Effects of platelet activating factor (PAF) and other vasoconstrictors on a model of angiogenesis in the mouse.

The combination of sponge implant and 133Xe washout technique described in this paper provides a model to study neovascularization in mice which can be observed over several days in the same animal. The local blood flow within the ingrowing granulation tissue has been determined by measuring the washout rate of 133Xe injected into the implants. Tissue infiltration of the sponges was assessed by histological examination and by measurement of sponge wet weight, protein and glycosaminoglycans (GAG) content. The newly formed blood vessels, despite having abnormal configuration, responded to platelet activating factor (PAF) and to endothelin-1 (ET-1) similarly to the normal mature vessels in adjacent skin. However, the sponge blood vessels were more sensitive to angiotensin II than the skin blood vessels. Using this model we have also demonstrated an angiogenic activity of PAF substantiated by increased blood flow and biochemical variables in the implanted sponges.