Captopril reduces collagen and mast cell and eosinophil accumulation in pig serum-induced rat liver fibrosis

The effect of captopril on the development of hepatic septal fibrosis in a specific experimental model produced by repeated injections of whole pig serum into the peritoneal cavity of rats was studied. The results afforded four basic conclusions. First, the experimental model used seems to be a pure form of septal fibrosis, which depends on active tissue fibroplasia, without hepatocyte necrosis. The fibrotic septa, located between limiting plates of adjacent classic hepatic lobules, and delimiting the classic liver lobule, consisted of collagen fibers infiltrated by eosinophils, mast cells, fat-storing cells (Ito cells), transitional cells and interstitial fibro-blasts. Second, the angiotensin-converting enzyme inhibitor captopril attenuated the hepatic fibrosis induced by pig serum administration, as proven by a decrease In hepatic hydroxyproline concentration and histological examination of the liver. Third, this attenuation of hepatic fibrosis might be related, at least in part, to diminished mast cell and eosinophil accumulation in the hepatic tissue. Finally, these data may indicate a novel action of angiotensin-converting enzyme inhibitor in general, and for captopril in particular, as drugs potentially capable of reducing eosinophils in fibrotic processes.