Department of Anesthesiology, Nanchang Hongdu Hospital of Traditional Chinese Medicine, Nanchang, 330000, Jiangxi, People's Republic of China.
Department of Anesthesiology, The First Affiliated Hospital of Nanchang University, No.17, Yongwai Zhengjie, Donghu District, Nanchang, 330006, Jiangxi, People's Republic of China.
Neurochem Res. 2022 Jul;47(7):2064-2075. doi: 10.1007/s11064-022-03597-x. Epub 2022 May 10.
Ischemic stroke is a grievous intimidation to the healthiness of sufferers. Previous studies have reported that dexmedetomidine (DEX) has a protective effect on a variety of organs. This paper aimed to explore the regulatory mechanism of DEX in ischemic stroke through miR-665/ROCK2 axis. The mice model of ischemic stroke was constructed by middle cerebral artery occlusion (MCAO). The cell model of ischemic stroke was constructed by oxygen-glucose deprivation (OGD). Cell viability and apoptosis were assessed by CCK-8 assay and flow cytometry. The expression of cytokines was detected by ELISA. Lactate dehydrogenase (LDH) concentration was evaluated by LDH kit. The cerebral infarct volume of MCAO mice was detected by TTC staining, and the apoptosis of brain cells was detected by TUNEL staining. The target relationship between ROCK2 and miR-665 was analyzed by dual-luciferase reporter assay. DEX contributed cell viability from 42 to 66% (1 μM) and restrained cell apoptosis from 26 to 18% in HT22 cells treated with OGD (P < 0.01). Meanwhile, DEX decreased the expression of cytokines and LDH concentration from 184 to 126% (P < 0.001). Moreover, the expression of miR-665 enhanced 2.9 times (P < 0.05) and the expression of ROCK2 (P < 0.05) and NF-κB p65 (P < 0.01) reduced 1.8 times and 2.2 times after DEX treatment in OGD induced HT22. And miR-665 knockdown attenuated the effect of DEX on inflammation damage (the levels of TNF-α, IL-1β and IL-6 increased 1.36 times, 1.31 times, 1.43 time, respectively, and IL-10 decreased 1.68 times) and apoptosis from 17 to 25% (P < 0.01). MiR-665 directly targeted ROCK2 and regulated ROCK2 and NF-κB p65 expression (P < 0.01). Furthermore, ROCK2 overexpression inhibited the protective effect of DEX in HT22 induced by OGD (P < 0.001), while miR-665 overexpression reversed the regulatory of ROCK2 (P < 0.01). In vivo, DEX decreased cerebral infarction volume and inhibited apoptosis of brain cell (P < 0.001). DEX has a protective effect in ischemic stroke by promoting miR-665 expression to downregulate ROCK2/NF-κB axis, suggesting DEX has a beneficial effect on ischemic stroke and miR-665 is a conceivable target for the therapeutics and diagnosis of ischemic stroke.
缺血性脑卒中是对患者健康的严重威胁。先前的研究表明，右美托咪定（DEX）对多种器官具有保护作用。本文旨在通过 miR-665/ROCK2 轴探讨 DEX 对缺血性脑卒中的调控机制。通过大脑中动脉闭塞（MCAO）构建缺血性脑卒中小鼠模型，通过氧葡萄糖剥夺（OGD）构建缺血性脑卒中细胞模型。通过 CCK-8 测定和流式细胞术评估细胞活力和细胞凋亡。通过 ELISA 检测细胞因子的表达。通过 LDH 试剂盒评估乳酸脱氢酶（LDH）浓度。通过 TTC 染色检测 MCAO 小鼠脑梗死体积，通过 TUNEL 染色检测脑细胞凋亡。通过双荧光素酶报告实验分析 ROCK2 和 miR-665 的靶标关系。DEX 可将 OGD 处理的 HT22 细胞的细胞活力从 42%提高到 66%（1 μM），将细胞凋亡从 26%降低到 18%（P<0.01）。同时，DEX 将细胞因子和 LDH 浓度从 184%降低到 126%（P<0.001）。此外，DEX 处理后，OGD 诱导的 HT22 细胞中 miR-665 的表达增强了 2.9 倍（P<0.05），ROCK2（P<0.05）和 NF-κB p65（P<0.01）的表达降低了 1.8 倍和 2.2 倍。DEX 处理后，miR-665 敲低减弱了 DEX 对炎症损伤（TNF-α、IL-1β 和 IL-6 的水平分别增加了 1.36 倍、1.31 倍和 1.43 倍，而 IL-10 降低了 1.68 倍）和细胞凋亡（从 17%降低到 25%）的作用（P<0.01）。miR-665 直接靶向 ROCK2，并调节 ROCK2 和 NF-κB p65 的表达（P<0.01）。此外，ROCK2 过表达抑制了 OGD 诱导的 HT22 中 DEX 的保护作用（P<0.001），而过表达 miR-665 逆转了 ROCK2 的调节作用（P<0.01）。在体内，DEX 降低脑梗死体积并抑制脑细胞凋亡（P<0.001）。DEX 通过促进 miR-665 表达来下调 ROCK2/NF-κB 轴对缺血性脑卒中具有保护作用，表明 DEX 对缺血性脑卒中具有有益作用，miR-665 可能是缺血性脑卒中治疗和诊断的一个有前途的靶点。
