Induction of secretory phospholipase A2 in reactive astrocytes in response to transient focal cerebral ischemia in the rat brain
Induction of secretory phospholipase A2 in reactive astrocytes in response to transient focal cerebral ischemia in the rat brain
复制标题
DOI：
10.1111/j.1471-4159.2004.02540.x
复制
发表时间：
2004-08-01
影响因子：
4.7
通讯作者：
Sun, GY
中科院分区：
文献类型：
--
作者：
Lin, TN;Wang, Q;Sun, GY
尽管IIA族分泌型磷脂酶A（2）（sPLA（2）-IIA）的mRNA表达与CNS损伤反应有关，但关于蛋白质表达的信息仍不清楚。在本研究中，我们研究了大脑中动脉阻塞诱导的大鼠短暂局灶性脑缺血中sPLA（2）-IIA mRNA和免疫反应性的时空表达。北方印迹分析显示，缺血再灌注60分钟后sPLA（2）-IIA mRNA表达呈双相增加：30分钟时出现早期阶段，12 h至14 d的晚期阶段出现第二次增加。原位杂交显示sPLA（2）-IIA mRNA早期增加位于受影响的缺血皮质，晚期增加位于半影区。除sPLA（2）-IIA mRNA外，胶质细胞酸性蛋白（GFAP）和环氧合酶-2 mRNA在缺血再灌注后3天也显示半暗带面积增加，但胞浆PLA（2）没有增加。sPLA（2）-IIA免疫组织化学染色显示半暗带区的阳性细胞类似于GFAP阳性的星形胶质细胞，但不同于isolectin B4阳性的小胶质细胞。共聚焦显微镜进一步证实了sPLA（2）-IIA在反应性星形胶质细胞中的免疫反应性，但在小胶质细胞中没有。综上所述，这些结果首次证明了在反应性星形胶质细胞中炎症性sPLA（2）-IIA对脑缺血-再灌注的反应性上调。
Although mRNA expression of group IIA secretory phospholipase A(2) (sPLA(2)-IIA) has been implicated in responses to injury in the CNS, information on protein expression remains unclear. In this study, we investigated temporal and spatial expression of sPLA(2)-IIA mRNA and immunoreactivity in transient focal cerebral ischemia induced in rats by occlusion of the middle cerebral artery. Northern blot analysis showed a biphasic increase in sPLA(2)-IIA mRNA expression following 60-min of ischemia-reperfusion: an early phase at 30 min and a second increase at a late phase ranging from 12 h to 14 days. In situ hybridization localized the early-phase increase in sPLA(2)-IIA mRNA to the affected ischemic cortex and the late-phase increase to the penumbral area. Besides sPLA(2)-IIA mRNA, glial fibrillary acidic protein (GFAP) and cyclo-oxygenase-2 mRNAs, but not cytosolic PLA(2), also showed an increase in the penumbral area at 3 days after ischemia-reperfusion. Immunohistochemistry of sPLA(2)-IIA indicated positive cells in the penumbral area similar to the GFAP-positive astrocytes but different from the isolectin B4-positive microglial cells. Confocal microscopy further confirmed immunoreactivity of sPLA(2)-IIA in reactive astrocytes but not in microglial cells. Taken together, these results demonstrate for the first time an up-regulation of the inflammatory sPLA(2)-IIA in reactive astrocytes in response to cerebral ischemia-reperfusion.