Li Zhihua, Chen Xi, Zhang Xiaoyang, Ren Xiuhua, Chen Xuemei, Cao Jing, Zang Weidong, Liu Xianzhi, Guo Fuyou
Department of Human Anatomy, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China.
Department of Neurosurgery, The First Affiliated Hospital of Zhengzhou University, No. 1 the Jianshe East Road, Zhengzhou, Henan Province, 450052, People's Republic of China.
J Mol Neurosci. 2017 Feb;61(2):279-288. doi: 10.1007/s12031-017-0883-3. Epub 2017 Jan 17.
Excessive Dickkopf-1 (Dkk-1) plays a vital role in secondary brain injury following ischemic stroke and psychotic disease. However, it is unclear whether an increased expression of Dkk-1 occurred after intracerebral hemorrhage (ICH). The present study examined the potential role of Dkk-1 after ICH. ICH was induced by a single injection of autologous blood into the basal ganglia of rats. Dkk-1 protein levels in brain tissue and serum were detected by enzyme-linked immunosorbent assay after ICH. Rats were treated with small interfering RNA targeting Dkk-1 (siDkk-1) or vehicle following ICH. Behavioral deficits and brain water content were examined. Blood-brain barrier (BBB) integrity was detected by Evans blue extravasation and observed by transmission electron microscopy. Wnt-1 was evaluated by real-time RT-PCR. The tight junction protein zonula occludens-1 (ZO-1) was investigated by immunohistochemistry and Western blot assays. Serum level of Dkk-1 did not differ between the ICH and sham groups. However, the level of Dkk-1 in brain tissue was significantly increased at 24 and 72 h after ICH. BBB disruption and brain edema, as well as neurological deficits, were remarkably ameliorated by administration of siDkk-1. Moreover, siDkk-1 treatment significantly increased the transcription of Wnt-1 mRNA and upregulated the expression of ZO-1. These results provide the first evidence that siDkk-1 treatment is neuroprotective against secondary injury including brain edema and BBB permeability following ICH; the mechanism of neuroprotection may be associated with improvement of BBB integrity.
过量的Dickkopf-1（Dkk-1）在缺血性中风和精神疾病后的继发性脑损伤中起重要作用。然而，脑出血（ICH）后Dkk-1表达是否增加尚不清楚。本研究探讨了ICH后Dkk-1的潜在作用。通过向大鼠基底神经节单次注射自体血诱导ICH。ICH后通过酶联免疫吸附测定法检测脑组织和血清中的Dkk-1蛋白水平。ICH后用靶向Dkk-1的小干扰RNA（siDkk-1）或载体处理大鼠。检测行为缺陷和脑含水量。通过伊文思蓝外渗检测血脑屏障（BBB）完整性，并通过透射电子显微镜观察。通过实时RT-PCR评估Wnt-1。通过免疫组织化学和蛋白质印迹分析研究紧密连接蛋白闭合蛋白-1（ZO-1）。ICH组和假手术组之间血清Dkk-1水平无差异。然而，ICH后24小时和72小时脑组织中Dkk-1水平显著升高。给予siDkk-1可显著改善BBB破坏、脑水肿以及神经功能缺损。此外，siDkk-1治疗显著增加Wnt-1 mRNA的转录并上调ZO-1的表达。这些结果提供了首个证据，即siDkk-1治疗对ICH后的继发性损伤具有神经保护作用，包括脑水肿和BBB通透性；神经保护机制可能与改善BBB完整性有关。
