Role of PMN-Leukocyte Lysosomes in Tissue Injury,Inflammation And Hypersensitivity. V. Partial Suppression in Leukopenic Rabbits of Vascular Hyperpermeability Due to Thermal Injury. ∗

Summary

Increase in vascular permeability was induced in rabbits with the aid of heat (56°C for 20-60 seconds) applied to the abdominal skin. It was shown that in animals rendered leukopenic the increase in vascular permeability is milder following heat injury. The skin lesions showed infiltration with PMN-leukocytes, which when examined ultrastructurally showed degenerative changes and signs of degranulation. There were no leukocytes in the skin lesions of leukopenic rabbits. It was concluded that the PMN-leu-kocyte, presumably its lysosomes, contribute to the pathogenesis of the late phase of increased vascular permeability due to heat injury. The role of these lysosomes in other forms of vascular injury and their possible mode of action was discussed.