大肠杆菌内毒素对小鼠血管通透性的影响

本文应用胶体碳作为示踪物,对小鼠在大肠杆菌内毒素引起休克时的肺,小肠和膈肌进行了血管通透性的形态学研究。 结果表明,注射内毒素30min后,属於体循环系统的支气管微静脉。小肠粘膜下层的微静脉以及膈肌血管树的微静脉及毛细血管后徼静脉段开始有碳黑颗粒沉着,这些徼静脉在电镜下发现为内皮细胞间连结开放,碳黑颗粒通过开放的连结进入内皮下,形成静脉漏,或称碳漏。它是血管通透性增高的标志之一。随着内毒素作用时间的延长,微静脉漏的数目增加,表明内毒素对血管通透性的影响,随着休克进展而不断加重。但属於肺循环系统中的微血管,只见毛细血管管腔内嗜中性白细胞、血小板逐渐增多,在内毒素注射后60min,嗜中性白细胞的特殊颗粒减少,吞噬泡出现,并发现这些血液有形成分粘附在内皮细胞表面,说明肺微血管的变化和血管通透性变化是相应的。最后对微静脉漏产生的可能机制进行了讨论。

Studies on Vascular Permeability after Injection of Escherichia coli Endotoxin in Mice

Using colloidal carbon as a tracer, morphologic studies of the vascular permeability on the lung, intestine and diaphragm were carried out in mice following Escherichia coli endotoxin injection.Shock was produced in 10 mice by injecting endotoxin intraperitoneally. Four untreated mice served as controls. Colloidal carbon was injected intravenously to detect the sites of pathologic increase in vascular permeability. Intramural deposits of carbon particles were only found in venules and were located in adventitia of bronchi in the lung and lamina pro-pria and submucosa of intestine. Similar deposits also were seen in venules and postcapillary venules of whole amount preparations of diaphragms. The number of leaky venules and postcapillary venules were progressively increased 1 h and 3 h after injecting endotoxin. On the contrary.no leaky venules were observed in the control group and in mice 15 minutes after endotoxin injection. At the electron microscopic level,the carbon labeling of venules and postcapillary venules was due to accumulation of carbon particles in their adventitia,ie,between endothelia and pericytes. Most of the leaky venules and postcapillary venules showed intact endothelia.But some interendothelial junction had been opened, allowing the passage of colloidal particles. We attributed the increased permeability of small blood vessels to the opening of endothelial junctions.In addition, pulmonary capillaries were engorged with polymorphonu-clear leukocytes, red blood cells and platelets 30 minutes after injections of Escherichia coli endotoxin. The endothelial cellular membranes appeared fuzzy and indistinct at sites where polymorphonuclear leukocytes were adhering.It was noted that the cytoplasm contained large vacuoles and lost the specific granules 60 minutes postinjection.The possible mechanism of leaky venules and postcapillary venules produced by Escherichia coli endotoxin were discussed