米诺环素对大鼠脑缺血半暗带脑血流量及内皮素-1蛋白表达的影响

目的：探讨米诺环素对大鼠脑缺血再灌注损伤后缺血半暗带脑血流量及内皮素-1（endothclin-1，ET-1）蛋白表达的影响。方法采用线栓法制作大鼠脑缺血再灌注损伤模型，将35只 SD 大鼠随机分为假手术组（n＝10）、模型组（n＝15）及米诺环素组（n＝15）。再灌注24 h 后，采用 Longa 法评估大鼠神经功能，激光多普勒血流仪监测大鼠脑缺血半暗带局部脑血流量，免疫组织化学法观察缺血侧皮质 ET-1蛋白的分布情况，再灌注6、24 h 时放射免疫法定量测定 ET-1蛋白的水平。结果同假手术组相比，模型组大鼠神经功能评分增加（P＜0．05）；缺血半暗带脑血流量明显减少（P ＜0．05），ET-1蛋白表达显著增加（P ＜0．05），米诺环素组较模型组大鼠神经功能评分明显降低（P＜0．05），脑缺血半暗带局部脑血流量增加（P＜0．05），ET-1蛋白的表达显著降低（P＜0．05）。结论米诺环素可增加大鼠脑缺血后局部脑血流量，抑制 ET-1蛋白的表达，减轻大鼠神经功能损害，从而发挥神经保护作用。

Effects of minocycline on cerebral blood flow and endothelin-1 protein expression in ischemic penumbra of rats with focal cerebral ischemia reperfusion

Objective To investigate the effects of minocycline on regional cerebral blood flow and the expression of endothe-lin-1(ET-1) in ischemic penumbra of rats after focal cerebral ischemia reperfusion injury .Methods Middle cerebral artery occlusion (MCAO) with nylon suture was used to be established as focal cerebral ischemia reperfusion mode (I/R) ,a total of 35 male Spra-geue-Dawley rats were randomly divided into 3 groups :sham-operated group(n= 10) ,model group(n= 15) and minocycline group (n= 15) .After 24 hours of I/R ,The neurobehavioral function of rats was evaluated by Longa′s test ,the regional cerebral blood flow in ischemic penumbra was assessed with laser-Doppler flowmetry .After 6 and 24 hours of I/R ,the expression of ET-1 in peri-in-farct region was measured by both immunohistochemistry and radioimmunoassay .Results Compared with sham-group ,the Longa′s test scales ,ET-1 protein expression increased and the rCBF decreased in ischemic penumbra in model group(P< 0 .05) .the Longa′s test scales ,ET-1 protein expression decreased and the rCBF decreased in ischemic penumbra in minocycline group when compared to the model group(P< 0 .05) .Conclusion Minocycline could promote neurological functional recovery of rats after MCAO ,which might be attributed to increase the cerebral blood flow and regulate the endothelin-1 expression in ischemic penumbra .