内毒素致豚鼠血迷路屏障通透性及其超微结构观察

Effect of lipopolysaccharide on the permeability of blood labyrinth barrier in guinea pigs

目的研究内毒素(ETX)致豚鼠血迷路屏障的动态变化情况。方法采用听泡内注入内毒素,以伊文思蓝(Evans B lue,EB)为示踪剂,测量EB通过耳蜗血迷路屏障的渗出量,应用透射电镜观察耳蜗外侧壁形态学的变化。结果内毒素使耳蜗血迷路屏障EB渗出量随时间的变化而变化,12 h开始有EB渗出,24 h达高峰,与12、72 h比较,有显著性差异。生理盐水组超微结构无变化,内毒素组血管纹血管内皮细胞呈不同程度的损伤,细胞间的间隙增宽,有炎性细胞浸润。结论内毒素能使血迷路屏障通透性增加,其原因主要是由血管纹微血管内皮细胞连续性中断及细胞间的紧密连接开放所致。

Objective To investigate the change of the permeability of endotoxin-induced blood-labyrinth barrier （BLB） in guinea pigs. Methods Endotoxin was injected into each tympanic cavity of 27 guinea pigs via superior bulla and Evans blue （EB） was injected via jugular vein before sacrification. Another 27 guinea pigs were served as control by injecting normal saline instead of endotoxin. On 12, 24, 72 h after injection of endotoxin or normal saline, EB content in BLB was detected after the cochlea were immersed in formamide for 24 h and the pathological change of lateral wall was observed by light microscope and transmission electron microscope. Results The BLB permeability to EB increased in endotoxin-induced cochlea of guinea pigs with prolonged time, and the content of EB was significantly different at 24 h in endotoxin-treated cochlea as com- pared with that at 12 h and 72 h. No marked morphological changes in the stria vascularis and spiral ligament were observed in control group. The pathologic changes in the lateral wall of cochlea in endotoxin-treated group were inflammatory cell infiltration, blood capillary engorgement, intercellular conjunction cleft. Conclusion The BLB permeability can be increased by endotoxin in the cochlea of guinea pigs, which is mainly caused by the capillary interendothelial cleft and continuous break of endothelial cells in stria vascularis.