析,进行定量实时PCR和免疫荧光以定量NKCC1表达。我们的结果表明，SCI大鼠脊髓和DRGs中NKCC1蛋白的表达显着上调。布美他尼（NKCC1抑制剂）的腹膜内治疗逆转了脊髓背角和DRGs中NKCC1的表达，并改善了SCI大鼠的机械性异位疼痛和热超敏反应。我们的研究表明，在NP的啮齿动物模型中，脊髓和DRGs中NKCC1过表达的发生，并表明周围神经系统的变化在SCI后促进疼痛敏化方面也起着重要作用。
