脑缺血大鼠脑内AT1和AT2受体表达的免疫组化观察

目的 观察成体大鼠脑缺血后脑内是否重新表达血管紧张素Ⅱ受体（AT1和AT2受体）,探讨AT1和AT2受体表达变化与脑缺血的关系.方法 采用微创开颅法复制大鼠大脑中动脉闭塞（MCAO）模型,将25只成年雄性SD大鼠分为正常对照组（n=5）,假手术组（n=5）和缺血组（随机分为缺血后1d、3d和1周3组,每组n=5）.用抗AT1和抗AT2抗体分别进行免疫组织化学染色.结果 MCAO后在缺血半暗区内可见大量AT1和AT2受体免疫阳性表达的细胞,分别以缺血后3d和1周数目最多,且免疫阳性反应最强,与对照组相比有显著性差异（P＜0.05）.结论 脑缺血后大鼠脑内能重新表达AT1和AT2受体,通过血管紧张素Ⅱ（AngⅡ）的介导,参与脑缺血的病理过程.

Immunohistochemical Study of AT1 and AT2 Receptors Expression in Cerebral Ischemia at Rats

Objective To study the expression of AT1 and AT2 receptors following the focal cerebral ischemia in the rats.Methods The rat model of middle cerebral artery occlusion （MCAO） was established by minimal invasive craniotomy.The twenty-five SD adult male rats were randomly divided into normal control groups （n=5）,sham operation groups （n=5）,cerebral ischemia groups （including 1 d,3 d,1 w groups after MCAO,n =5）.Immunohistochemistry was used to observe the expression of AT1 and AT2 receptors by anti-AT1 and anti-AT2 antibodies.Results There were a large number of AT1 and AT2 receptors-positive cells in the ischemia border （penumbra） zone.These cells respectively reached the peak in 3 d and 1 w post-injury with the largest number,and the optical density of the AT1 and AT2-positive cells increased strikingly,which showed significantly differences compared with the control groups （P＜0.05）.Conclusion The adult brain can express AT1 and AT2 receptors after cerebral ischemia as in the developing brain,which may be an important cell source of angiotensin-receptor system involving the pathological processes of ischemia.