Histopathological Changes of Hydatidosis in the Liver and Spleen of Albino Mice: Dose Effect Changes


Background: A number of investigators have carried out experimental infections of hydatidosis or cystic echinococcosis, using albino mice as an experimental animal model, but there has been disagreement about the effect of the parasite infective dose on the outcome of infection. Studies, which have been carried out in Iraq and other places used protoscolices (PSCs) to produce cystic echinococcosis, but the inoculation dose showed variations.Objectives: This study was established to shed light on the relationship between the number of injected PSCs and the pathological changes that consequently occur in the liver and spleen, as these organs have a role in the immune status of the host, and they are a target for such an infection.Materials and Methods: Ninety male mice aged 7-8 weeks were injected intraperitoneally with 6 doses (250, 500, 1000, 1500, 2000, 2500) of PSC/mouse. Fifteen mice were injected for each dose. All doses were paralleled by one control group of 15 mice injected with normal, saline. Five animals were sacrificed at one, two and four month post-injection. Their livers and spleens were collected for histopathological examination.Results: Microscopical examination of livers and spleens of animals injected with doses: 250, 500, 1000, 1500, 2000 and 2500 PSCs/ mouse showed severe pathological changes which increased with dose and period post-infection.Conclusion: Both liver and spleen were affected in mice injected with different doses of PSCs, even if it did not show a well developed cyst. These effects were greater as the doses and post-infection period increased, especially in the four months post- infection. Key words: Histopathological changes, hydatidosis, liver and spleen, albino mice, dose effect.