大鼠实验性冻结性冻伤微血管系统超微结构的研究

ULTRASTRUCTURAL STUDY ON THE MICROVASCULATURE IN THE RAT WITH EXPERIMENTAL FREEZING FROSTBITE

观察了大鼠后肢冷冻至－２０℃后即刻、４ｈ、２４ｈ及７２ｈ时微血管系统的超微结构改变。冻后即刻，皮下微血管系统及小动、静脉内皮细胞出现变性，少数内皮细胞发生坏死。冻后４ｈ，内皮细胞坏死脱落增多，并可见红细胞漏出腔外。冻后２４ｈ，皮下和深层微血管内皮均坏死，大部分内皮崩解脱落。有的小静脉内皮脱失殆尽，而由血小板直接贴附于基底膜上形成附壁血栓。冻后７２ｈ，除组织进一步坏死外，皮下间质中尚可见胶原纤维变性及格兰氏阴性杆菌侵入。

he ultrastructural changes in the microvasculature of the rat hindlimb cooled to-20℃ were observed.Biopsies were taken at 0,4,24 and 72h after freezing.Immediately after cold exposure,some of the endothelia in subcutaneous microvasculature,arteriolesand venules showed degeneration or necrosis.The number of the necrotic endothelia increased and some of which dropped into thecavity of the vessel 4h after cold exposure. Meanwhile,escaped erythrocytes were seen out of the vessel.All of the endothelia ofthe microvessel in subcutis and deep parts became necrosed and most of which broke into debris 4h after cold exposure.Thrombiforming by aggregated thrombocytes were seen on the basic membrane where endothelia disappeared.In addition to further necrosisof the tissues,degenerated collogen and Gram-negative bacilli were observed in the subcutaneous interstitia at 72h.