Department of Internal Medicine, Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Mich. 48109, USA.
Stroke. 2011 Jan;42(1):179-85. doi: 10.1161/STROKEAHA.110.598441. Epub 2010 Nov 24.
mineralocorticoid receptor (MR) antagonists have protective effects in rodent models of ischemic stroke, but the cell type-specific actions of these drugs are unknown. In the present study, we examined the contribution of myeloid cell MR during focal cerebral ischemia using myeloid-specific MR knockout mice.
myeloid-specific MR knockout mice were subjected to transient (90 minutes) middle cerebral artery occlusion followed by 24 hours reperfusion (n=5 to 7 per group). Ischemic cerebral infarcts were identified by hematoxylin and eosin staining and quantified with image analysis software. Immunohistochemical localization of microglia and macrophages was performed using Iba1 staining, and the expression of inflammatory markers was measured after 24 hours of reperfusion by quantitative reverse transcription-polymerase chain reaction.
myeloid-specific MR knockout resulted in a 65% reduction in infarct volume (P=0.005) after middle cerebral artery occlusion. This was accompanied by a significant reduction in activated microglia and macrophages in the ischemic core. Furthermore, myeloid-specific MR knockout suppressed classically activated M1 macrophage markers tumor necrosis factor-α, interleukin-1β, monocyte chemoattractant protein-1, macrophage inflammatory protein-1α, and interleukin-6 at the same time as partially preserving the induction of alternatively activated, M2, markers Arg1, and Ym1.
these data demonstrate that myeloid MR activation exacerbates stroke and identify myeloid MR as a critical target for MR antagonists. Furthermore, these data indicate that MR activation has an important role in controlling immune cell function during the inflammatory response to stroke.
醛固酮受体（MR）拮抗剂在缺血性卒中的啮齿动物模型中具有保护作用，但这些药物的细胞类型特异性作用尚不清楚。在本研究中，我们使用髓系特异性 MR 敲除小鼠研究了局灶性脑缺血过程中髓系细胞 MR 的作用。
对髓系特异性 MR 敲除小鼠进行短暂（90 分钟）大脑中动脉闭塞，随后再灌注 24 小时（每组 5 至 7 只）。通过苏木精和伊红染色鉴定缺血性脑梗死，并通过图像分析软件进行定量。使用 Iba1 染色进行小胶质细胞和巨噬细胞的免疫组织化学定位，并用定量逆转录聚合酶链反应测量再灌注 24 小时后的炎症标志物表达。
髓系特异性 MR 敲除小鼠大脑中动脉闭塞后梗死体积减少 65%（P=0.005）。这伴随着缺血核心中激活的小胶质细胞和巨噬细胞的显著减少。此外，髓系特异性 MR 敲除同时抑制了经典激活的 M1 巨噬细胞标志物肿瘤坏死因子-α、白细胞介素-1β、单核细胞趋化蛋白-1、巨噬细胞炎性蛋白-1α和白细胞介素-6，同时部分保留了替代激活的 M2 标志物 Arg1 和 Ym1 的诱导。
这些数据表明髓系 MR 激活加剧了卒中，并确定髓系 MR 是 MR 拮抗剂的一个关键靶点。此外，这些数据表明，MR 激活在控制卒中炎症反应中免疫细胞功能方面具有重要作用。
