米诺环素对缺血性脑卒中血脑屏障重塑的影响及其机制

目的探索米诺环素（minocycline，MC）对大鼠局限性脑缺血再灌注后血脑屏障（blood-brain barrier，BBB）重塑及神经保护的作用机制及影像可视化。方法48只SD大鼠随机分为4组：早期给药组、晚期给药组、生理盐水组及假手术组，每组12只。其中早期给药组于手术后即刻尾静脉注入MC（3 mg/kg）；晚期给药组于拔线后恢复再灌注6 h后大鼠尾静脉注入MC（3 mg/kg）；生理盐水组于再灌注即刻注入相同体积的生理盐水；假手术组除了不插入线栓外，其余处理同生理盐水组。再灌注24 h后进行神经功能评分，并采用HE、免疫组化、Western blot、免疫荧光及磁共振成像等方法观察MC对脑缺血再灌注后BBB重塑的影响及影像学改变。结果缺血再灌注24 h后各组神经功能缺损评分差异有统计学意义（P<0.001），其中生理盐水组神经功能缺损评分高于给药组；早期给药组神经功能缺损评分低于晚期给药组。磁共振图像显示各组最终梗死体积差异有统计学意义（P<0.001）。早期给药组及晚期给药组梗死体积显著小于生理盐水组，早期给药组小于晚期给药组，假手术组未显示梗死灶。给药组脑组织中肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-1β、CD11b的表达低于生理盐水组，且早期给药组低于晚期给药组；给药组脑组织中转化生长因子-β(TGF-β)、IL-10、YM1、RECA-1、PDGFR-β的表达高于生理盐水组，且早期给药组高于晚期给药组。给药组血清中IL-1β、IL-6和TNF-α含量低于生理盐水组，且早期给药组低于晚期给药组。Western blot结果显示给药组IL-1β、基质金属蛋白酶-3(MMP-3)、TNF-α的表达低于生理盐水组，且早期给药组低于晚期给药组；给药组claudin-5、occludin、ZO-1、IL-10、TGF-β和YM1的表达高于生理盐水组，且早期给药组高于晚期给药组。结论MC可有效减轻缺血再灌注损伤促发BBB重塑，立即给药对神经功能障碍的改善作用更明显。

Effect of minocycline on remodeling of blood-brain barrier in ischemic stroke and its mechanism

ObjectiveTo investigate the effect of minocycline (MC) on remodeling and protecting of the blood-brain barrier (BBB) in focal cerebral ischemia-reperfusion and its mechanism in rats. Methods Forty-eight SD rats were randomly divided into 4 groups, early administration group, late administration group, saline group, and sham operation group. The effect of MC on BBB remodeling after cerebral ischemia-reperfusion and MR images changes were observed by HE, immunohistochemistry, Western blotting, immunofluorescence and magnetic resonance imaging. And neurological function scores were evaluated after 24 hours of reperfusion. ResultsThere was a significant difference in the neurological deficit score among the three reperfusion groups 24 hours after ischemia-reperfusion (P<0.001); in which the neurological deficit score in the saline group was higher than the administration group. The neurological deficit score in the early administration group was lower than that in the late administration group. Magnetic resonance images showed that there was a significant difference in the final infarct volume among the three groups (P<0.001). The infarct volume of the early administration group and late administration group was significantly smaller than that of the saline control group; and that of the early administration group was smaller than that of the late administration group. There was no infarct in the sham operation group. The expressions of TNF-α, IL-1 β and CD11b in the brain tissues of the treatment group were lower than those of the saline group; and those of the early administration group were lower than those of the late administration group. The expressions of TGF-β, IL-10, YM1, RECA-1 and PDGFR-β in the brain tissues of the treatment group were higher than those of the saline group; and those of the early administration group were higher than those of the late administration group. The contents of serum IL-1 β, IL-6 and TNF-α in the treatment group were lower than those in the saline group; and those in the early administration group were lower than those in the late administration group. The results of Western blot showed that the expressions of IL-1β, MMP-3 and TNF-α in the treatment group were lower than those in the saline group; and those in the early administration group were lower than those in the late administration group. While the expressions of claudin-5, occludin, ZO-1, IL-10, TGF-β and YM1 in the administration group were higher than those in the saline group; and the expression in the early administration group were higher than those in the late administration group. ConclusionMC can effectively alleviate ischemia-reperfusion injury and promote BBB remodeling, and immediate administration can improve the improvement of neurological dysfunction.