Kinetics of Blood Protein Leakage in Inflammation

Abstract

A method has been developed for following the course of the inflammatory reaction by assaying the radioactivity changes of the skin of rats injected intravenously with radioiodinated human serum albumin (RISA). For this purpose, the term "clearance" has been introduced. It defines the amount of blood, in milliliters, completely cleared of radioactive material by 1 Gm. of dry skin. The initial reaction follows strictly a course described by the formula a = b t^c, where (a) is the difference between the average clearance of the inflamed and normal skin samples, (t) is the time in minutes, and (b) and (c) are constants. For normal-, medium-, and large-sized rats, as well as adrenalectomized animals, subjected to Xylene irritation, the (c) value was characteristically constant and equal to 2. Heat injury, on the other hand, is characterized by a lower exponent. The value of the constant (b) varied with the experimental group. The functional or anatomical factors reflected in these constants are not established. Nutritional blood flow was determined at close intervals during the development of the inflammatory reaction. It is postulated that the characteristic kinetics of the transudation of blood proteins into the inflamed skin reflects the changes in nutritional blood flow and vascular-exchange area which accompany the development of the reaction. The view is expressed that the passage of smaller molecules across normal vessel walls is likewise regulated by changes in blood flow and extent of vascular exchange.