慢性局灶脑缺血区小胶质细胞/巨噬细胞呈持续性反应

目的:观察小胶质细胞/巨噬细胞对慢性局灶脑缺血的反应。方法:运用局灶脑缺血模型和免疫组织化学染色方法对36只成年雄性SD大鼠的大脑皮质缺血区和尾壳核区的ED1和OX42阳性细胞的反应时程、分布形式和细胞形态变化进行了探查。结果:在脑缺血3d,ED1阳性细胞呈圆形,大多数分布于大脑皮质缺血区周围和缺血侧的尾壳核,仅有少量ED1阳性细胞位于缺血区中央。阳性细胞明显多于对照组。脑缺血2周,ED1阳性细胞数量最多,主要分布于大脑皮质缺血区中央和尾壳核外侧部。脑缺血6周,其数量稍有下降,细胞形态无明显变化。脑缺血3d时,OX42阳性细胞呈"星状",胞体肥大,数量增加,分布于皮质缺血区的外周和尾壳核。缺血中央区的阳性细胞数量少。脑缺血2周,OX42阳性细胞胞体明显增大,分支增粗。在大脑皮质缺血区中央出现大量圆形的没有明显突起的OX42阳性细胞。此时,尾壳核外侧部的阳性细胞的数量和胞体明显增加。脑缺血6周,阳性细胞的数量稍有下降。结论:小胶质细胞/巨噬细胞对局灶脑缺血发生持续性的反应,此可能与迟发性神经元损伤和脑缺血区的自我修复有关。

Persistent response of microglia/macrophages following chronic focal cerebral ischemia in rats

AIM: To study the microglial/macrophagic reactions to chronic foral cerebral ischmeia METHODS:ED1 and OX42 positive cellular reactive profiles including time-course and distribution as well as morphological changes were explored in the ischemic cortex and the ischemic caudoputamen of 36 SD adult rats by using focal cerebral ischemic model and immunohistochemical method RESULTS: On the 3rd day after ischemia, an increased number of round ED1 positive cells were found in the outer boundary of cortical ischemic foci and the ischemic caudoputamen, and some of the positive cells were present in the cortical ischemic core At 2nd week after ischemia, ED1 positive cells peaked in number, and they were located at cortical ischemic core and lateral caudoputamen, at which they persisted up to 6 weeks after ischemia. On the 3rd day after ischemia, ramified OX42 positive cells became hypertrophy and a marked increase in number, and they were present at the periphery of ischemic foci and in the ischemic caudoputamen At 2nd week after ischemia, OX42 positive cells became more hypertrophy, and a number of round OX42 positive cells were detected in the cortical ischemic core, in which they persisted up to 6 weeks after ischemia. CONCLUSION:Focal cerebral ischemia induces microglial/macrophagic reaction persistently, which may be correlative with neuronal delayed injury and self recovery of ischemic foci.