Article

Blockade of the swelling-induced chloride current attenuates the mouse neonatal hypoxic-ischemic brain injury in vivo

Authors: Raymond WONG1,2, Ahmed ABUSSAUD1,2, Joseph WH LEUNG1,2, Bao-feng XU1,2, Fei-ya LI1,2, Sammen HUANG1,2, Nai-hong CHEN3, Guan-lei WANG4, Zhong-ping FENG2, Hong-shuo SUN1,2,5,6
1 Departments of Surgery
2 Physiology
3 Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
4 Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
5 Pharmacology, and
6 Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 1A8
Corresponding to: Hong-shuo SUN: hss.sun@utoronto.ca,
DOI: 10.1038/aps.2018.1
Received: 7 November 2017
Accepted: 2 January 2018
Advance online: 29 March 2018

Abstract

Abstract
Activation of swelling-induced Cl current (ICl,swell) during neonatal hypoxia-ischemia (HI) may induce brain damage. Hypoxic-ischemic brain injury causes chronic neurological morbidity in neonates as well as acute mortality. In this study, we investigated the role of ICl,swell in hypoxic-ischemic brain injury using a selective blocker, 4-(2-butyl-6,7-dichloro-2-cyclopentylindan-1-on-5-yl) oxybutyric acid (DCPIB). In primary cultured cortical neurons perfusion of a 30% hypotonic solution activated ICl,swell, which was completely blocked by the application of DCPIB (10 μmol/L). The role of ICl,swell in neonatal hypoxic-ischemic brain injury in vivo was evaluated in a modified neonatal hypoxic-ischemic brain injury model. Before receiving the ischemic insult, the mouse pups were injected with DCPIB (10 mg/ kg, ip). We found that pretreatment with DCPIB significantly reduced the brain damage assessed using TTC staining, Nissl staining and whole brain imaging, and improved the sensorimotor and vestibular recovery outcomes evaluated in neurobehavioural tests (i.e. geotaxis reflex, and cliff avoidance reflex). These results show that DCPIB has neuroprotective effects on neonatal hypoxic-ischemic brain injury, and that the ICl,swell may serve as a therapeutic target for treatment of hypoxic-ischemic encephalopathy.
Keywords: neonatal stroke; neonatal hypoxic-ischemic brain injury; volume regulated anion channels; chloride channels; cortical neurons; whole-cell recording; DCPIB; neurobehavioural tests; neuroprotection