Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450000, China.
Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450000, China.
Exp Neurol. 2021 May;339:113645. doi: 10.1016/j.expneurol.2021.113645. Epub 2021 Feb 15.
Microglia are rapidly activated after acute ischemic stroke, and the polarization of microglial is associated with the prognosis of acute ischemic stroke. Lipoxin A4 (LXA4), an anti-inflammatory agent, has a protective effect against ischemic stroke. However, the role of LXA4 on the polarization of microglial after acute ischemic stroke remains undetermined. We hypothesized that LXA4 may exert the neuroprotective effect though regulating the polarization of microglial. In this study, clinical features of acute ischemic stroke were simulated using a rat model of model of middle cerebral artery occlusion (MCAO) in vivo and the BV2 microglia oxygen-glucose deprivation/reoxygenation model (OGD/R) in vitro. The protective effects of LXA4 on cerebral ischemia-reperfusion injury were determined using TTC staining, HE staining, and TUNEL staining. The expression of targeted genes was assayed using quantitative real-time PCR (qRT-PCR), immunofluorescence, and western blot to investigated the regulation of LXA4 on microglia polarization after acute ischemic stroke. We found that LXA4 exerted protective effects on focal cerebral ischemia-reperfusion injury and reduced the expression of the pro-inflammatory cytokines IL-1β and TNF-α. Furthermore, LXA4 inhibited the expression of Notch-1, Hes1, iNOS and CD32 all of which are associated with the differentiation into M1 microglia. By contrast, LXA4 upregulated the expression of Hes5, Arg-1 and CD206 all of which are associated with M2 phenotype in microglia. In addition, blocking the Notch signaling pathway with the inhibitor DAPT significantly mitigated the effect of LXA4 on microglia differentiation. These data suggest that LXA4 may regulate the polarization of microglia after cerebral ischemia-reperfusion injury through the Notch signaling pathway.
小胶质细胞在急性缺血性卒中后迅速被激活，小胶质细胞的极化与急性缺血性卒中的预后相关。脂氧素 A4（LXA4）作为一种抗炎剂，对缺血性卒中具有保护作用。然而，LXA4 对急性缺血性卒中后小胶质细胞极化的作用尚不确定。我们假设 LXA4 可能通过调节小胶质细胞的极化发挥神经保护作用。在这项研究中，我们使用体内大脑中动脉阻塞（MCAO）模型和体外 BV2 小胶质细胞氧葡萄糖剥夺/复氧（OGD/R）模型模拟急性缺血性卒中的临床特征。通过 TTC 染色、HE 染色和 TUNEL 染色来确定 LXA4 对脑缺血再灌注损伤的保护作用。通过定量实时 PCR（qRT-PCR）、免疫荧光和 Western blot 来检测 LXA4 对急性缺血性卒中后小胶质细胞极化的调节作用，以检测靶向基因的表达。结果发现，LXA4 对局灶性脑缺血再灌注损伤具有保护作用，并降低了促炎细胞因子 IL-1β和 TNF-α的表达。此外，LXA4 抑制了 Notch-1、Hes1、iNOS 和 CD32 的表达，这些基因都与 M1 型小胶质细胞分化有关。相比之下，LXA4 上调了 Hes5、Arg-1 和 CD206 的表达，这些基因都与小胶质细胞中的 M2 表型有关。此外，用抑制剂 DAPT 阻断 Notch 信号通路可显著减轻 LXA4 对小胶质细胞分化的影响。这些数据表明，LXA4 可能通过 Notch 信号通路调节脑缺血再灌注损伤后小胶质细胞的极化。
