Delayed administration of nafamostat mesylate inhibits thrombin-mediated blood–spinal cord barrier breakdown during acute spinal cord injury in rats

作者：Chenxi Zhao, Tiangang Zhou, Xiaoqing Zhao, Yilin Pang, Wenxiang Li, Baoyou Fan, Ming Li, Xinjie Liu, Lei Ma, Jiawei Zhang, Chao Sun, Wenyuan Shen, Xiaohong Kong, Xue Yao, Shiqing Feng · 发表于：Journal of Neuroinflammation · 年份：2022 · DOI：10.1186/s12974-022-02531-w · 被引用次数：36 · 研究领域：Blood Coagulation and Thrombosis Mechanisms、Spinal Cord Injury Research、Platelet Disorders and Treatments

BACKGROUND: Nafamostat mesylate (nafamostat, NM) is an FDA-approved serine protease inhibitor that exerts anti-neuroinflammation and neuroprotective effects following rat spinal cord injury (SCI). However, clinical translation of nafamostat has been limited by an unclear administration time window and mechanism of action. METHODS: Time to first dose of nafamostat administration was tested on rats after contusive SCI. The optimal time window of nafamostat was screened by evaluating hindlimb locomotion and electrophysiology. As nafamostat is a serine protease inhibitor known to target thrombin, we used argatroban (Arg), a thrombin-specific inhibitor, as a positive control in the time window experiments. Western blot and immunofluorescence of thrombin expression level and its enzymatic activity were assayed at different time points, as well its receptor, the protease activated receptor 1 (PAR1) and downstream protein matrix metalloproteinase-9 (MMP9). Blood-spinal cord barrier (BSCB) permeability leakage indicator Evans Blue and fibrinogen were analyzed along these time points. The infiltration of peripheral inflammatory cell was observed by immunofluorescence. RESULTS: The optimal administration time window of nafamostat was 2-12 h post-injury. Argatroban, the thrombin-specific inhibitor, had a similar pattern. Thrombin expression peaked at 12 h and returned to normal level at 7 days post-SCI. PAR1, the thrombin receptor, and MMP9 were significantly upregulated after SCI. The m...