IJCEP Copyright © 2007-All rights reserved.
Int J Clin Exp Pathol 2013;6(3):375-384

Original Article
Relationship between changes in the cochlear blood flow and disorder of hearing
function induced by blast injury in guinea pigs
  
Wei Chen, Jianmin Wang, Jing Chen, Jichuan Chen, Zhiqiang Chen

Research Institute of Surgery, State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Third Military Medical University,
Chongqing 400042, China; Department of Otorhinolaryngology, Daping Hospital, Third Military Medical University, Chongqing 400042, China

Received November 20, 2012; Accepted January 11, 2013; Epub February 15, 2013; Published March 1, 2013

Abstract: The auditory system is the most susceptible to damages from blast waves. Blast injuries always lead to varying degrees of hearing
impairment. Although a disorder of the cochlear blood flow (CoBF) has been considered to be related to many pathological processes of the
auditory system and to contribute to various types of hearing loss, changes in the CoBF induced by blast waves and the relationship between
such changes and hearing impairment are undefined. To observe the changes in the cochlear microcirculation after exposure to an explosion
blast, investigate the relationship between changes in the CoBF and hearing impairment and subsequently explore the mechanism
responsible for the changes in the CoBF, we detected the perfusion of the cochlear microcirculation and hearing threshold shift after exposure
to an explosion blast. Then, an N-nitro-L-arginine-methyl ester (L-NAME, NO synthase inhibitor) solution and artificial perilymph were applied to
the round window (RW) of the cochlea before the blast exposure, followed by an evaluation of the CoBF and hearing function. The results
indicated that the changes in the CoBF were correlated to the strength of the blast wave. The cochlear blood flow significantly increased when
the peak value of the blast overpressure was greater than approximately 45 kPa, and there was no significant change in the cochlear blood flow
when the peak value of the blast overpressure was less than approximately 35 kPa. Following local administration of the NO synthase inhibitor
L-NAME, the increase in the CoBF induced by the blast was inhibited, and this reduction was significantly associated with the hearing
threshold. (IJCEP1211020).

Keywords: Cochlea, blood flow, hearing function, blast injury, guinea pigs

Address correspondence to: Dr. Jianmin Wang, State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery,
Daping Hospital, Third Military Medical University, No.10, Changjiang Zhilu, Chongqing 400042, China. Tel: +86 023 68757461; Fax: +86 023
68757461; E-mail: wang7896789@sina.com; chenjing9811@dphospital.tmmu.edu.cn