Yang G Y, Liu X H, Kadoya C, Zhao Y J, Mao Y, Davidson B L, Betz A L
Department of Surgery (Neurosurgery), University of Michigan, Ann Arbor 48109-0532, USA.
J Cereb Blood Flow Metab. 1998 Aug;18(8):840-7. doi: 10.1097/00004647-199808000-00004.
It has been demonstrated that administration of an interleukin-1 receptor antagonist protein (IL-1ra) reduces ischemic brain injury; however, the detrimental mechanism initiated by interleukin-1 (IL-1) in ischemic brain injury is unclear. In this study, we used mice that were transfected to overexpress human IL-1ra to elucidate the role of IL-1 in the activation of the inflammatory response after middle cerebral artery occlusion (MCAO). Myeloperoxidase (MPO) activity and immunohistostaining were used as a marker of polymorphonuclear leukocytes (PMNL) infiltration. Adenoviral vector (1 x 10(9) particles) was administered by injection into the right lateral ventricle in mice. Five days later, MCAO was performed on the mice using a suture technique. Permanent MCAO was achieved for 24 hours in the Ad.RSVIL-1ra-transfected. Ad.RSVlacZ-transfected, and saline (control) mice. Myeloperoxidase activity was quantified in each region and localization of MPO was determined by immunohistochemistry. After 2 hours of MCAO, the surface cerebral blood flow was reduced to 13.5% +/- 3.4%, 10.75% +/- 2.6%, and 10.9% +/- 2.6% of baseline in the ischemic hemisphere in Ad.RSVIL-1ra-transfected, Ad.RSVlacZ-transfected, and saline-treated mice, respectively. The MPO activity in the ischemic hemisphere in the Ad.RSVlacZ group was similar to that in the saline control group (cortex: 0.40 +/- 0.22 versus 0.33 +/- 0.11; basal ganglia: 0.46 +/- 0.23 versus 0.49 +/- 0.17; P > 0.05); however, it was significantly reduced in the Ad.RSVIL-1ra group (cortex: 0.18 +/- 0.07; basal ganglia: 0.26 +/- 0.15; P < 0.05). Myeloperoxidase immunohistochemistry showed that the massive accumulation of MPO-positive cells in the ischemic cortex, striatum, and corpus callosum regions was greatly attenuated in Ad.RSVIL-1ra-transfected mice. Our results indicate that Ad.RSVIL-1ra-transfected mice provide a useful tool to study the mechanism of action of IL-1. The MPO activity assay and immunostaining after 24 hours of focal ischemia were significantly reduced in IL-1ra gene-transfected mice, suggesting that IL-1 may play an important role in the activation of inflammatory cells during focal cerebral ischemia.
已经证明，给予白细胞介素-1受体拮抗剂蛋白（IL-1ra）可减少缺血性脑损伤；然而，白细胞介素-1（IL-1）在缺血性脑损伤中引发的有害机制尚不清楚。在本研究中，我们使用转染以过表达人IL-1ra的小鼠来阐明IL-1在大脑中动脉闭塞（MCAO）后炎症反应激活中的作用。髓过氧化物酶（MPO）活性和免疫组织化学染色被用作多形核白细胞（PMNL）浸润的标志物。通过注射将腺病毒载体（1×10⁹个颗粒）注入小鼠右侧脑室。五天后，使用缝合技术对小鼠进行MCAO。在Ad.RSVIL-1ra转染、Ad.RSVlacZ转染和生理盐水（对照）小鼠中实现永久性MCAO 24小时。对每个区域的髓过氧化物酶活性进行定量，并通过免疫组织化学确定MPO的定位。MCAO 2小时后，Ad.RSVIL-1ra转染、Ad.RSVlacZ转染和生理盐水处理的小鼠缺血半球的表面脑血流量分别降至基线的13.5%±3.4%、10.75%±2.6%和10.9%±2.6%。Ad.RSVlacZ组缺血半球的MPO活性与生理盐水对照组相似（皮质：0.40±0.22对0.33±0.11；基底神经节：0.46±0.23对0.49±0.17；P>0.05）；然而，Ad.RSVIL-1ra组的MPO活性显著降低（皮质：0.18±0.07；基底神经节：0.26±0.15；P<0.05）。髓过氧化物酶免疫组织化学显示，在Ad.RSVIL-1ra转染的小鼠中，缺血皮质、纹状体和胼胝体区域中MPO阳性细胞的大量积累大大减弱。我们的结果表明，Ad.RSVIL-1ra转染的小鼠为研究IL-1的作用机制提供了一个有用的工具。局灶性缺血24小时后的MPO活性测定和免疫染色在IL-1ra基因转染的小鼠中显著降低，表明IL-1可能在局灶性脑缺血期间炎症细胞的激活中起重要作用。
