Measurement of cutaneous microvascular exudates using Evans blue

As an approach to the study of inflammation, strategies were evaluated for quantitative assessment of plasma exudate from the cutaneous microvasculature. Measurements were based on recovery of Evans blue dye (EB) from rat skin. After preliminary studies to evaluate extraction methods, almost complete EB recovery was accomplished by homogenizing tissue in a mixture of acetone, water and sodium sulfate. When sources of potential variation were identified, expression of results as agonist-induced plasma accumulation provided precise results based on EB measurements. Also, the feasibility of parallel biochemical studies was demonstrated.