次声作用后SD大鼠视网膜内皮素-1表达及超微结构改变

目的:探讨次声作用后SD大鼠视网膜内皮素-1表达及超微结构改变。方法:雄性SD大鼠25只,分为5组,每组5只,除未经次声作用对照组外,余4组放入次声舱,经16 Hz、130 dB每日暴露2 h, 分别于1,7,14和21 d硝酸镧静脉灌注后处死动物, 取视网膜组织用电镜和免疫组化检测超微结构改变和内皮素的表达。结果:对照组和次生作用1d,内皮素表达在视网膜和脉络膜血管内皮,次声作用后,内皮素主要表达在视网膜的色素上皮层和外颗粒层,外丛状层也有较弱的表达;而14d主要表达在外丛状层,内核层和节细胞层阳性表达加强。21d视网膜各层表达均减弱;随着次声作用时间的延长,视网膜组织表现由外向内的损害。电镜下,随次声暴露时间的延长,除7d外镧的渗入也逐渐加重,视网膜各层出现细胞水肿,细胞器肿胀,染色质浓缩边集,细胞变性坏死和细胞膜断裂和髓样等改变。结论:内皮素的表达与视网膜次声损伤部位相关,可能是对损伤的一种修复反应。

ET-1 expression and ultrastructural changes in the retina after exposure to infrasound in rats

AIM: To evaluate the expression of ET-1 and ultrastructural changes in the retina of Sprague-Dawley rats after exposure to infrasound.METHODS: Twenty five male Sprague-Dawley rats were divided into 5 groups, 5 in each group, and 4groups were exposed to infrasound of 16 Hz, 130 dB for 2 hours each day, and 1 group served as control. The exposure time for the 4 groups was respectively 1, 7, 14and 21 days. Then, the rats were sacrificed after intravenous irrigation with lanthanum nitrate (La), and the retina was examined with electron microscopy and immunochemistry with antibodies against ET-1.RESULTS: After infrasonic exposure for 1 day, ET-1 expressed mainly in the endothelium of retinal and choroidal blood vessels. So did it in the control group. After infrasonic exposure for 7 days, it expressed mainly in the retinal pigment epithelial cells, outer nuclear layer and outer plexiform. After exposure for 14 days, its expression was enhanced in the outer nuclear layer, inner plexiform layer and ganglion cell layer. After exposure for 21 days,its expression was weakened in all layers. With exposure going on, the injury in retina gradually extended from the outer to the inner. Under the electronic microscope, La was observed to have filtered into several layers of the retina after 1 day of exposure and it became denser and denser from the 1st to the 21st day except at the 7th day. Meanwhile, the retinal layers showed cellular edema, swollen organelles such as mitochondrion and endoplasmic reticulum, karyopyknosis and edging, cell membrane and karyotheca dilation, rupture and myelin figure.CONCLUSION: The expression of ET-1 in retina is related to the location of infrasonic injury, and ET-1 may have a protective effect on retina against the infrasonic injury.