Department of Neurosurgery, the First People's Hospital of Jingmen City, Hubei, China.
Neuroreport. 2021 Dec 8;32(17):1341-1348. doi: 10.1097/WNR.0000000000001733.
Neuroinflammation and apoptosis are two key factors contributing to early brain injury (EBI) after subarachnoid hemorrhage (SAH) and are strongly associated with a poor prognosis. Recently, equilibrative nucleoside transporter 1 (ENT1) was emerged to accelerate the severity of inflammation and cell apoptosis in several nervous system diseases, including cerebral ischemia, neurodegeneration and epilepsy. However, no study has yet elaborated the expression levels and effects of ENT1 in EBI after SAH.
Sprague-Dawley rats were subjected to SAH by endovascular perforation. Nitrobenzylthioinosine (NBTI) was intranasally administered at 0.5 h after SAH. The protein expression levels of ENT1, NLRP3, Bcl2, Bax, ACS, Caspase-1, IL-1 were detected by western blot. The modified Garcia score and beam balance score were employed to evaluate the neurologic function of rats following SAH. In addition, hematoxylin-eosin, fluoro-jade C and TdT-mediated dUTP nick-end labeling staining were then used to evaluate brain tissue damage and neuronal apoptosis.
Analysis indicated that endogenous levels of ENT1 were significantly upregulated at 24-hour post-SAH, accompanied by NLRP3 inflammasome activation and Bcl2 decline. The administration of NBTI, an inhibitor of ENT1, at a dose of 15 mg/kg, ameliorated neurologic deficits and morphologic lesions at both 24 and 72 h after SAH. Moreover, ENT1 inhibition efficiently mitigated neuronal degeneration and cell apoptosis. In addition, NBTI at 15 mg/kg observably increased Bcl2 content and decreased Bax level. Furthermore, suppression of ENT1 notably reduced the expression levels of NLRP3, apoptosis associated speck like protein containing CARD, caspase-1 and IL-1β.
NBTI relieved SAH-induced EBI partly through ENT1/NLRP3/Bcl2 pathway.
神经炎症和细胞凋亡是蛛网膜下腔出血（SAH）后早期脑损伤（EBI）的两个关键因素，与预后不良密切相关。最近，平衡核苷转运蛋白 1（ENT1）被发现可加速几种神经系统疾病（包括脑缺血、神经退行性变和癫痫）中的炎症和细胞凋亡的严重程度。然而，目前尚无研究阐述 ENT1 在 SAH 后 EBI 中的表达水平和作用。
采用血管内穿剌法制备 SAH 大鼠模型，SAH 后 0.5 h 经鼻给予硝基苄基硫代肌苷（NBTI）。采用 Western blot 检测 ENT1、NLRP3、Bcl2、Bax、ACS、Caspase-1、IL-1 的蛋白表达水平。采用改良 Garcia 评分和平衡木试验评估 SAH 后大鼠的神经功能。此外，采用苏木精-伊红、荧光素-J 和末端转移酶介导的 dUTP 缺口末端标记染色评估脑组织损伤和神经元凋亡。
分析表明，SAH 后 24 小时，内源性 ENT1 水平显著上调，同时 NLRP3 炎症小体激活和 Bcl2 下降。给予 ENT1 抑制剂 NBTI（剂量为 15 mg/kg）可改善 SAH 后 24 和 72 h 的神经功能缺损和形态学损伤。此外，ENT1 抑制可有效减轻神经元变性和细胞凋亡。此外，NBTI（15 mg/kg）可明显增加 Bcl2 含量，降低 Bax 水平。此外，抑制 ENT1 可显著降低 NLRP3、凋亡相关斑点样蛋白含 CARD、Caspase-1 和 IL-1β的表达水平。
NBTI 通过 ENT1/NLRP3/Bcl2 通路缓解 SAH 诱导的 EBI。
