Inflammatory exudates in skin windows induced by 1-0-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine.

Previously identified as a platelet-activating factor, 1-0-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine recently has been described as an inflammatory mediator with vasoactive and leukotactic properties. Histologic studies suggested that the local microvascular effects of this potent acetylated alkyl phosphoglyceride were limited in extent. Also, cytologic characterization of exudates was incomplete in tissue sections. Therefore, skin window chambers were used as an alternate model in which to explore the ability of the active form of this lipid mediator to diffuse in tissue. In addition, skin windows provided a convenient means to characterize the leukocytic exudates. Based on measurements of agonist-induced plasma exudation, the effect of 1-0-hexadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine appeared to be limited to the superficial microvasculature underlying the skin window surface. This interpretation was supported by a brief histologic study that revealed vascular labeling by colloidal carbon mostly in a narrow 150-microns dermal zone beneath chambers containing the phospholipid agonist. Finally, the leukocytic exudate recovered at 3 hours consisted of neutrophils and a small number of eosinophils. Thus the skin window model was useful to further characterize the leukocytic exudate, and it suggested that the potent vasoactive effects of the acetylated alkyl phosphoglyceride were limited by local conditions in tissue so as to produce a highly focused inflammatory response.