ToxSci Advance Access originally published online on October 23, 2006
Toxicological Sciences 2007 95(1):289-296; doi:10.1093/toxsci/kfl138
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Pulmonary Biochemical and Histological Alterations after Repeated Low-Level Blast Overpressure Exposures
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* Department of Scientific Affairs, Hurley Consulting Associates, Chatham, New Jersey 07928
Department of Anatomy and Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203
Division of Military Casualty Research, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910
1 To whom correspondence should be addressed at Celgene Corp. Summit, NJ 07901. Fax: (908) 673-2792. E-mail: nelsayed{at}celgene.com.
Received July 19, 2006; accepted October 14, 2006
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Abstract |
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Blast overpressure (BOP), also known as high energy impulse noise, is a damaging outcome of explosive detonations and firing of weapons. Exposure to BOP shock waves alone results in injury predominantly to the hollow organ systems such as auditory, respiratory, and gastrointestinal systems. In recent years, the hazards of BOP that once were confined to military and professional settings have become a global societal problem as terrorist bombings and armed conflicts involving both military and civilian populations increased significantly. We have previously investigated the effects of single BOP exposures at different peak pressures. In this study, we examined the effects of repeated exposure to a low-level BOP and whether the number of exposures or time after exposure would alter the injury outcome. We exposed deeply anesthetized rats to simulated BOP at 62 ± 2 kPa peak pressure. The lungs were examined immediately after one exposure (1 + 0), or 1 h after one (1 + 1), two (2 + 1), or three (3 + 1) consecutive exposures at 3-min interval. In one group of animals, we examined the effects of repeated exposure on lung weight, methemoglobin, transferrin, antioxidants, and lipid peroxidation. In a second group, the lungs were fixed inflated at 25 cm water, sectioned, and examined histologically after one to three repeated exposures, or after one exposure at 1, 6, and 24 h. We found that single BOP exposure causes notable changes after 1 h, and that repeating BOP exposure did not add markedly to the effect of the first one. However, the effects increased significantly with time from 1 to 24 h. These observations have biological and occupational implications, and emphasize the need for protection from low-level BOP, and for prompt treatment within the first hour following BOP exposure.
Key Words: blast overpressure; explosive detonation; lung injury; repeated blast exposures; pulmonary biochemical and histological responses.