Morphological characterization of experimental amebic liver lesions in gerbils.

Gerbils are susceptible to amebic liver abscess (ALA) production under experimental conditions. However, little is known about the histopathological changes that occur during the evolution of the lesion. We analyzed microscopically the sequence of cellular events of ALA in gerbils inoculated intraportally or intrahepatically with E. histolytica. At early stages trophozoites were associated with different degrees of inflammatory reaction. Amebas were also observed in areas devoid of inflammatory cells. Damaged hepatocytes were either related or not to inflammatory reaction. At late stages, lysis of macrophages and epithelioid cells were seen in relation to necrotic tissue and trophozoites. We conclude that amebic liver necrosis in gerbils at early stages may result from lysis of inflammatory cells as shown previously by us in hamsters, but also by direct contact and lytic activity of amebas to hepatocytes. The late destruction and expansion of hepatic tissue necrosis is apparently associated with damage of macrophages and epithelioid cells.