A comparison of foreign body and hypersensitivity granuloma formation in the mouse: Kinetic development, anergy, angiotensin converting enzyme levels, and response to captopril therapy

Abstract

Pulmonary granuloma size, anergy, serum and lung angiotensin converting enzyme (ACE) levels, and responsiveness to captopril therapy were measured in both pulmonary hypersensitivity granuloma (HSG) and foreign body granuloma (FBG) murine models. The kinetic development of the granuloma was similar in both models, peaking at 3 days and resolving by 14 days. The granuloma size of the FBG model was significantly larger than the HSG model at 1 and 3 days. The FBG model further differed from the HSG model in that anergy was observed at 3 days and lung ACE levels were increased at 1, 7, and 14 days. In the HSG model anergy was not observed and lung ACE levels were significantly elevated only at 1 and 7 days. Furthermore, the HSG model was shown to be responsive to captopril therapy whereas the FBG model was not. This study shows that two murine pulmonary granuloma models, although displaying similar growth and resolution kinetics, differ in terms of granuloma size, anergy, lung ACE activity, and responsiveness to captopril therapy, suggesting that the mechanism(s) involved in the inflammatory response of the two models may be different.