Skin edema model. Vascular permeability leading to mouse skin edema was assayed as described previously (47). Mice were injected via the tail vein with 0.2 ml of 1.5% FITC-BSA (15 mg/ml) in isotonic Tyrode solution, which served as a tracer of vascular permeability. Thereafter, serum exudation was induced by subcutaneous injection of histamine (1 μg/100 μl/site) into the shaved dorsal skin. Thirty minutes later, the injected sites in the dorsal skin were removed as circular patches and put into the wells of a 24-well culture plate. Formamide (1 ml) was then added to each well and incubated at 50°C for 2 h, after which the fluorescence intensity in each well was measured using a Multi-Detection Microplate Reader; the excitation and emission wavelengths were 485 nm and 530 nm, respectively.