Cells undergoing hypoxia experience intense cytoplasmic calcium (Ca²⁺) overload. High concentrations of intracellular calcium ([Ca²⁺]_i) can trigger cell death in the neural tissue, a hallmark of stroke. Neural Ca²⁺ homeostasis involves regulation by the Na⁺/Ca²⁺ exchanger (NCX). Previous data published by our group showed that a product of the enzymatic depolymerization of heparin by heparinase, the unsaturated trisulfated disaccharide (TD; ΔU, 2S-GlcNS, 6S), can accelerate Na⁺/Ca²⁺ exchange via NCX, in hepatocytes and aorta vascular smooth muscle cells. Thus, the objective of this work was to verify whether TD could act as a neuroprotective agent able to prevent neuronal cell death by reducing [Ca²⁺]_i. Pretreatment of N2a cells with TD reduced [Ca^2+]_i rise induced by thapsigargin and increased cell viability under [Ca^2+]_I overload conditions and in hypoxia. Using a murine model of stroke, we observed that pretreatment with TD decreased cerebral infarct volume and cell death. However, when mice received KB-R7943, an NCX blocker, the neuroprotective effect of TD was abolished, strongly suggesting that this neuroprotection requires a functional NCX to happen. Thus, we propose TD-NCX as a new therapeutic axis for the prevention of neuronal death induced by [Ca²⁺]_i overload.

经历缺氧的细胞会经历强烈的细胞质钙（Ca ²⁺ ）超载。高浓度的细胞内钙 ([Ca ²⁺ ] _i ) 可引发神经组织中的细胞死亡，这是中风的标志。神经 Ca ²⁺稳态涉及 Na ⁺ /Ca ²⁺交换器 (NCX) 的调节。本课题组前期发表的数据显示，肝素酶解聚肝素的产物，不饱和三硫酸二糖（TD；ΔU，2S-GlcNS，6S），可以通过NCX加速肝细胞和肝细胞中Na ⁺ /Ca ²⁺的交换。主动脉血管平滑肌细胞。因此，这项工作的目的是验证TD是否可以作为一种神经保护剂，通过减少[Ca ²⁺ ] _i来防止神经元细胞死亡。用TD预处理N2a细胞可减少毒胡萝卜素诱导的[Ca ^2+] _i升高，并增加[Ca ^2+] _I超载条件和缺氧条件下的细胞活力。使用中风小鼠模型，我们观察到 TD 预处理可减少脑梗塞体积和细胞死亡。然而，当小鼠接受 KB-R7943（一种 NCX 阻滞剂）时，TD 的神经保护作用被消除，强烈表明这种神经保护作用需要功能性 NCX 才能发生。因此，我们建议 TD-NCX 作为预防 [Ca ²⁺ ] _i超载引起的神经元死亡的新治疗轴。