Rate of protein extravasation in inflammation

¹ Department of Dermatology, Stanford Medical Center, Palo Alto, California

Radioalbumin was used to study the course of the inflammatory reaction induced in rats by the topical application of xylene. The water content of normal skin was found to amount to 57.49% (sd = 3.6) of its weight, and to increase continuously throughout the duration of the inflammatory reaction. The intravascular volume of the normal skin amounts to 3.63% of its weight, corresponding to 0.0237 ml plasma/g normal skin. One minute after the application of xylene, blood plasma begins to leak out of the vessels at the rate of 0.0468 ml plasma/min g normal skin. The rate of protein extravasation does not remain constant, but increases linearly with time for the next 3.5 min, when it reaches a maximum. This relation is interpreted as resulting from the continuous application of a constant phlogogenic stress on the system. After the peak is reached, the rate of protein extravasation decreases exponentially with time, with a time constant equal to –0.2236 min^–1 (t_1/2 = 3.1 min). The kinetics of this phase of the reaction is thought to result from a number of parallel exponential processes.

Key Words: capillary permeability • inflammation • kinetics of inflammation • protein extravasation • vascular permeability • protein permeability

Submitted on June 17, 1963