中性粒细胞明胶酶相关载脂蛋白在大鼠脑出血后继发性脑损伤中的作用研究

Role of neutrophil gelatinase-associated lipocalin in secondary brain injury after intracerebral hemorrhage in rats

摘要:

目的 探讨中性粒细胞明胶酶相关载脂蛋白（NGAL）在脑出血（ICH）后继发性脑损伤中的作用。方法 采用Ⅶ胶原酶制作ICH模型，将90只雄性SD大鼠随机分为3组:正常对照组（10只）、假手术组（40只）和ICH模型组（40只）。分别在ICH后6 h、24 h、72 h和7 d四个时间点对大鼠进行神经功能缺损评分；用免疫组化及RT-qPCR来观察不同时间点脑组织NGAL及MMP-9表达情况。结果 免疫组化及RT-qPCR结果显示ICH后模型组各时间点均可见大量NGAL、MMP-9阳性细胞及NGAL mRNA表达，且明显高于正常组及假手术组（P<0.05）。ICH模型组NGAL与MMP-9蛋白表达呈正相关（P<0.01）。ICH模型组NGAL、MMP-9蛋白表达均与大鼠神经功能缺损评分呈正相关（P<0.05）。结论 ICH后NGAL表达明显增加，提示NGAL可能参与了脑出血后继发性脑损伤，并可能通过调节MMP-9的活性从而发挥作用，但NGAL是否为MMP-9的上游调控因子尚有待进一步研究。

Abstract:

Objective To investigate the role of neutrophil gelatinase-associated lipocalin (NGAL) in secondary brain injury after intracerebral hemorrhage (ICH).Methods Type VII collagenase was used to establish the model of ICH. A total of 90 male Sprague-Dawley rats were randomly divided into normal control group (10 rats), sham-operation group (40 rats), and ICH model group (40 rats). The neurologic impairment score was obtained at 6, 24, and 72 hours and 7 days after ICH, and immunohistochemistry and RT-qPCR were used to measure the expression of NGAL and matrix metallopeptidase-9 (MMP-9) in brain tissue at different time points.Results The results of immunohistochemistry and RT-qPCR showed that the model group had a large number of cells with the expression of NGAL and MMP-9, as well as the mRNA expression of NGAL, which were significantly higher than those of the normal control group and sham-operation group (P<0.05). In the ICH model group, the protein expression of NGAL was positively correlated with that of MMP-9 (P<0.01), and the protein expression of NGAL and MMP-9 was also positively correlated with neurologic impairment score in rats (P<0.05).Conclusions There is increased expression of NGAL after ICH, which suggests that NGAL may be involved in secondary brain injury after ICH. NGAL may regulate the activity of MMP-9, but further studies are needed to determine whether NGAL is the upstream regulatory factor of MMP-9.