围产期缺氧缺血性脑病大鼠模型中氯化钴的预处理及治疗后处理

Preconditioning and post-treatment with cobalt chloride in rat model of perinatal hypoxic-ischemic encephalopathy.

作者信息

Dai Ying, Li Wendi, Zhong Min, Chen Jie, Liu Youxue, Cheng Qian, Li Tingyu

机构信息

Department of Primary Child Health Care, Children's Hospital of Chongqing Medical University, PR China.

Children's Nutritional Research Center, Key Laboratory of Developmental Diseases in Childhood of Education Ministry, Key Laboratory of Pediatrics in Chongqing, CSTC2009CA5002, Chongqing International Science and Technology Cooperation Center for Child Development and Disorder, Children's Hospital of Chongqing Medical University, PR China.

出版信息

Brain Dev. 2014 Mar;36(3):228-40. doi: 10.1016/j.braindev.2013.04.007. Epub 2013 May 18.

DOI:10.1016/j.braindev.2013.04.007

PMID:23694759

Abstract

BACKGROUND

Hypoxia-ischemia (HI)-induced perinatal encephalopathy is a major cause of acute mortality and chronic neurologic morbidities such as cerebral palsy, mental retardation, and epilepsy. As the essential transcription factor for the activation of hypoxia-inducible genes, hypoxia-inducible factor 1 alpha (HIF-1α) plays an important role in the pathophysiological response to the stress of HI brain damage. Whether HIF-1α activation promotes neuroprotection in HI tissues is controversial.

METHODS

The left common carotid artery of rats aged 7days was ligated under anesthesia. The pups were then exposed to hypoxia in a normobaric chamber filled with 8% oxygen and 92% nitrogen for 2.5h. In the sham control group, the left common carotid artery was exposed but was not ligated or exposed to hypoxia. To assess the time window for effective treatment, the HIF-1α inducer cobalt chloride (CoCl2) was injected subcutaneously 1day before surgery, immediately or 1day after surgery. The brain tissues were harvested from the pups of each groups at 1, 2 and 7days after insult for HIF-1α protein ant its target genes expression and for investigating the injury. Morris water maze tests were performed at postnatal 7weeks.

RESULTS

HIF-1α protein levels and its target genes vascular endothelial growth factor, heme oxygenase-1, and insulin-like growth factor 1 were markedly increased after intraperitoneal injection of CoCl2 (60mg/kg). The target gene inducible nitric oxide synthase exhibited a biphasic time course. HI caused apoptosis and reduced capillary density, which were ameliorated by CoCl2. Both preconditioning with CoCl2 24h before HI and administration of CoCl2 24h after HI improved long-term reference memory compared with that in vehicle-injected littermate controls. Administration of CoCl2 immediately after HI did not improve spatial working memory.

CONCLUSIONS

CoCl2 activates HIF-1α and protects against brain damage in vivo. The time of administration could be used to manipulate the activity of HIF-1α pathways and promote recovery.

摘要

背景

缺氧缺血（HI）诱导的围产期脑病是急性死亡以及慢性神经疾病（如脑瘫、智力障碍和癫痫）的主要原因。作为缺氧诱导基因激活的关键转录因子，缺氧诱导因子1α（HIF-1α）在对HI脑损伤应激的病理生理反应中起重要作用。HIF-1α激活是否促进HI组织中的神经保护存在争议。

方法

对7日龄大鼠在麻醉下结扎左侧颈总动脉。然后将幼崽置于充满8%氧气和92%氮气的常压舱中缺氧2.5小时。在假手术对照组中，暴露左侧颈总动脉但不结扎或不暴露于缺氧环境。为评估有效治疗的时间窗，在手术前1天、手术时或手术后1天皮下注射HIF-1α诱导剂氯化钴（CoCl2）。在损伤后1天、2天和7天从每组幼崽中采集脑组织，检测HIF-1α蛋白及其靶基因表达，并研究损伤情况。在出生后7周进行莫里斯水迷宫试验。

结果

腹腔注射CoCl2（60mg/kg）后，HIF-1α蛋白水平及其靶基因血管内皮生长因子、血红素加氧酶-1和胰岛素样生长因子1明显升高。靶基因诱导型一氧化氮合酶呈现双相时间进程。HI导致细胞凋亡并降低毛细血管密度，CoCl2可改善这些情况。与注射溶剂的同窝对照相比，HI前24小时用CoCl2预处理以及HI后24小时给予CoCl2均改善了长期参考记忆。HI后立即给予CoCl2未改善空间工作记忆。