缺血后适应抑制大鼠脑缺血-再灌注后星形胶质细胞的增生

目的：观察缺血后适应（ ischemia postconditioning,IPostC）对大鼠脑缺血-再灌注损伤后胶质纤维酸性蛋白（ glial fibrillary acidic protein,GFAP）和组蛋白去乙酰化酶1（histone deacetylase1,HDAC1）表达变化,初步探讨 IPostC 对星形胶质细胞增生的影响。方法采用线栓法制备大鼠短暂性大脑中动脉阻塞模型（transient middle cerebral occlusion,tMCAO）模型,采用抽签法将21只健康雄性 Sprague Dawley（SD）大鼠（体质量280~300 g）随机分为7组,每组3只：①假手术组（S）；② tMCAO 1h 组（R-1h）；③ tMCAO＋IPostC 1h 组（P-1h）；④ tMCAO 4h 组（R-4h）；⑤ tMCAO＋IPostC 4h 组（P-4h）；⑥ tMCAO 24h 组（R-24h）；⑦tMCAO＋IPostC 24h 组（P-24h）。缺血后适应的具体操作是在拔除线栓后即刻用动脉阻断夹夹闭双侧颈总动脉,阻断血流10 s后恢复血流10 s,如此反复操作5次。分别应用 Western blotting 法和免疫荧光法研究大鼠脑缺血-再灌注及后适应1、4和24 h 时HDAC1和 GFAP 表达的变化。结果（1）Western blotting 结果显示：①与 S 组相比,R 组 GFAP 蛋白的表达均有所增加,R-1h 和R-24h 显著增加（P〈0.05）,P 组的表达变化不大。与 R 组相比,P 组 GFAP 的表达下降,其中 P-4h 组显著下降（P〈0.05）。②与 S组相比,R 组 HDAC1蛋白的表达均有所增加,其中 R-1h 显著增加（P〈0.05）,P 组的表达变化不大。与 R 组相比,P 组 HDAC1的表达下降。（2）免疫荧光结果显示：HDAC1和 GFAP 蛋白有共定位,且 HDAC1和 GFAP 的变化趋势同 Western blotting 结果相同。结论 IPostC 可能通过降低 HDAC1的表达来抑制星形胶质细胞的增生从而发挥对脑缺血-再灌注损伤的神经保护作用。

Ischemic postconditioning inhibited the proliferation of astrocyte following cerebral ischemia-reperfusion in rats

Objective To observe the effect of ischemic postconditioning（ IPostC） on histone deacetylase 1 （ HDAC1） and glial fibrillary acidic protein（GFAP） expression induced by cerebral ischemia-reperfusion injury in rats, and preliminarily explore the effect of IPostC on proliferation of astrocyte. Methods Transient middle cerebral occlusion（tMCAO） operation was performed by using suture method. A total of 21 male Sprague-Dawley（SD） rats（280-300 g） were randomly divided into 7 groups： ① Sham group（S）; ② tMCAO 1 h group（R-1h）; ③ tMCAO＋IPostC 1 h group（P-1h）; ④ tMCAO 4 h group（R-4h）; ⑤ tMCAO＋IPostC 4 h group（P-4h）; ⑥ tMCAO 24 h group（R-24h）; ⑦ tMCAO＋IPostC 24 h group（P-24h）. In the tMCAO＋IPostC groups, IPostC was carried out by five cycles of 10 s occlusion/ 10 s release of the bilateral common carotid arteries using clamps immediately after reperfusion. Western blotting and immunofluorescence staining were used to observe the expression levels of HDAC1 and GFAP. Results Western blotting results showed that compared with the S group, the GFAP protein expression was increased in R groups and those in the R-1h and R-24h groups were statistically significantly increased（P〈0. 05）. The GFAP protein expression in P groups did not change significantly. Compared with the R group, the GFAP protein expression was reduced in P groups and that in the P-4h group was statistically significantly reduced（P〈0. 05）. Compared with the S group, the HDAC1 protein expression was increased in R groups and that in the R-1h group was statistically significantly increased（P〈0. 05）. The HDAC1 protein expression in P groups did not change significantly. Compared with the R group, the HDAC1 protein expression in P groups was reduced clearly. The immunofluorescence staining results showed that HDAC1 was colocated with GFAP, and also were consistent with those of the Western blotting. Conclusion IPostC decreased the proliferation of astrocyte probably through decreasing HDAD1, therefore, to play a protective role in the ischemia-reperfusion injured brain.