Autonomic responses to blast overpressure can be elicited by exclusively exposing the ear in rats  

作　　者：David S.Sandlin Yue Yu Jun Huang Chunming Zhang Alberto A.Arteaga John K.Lippincott Erin O.H.Peeden Ryan R.Guyton Lan Chen Laura L.S.Beneke Jerome C.Allison Hong Zhu Wu Zhou 

机构地区：[1]Graduate Program in Neuroscience, University of Mississippi Medical Center [2]School of Medicine, University of Mississippi Medical Center [3]Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center [4]Department of Otolaryngology, First Affiliated Hospital, Shanxi Medical University [5]Summer Undergraduate Research Experience, University of Mississippi Medical Center [6]Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center [7]Department of Neurology, University of Mississippi Medical Center

出　　处：《Journal of Otology》2018年第2期44-53,共10页中华耳科学杂志（英文版）

基　　金：supported by the United States National Institutes of Health[grant numbers:NIDCD R01DC014930(WZ),NIDCD R01DC012060(HZ)]

摘　　要：Blast overpressure has become an increasing cause of brain injuries in both military and civilian populations. Though blast＇s direct effects on the cochlea and vestibular organs are active areas of study, little attention has been given to the ear＇s contribution to the overall spectrum of blast injury. Acute auto- nomic responses to blast exposure, including bradycardia and hypotension, can cause hypoxia and contribute to blast-induced neurotrauma. Existing literature suggests that these autonomic responses are elicited through blast impacting the thorax and lungs. We hypothesize that the unprotected ear also provides a vulnerable locus for blast to cause autonomic responses. We designed a blast generator that delivers controlled overpressure waves into the ear canal without impacting surrounding tissues in order to study the ear＇s specific contribution to blast injury. Anesthetized adult rats＇ left ears were exposed to a single blast wave ranging from 0 to 110 PSI （0-758 kPa）. Blast exposed rats exhibited decreased heart rates and blood pressures with increased blast intensity, similar to results gathered using shock tubes and whole-body exposure in the literature. While rats exposed to blasts below 50 PSI （345 kPa） exhibited increased respiratory rate with increased blast intensity, some rats exposed to blasts higher than 50 PSI （345 kPa） stopped breathing immediately and ultimately died. These autonomic responses were significantly reduced in vagally denervated rats, again similar to whole-body exposure literature. These results support the hypothesis that the unprotected ear contributes to the autonomic responses to blast.Blast overpressure has become an increasing cause of brain injuries in both military and civilian populations. Though blast＇s direct effects on the cochlea and vestibular organs are active areas of study, little attention has been given to the ear＇s contribution to the overall spectrum of blast injury. Acute auto- nomic responses to blast exposure, including bradycardia and hypotension, can cause hypoxia and contribute to blast-induced neurotrauma. Existing literature suggests that these autonomic responses are elicited through blast impacting the thorax and lungs. We hypothesize that the unprotected ear also provides a vulnerable locus for blast to cause autonomic responses. We designed a blast generator that delivers controlled overpressure waves into the ear canal without impacting surrounding tissues in order to study the ear＇s specific contribution to blast injury. Anesthetized adult rats＇ left ears were exposed to a single blast wave ranging from 0 to 110 PSI （0-758 kPa）. Blast exposed rats exhibited decreased heart rates and blood pressures with increased blast intensity, similar to results gathered using shock tubes and whole-body exposure in the literature. While rats exposed to blasts below 50 PSI （345 kPa） exhibited increased respiratory rate with increased blast intensity, some rats exposed to blasts higher than 50 PSI （345 kPa） stopped breathing immediately and ultimately died. These autonomic responses were significantly reduced in vagally denervated rats, again similar to whole-body exposure literature. These results support the hypothesis that the unprotected ear contributes to the autonomic responses to blast.

关 键 词：Blast waves Autonomic responses EAR NEUROTRAUMA 

分 类 号：R764[医药卫生—耳鼻咽喉科]