Bauman R A, Elsayed N, Petras J M, Widholm J
Department of Neurobehavioral Assessment, Walter Reed Army Institute of Research, Washington, DC 20307-5100, USA.
Toxicology. 1997 Jul 25;121(1):65-79. doi: 10.1016/s0300-483x(97)03656-1.
Exposure to blast overpressure can typically inflict generalized damage on major organ systems, especially gas-containing organs such as the lungs and the gastrointestinal tract. The purpose of the present study was to use rat's food intake and exercise wheel running as behavioral correlates of the perhaps more subtle damage to these organ systems induced by sublethal blast overpressure. Toward this end, all rats were exposed to a 12-h light/dark cycle and food was available only in the dark period. Prior to exposure, rats in the (E)xercise group were required to execute five rotations of an activity wheel for a food pellet; wheel turns that occurred at times other than when a rat was feeding were recorded separately and labeled exercise running. In the (S)edentary and (A)nesthesia groups, wheel running was not possible and rats were required to execute five leverpresses for a single pellet. A compressed air-driven shock tube was used to expose rats to a supra-atmospheric wave of air pressure. The tube was separated into two sections by a polyester membrane, the thickness of which determined peak and duration of overpressure. All rats were anesthetized with 50 mg/kg of phenobarbital. After reaching a deep plane of anesthesia, they were individually tied in a stockinet across one end of the shock tube. In preliminary tests, the membrane thickness was 1000 (A)ngstroms and rats in Group L(ethality) were exposed to a 129 kPa (peak amplitude) wave of overpressure. Three of six rats survived exposure to this peak pressure; pathology was evident in the lungs and gastrointestinal tract of all non-survivors. Rats in Groups E and S were tested with a 500 A membrane, which resulted in an 83 kPa peak amplitude. All rats survived exposure to this lower peak pressure. On the day of exposure to blast, the relative reduction of intake during the first 3 h of the dark period was significantly greater for Group E than for Groups S and A; the intake of Groups E and S remained reduced for four additional recovery days. Bodyweight was not significantly affected. Exercise wheel running also was reduced significantly on the day of exposure and during subsequent recovery days. These preliminary findings suggest that exposure to sublethal blast overpressure can reduce food consumption and exercise performance, perhaps as a consequence of damage to the gastrointestinal tract and lungs.
暴露于爆炸超压通常会对主要器官系统造成全身性损害，尤其是对含气器官，如肺和胃肠道。本研究的目的是利用大鼠的食物摄入量和在运动轮上的奔跑情况，作为亚致死性爆炸超压对这些器官系统造成的可能更为细微损害的行为相关指标。为此，所有大鼠均处于12小时光照/黑暗周期中，且仅在黑暗期提供食物。在暴露前，运动组（E组）的大鼠需要转动活动轮五次以获取一粒食物颗粒；在大鼠进食时间之外发生的转轮次数会被单独记录并标记为运动奔跑。在久坐组（S组）和麻醉组（A组）中，大鼠无法进行转轮活动，它们需要按压杠杆五次才能获取一粒食物颗粒。使用压缩空气驱动的冲击管使大鼠暴露于超大气压的气压波中。该管由聚酯膜分为两部分，聚酯膜的厚度决定了超压的峰值和持续时间。所有大鼠均用50mg/kg的苯巴比妥麻醉。达到深度麻醉平面后，将它们分别用弹力织物绑在冲击管一端。在初步试验中，膜厚度为1000埃，致死组（L组）的大鼠暴露于129kPa（峰值幅度）的超压波中。六只大鼠中有三只在暴露于该峰值压力后存活；所有非存活大鼠的肺和胃肠道均出现明显病变。E组和S组的大鼠用500埃的膜进行测试，这导致峰值幅度为83kPa。所有大鼠在暴露于这个较低的峰值压力后均存活。在暴露于爆炸的当天，黑暗期前3小时E组的摄入量相对减少幅度显著大于S组和A组；E组和S组的摄入量在另外四天的恢复期内仍持续减少。体重未受到显著影响。在暴露当天及随后的恢复期内，运动轮上的奔跑活动也显著减少。这些初步研究结果表明，暴露于亚致死性爆炸超压可能会减少食物消耗和运动表现，这可能是胃肠道和肺受损的结果。
