Petras J M, Bauman R A, Elsayed N M
Department of Neurobehavioral Assessment, Walter Reed Army Institute of Research, Washington, D.C. 20307-5100, USA.
Toxicology. 1997 Jul 25;121(1):41-9. doi: 10.1016/s0300-483x(97)03654-8.
The effect of blast overpressure on visual system pathology was studied in 14 male Sprague-Dawley rats weighing 360-432 g. Blast overpressure was simulated using a compressed-air driven shock tube, with the aim of studying a range of overpressures causing sublethal injury. Neither control (unexposed) rats nor rats exposed to 83 kiloPascals (kPa) overpressure showed evidence of visual system pathology. Neurological injury to brain visual pathways was observed in male rats surviving blast overpressure exposures of 104-110 kPa and 129-173 kPa. Optic nerve fiber degeneration was ipsilateral to the blast pressure wave. The optic chiasm contained small numbers of degenerated fibers. Optic tract fiber degeneration was present bilaterally, but was predominantly ipsilateral. Optic tract fiber degeneration was followed to nuclear groups at the level of the midbrain, midbrain-diencephalic junction, and the thalamus where degenerated fibers arborized among the neurons of: (i) the superior colliculus, (ii) pretectal region, and (iii) the lateral geniculate body. The superior colliculus contained fiber degeneration localized principally to two superficial layers (i) the stratum opticum (layer III) and (ii) stratum cinereum (layer II). The pretectal area contained degenerated fibers which were widespread in (i) the nucleus of the optic tract, (ii) olivary pretectal nucleus, (iii) anterior pretectal nucleus, and (iv) the posterior pretectal nucleus. Degenerated fibers in the lateral geniculate body were not universally distributed. They appeared to arborize among neurons of the dorsal and ventral nuclei: the ventral lateral geniculate nucleus (parvocellular and magnocellular parts); and the dorsal lateral geniculate nucleus. The axonopathy observed in the central visual pathways and nuclei of the rat brain are consistent with the presence of blast overpressure induced injury to the retina. The orbital cavities of the human skull contain frontally-directed eyeballs for binocular vision. Humans looking directly into an oncoming blast wave place both eyes at risk. With bilateral visual system injury, neurological deficits may include loss or impairments of ocular movements, and of the pupillary and accommodation reflexes, retinal hemorrhages, scotomas, and general blindness. These findings suggest that the retina should be investigated for the presence of traumatic or ischemic cellular injury, hemorrhages, scotomas, and retinal detachment.
对14只体重在360 - 432克之间的雄性斯普拉格-道利大鼠研究了爆炸超压对视觉系统病理的影响。使用压缩空气驱动的激波管模拟爆炸超压，目的是研究一系列造成亚致死性损伤的超压情况。对照组（未暴露）大鼠和暴露于83千帕超压的大鼠均未显示视觉系统病理迹象。在爆炸超压暴露为104 - 110千帕和129 - 173千帕后存活的雄性大鼠中观察到脑视觉通路的神经损伤。视神经纤维变性与爆炸压力波同侧。视交叉含有少量变性纤维。视束纤维变性双侧均有，但主要在同侧。视束纤维变性一直追踪到中脑、中脑 - 间脑交界处和丘脑水平的核团，在这些核团中，变性纤维在以下神经元之间分支：(i) 上丘，(ii) 顶盖前区，以及 (iii) 外侧膝状体。上丘的纤维变性主要局限于两个浅层：(i) 视层（III层）和 (ii) 灰质层（II层）。顶盖前区含有广泛分布于以下区域的变性纤维：(i) 视束核，(ii) 橄榄顶盖前核，(iii) 前顶盖前核，以及 (iv) 后顶盖前核。外侧膝状体中的变性纤维分布并不普遍。它们似乎在背侧和腹侧核团的神经元之间分支：腹侧外侧膝状体核（小细胞和大细胞部分）；以及背侧外侧膝状体核。在大鼠脑的中央视觉通路和核团中观察到的轴突病与爆炸超压引起的视网膜损伤相符。人类颅骨的眶腔内有向前的眼球用于双眼视觉。直视迎面而来的爆炸波会使双眼处于危险之中。双侧视觉系统损伤时，神经功能缺损可能包括眼球运动、瞳孔和调节反射的丧失或受损、视网膜出血、暗点和完全失明。这些发现表明，应检查视网膜是否存在创伤性或缺血性细胞损伤、出血、暗点和视网膜脱离。
