[Experimental intestinal amebiasis: invasion and extension of the amebic lesion].

A morphological analysis of an experimental model of invasive intestinal amebiasis was carried out using the washed-closed cecal loop model in hamsters and guinea-pigs. By light microscopy, few amebic trophozoites adhered to the intestinal epithelium, whereas many associated to the mucus blanket. Some trophozoites attached to the interglandular epithelium, during the first 10 to 15 hours of interaction. Hereafter, the parasites destroyed gradually the epithelium and were associated with normal and lysed inflammatory cells. Some amebas have cell debris and erythrocytes in their cytoplasms. Typical amebic ulcer contained abundant trophozoites at the basolateral area. The results suggest that intestinal mucus and muscularis mucosa are temporal barriers to amebic invasion and extension of the ulcer. At the mucosal and submucosal levels, lysis of inflammatory cells produced by amebas seems to play an important role in the extension of the ulcer.