Inflammation, counter irritation and rat serum acute phase alpha 2-macroglobulin levels

Following the injection of turpentine and carrageenan into rats, laboratory models for counter irritation were assessed by measuring changes in paw thicknesses and serum acute phase alpha 2-macroglobulin concentrations. Both indices of inflammation were also examined in groups of rats dosed with 6-mercaptopurine, the best inhibitor found so far of elevated levels of alpha 2-macroglobulin in rat serum. Results showed that there is no relationship between the degree of irritant-induced inhibition of inflammation and the serum concentration of the acute phase protein. Hence, at least in the models for counter irritation used in this study, alpha 2-macroglobulin cannot be viewed as an endogenous anti-inflammatory protein.