Observation of Liver Pathology after Praziquantel Treatment in Experimental Clonorchis sinensis Infection in Guinea Pigs

Abstract

The liver of guinea pigs infected experimentally with Clonorchis sinensis was grossly and histologically examined after treatment with praziquanteL Total 38 male guinea pigs were infected each with 300-500 metacercariae. Five weeks later praziquantel treatment was done on 28 animals, and repeated if needed. Remaining 10 were used for untreated controls, while 3 others were for uninfected controls. Liver examinations were done at 1, 2, 4 and/or 9 weeks following the treatment. Compared with uninfected controls, C sinensis-infected guinea pigs grossly revealed remarkably enlarged and swollen liver, with yellowish discolorations at surrounding portions of infected sites. Histologically these livers showed cystic hyperplasia of the bile ducts accompanied by irregular dilatation, glandular and/or papillary hyperplasia of the lining epithelia as well as periductal fibrosis. The livers of praziquantel-treated animals grossly revealed more of less recovering features later than 2 weeks after the treatment. Histologically, although adenomatous hyperplasia was quite subsided, other bile duct changes such as cystic hyperplasia and fibrosis were persistently retained in most animals until 9 weeks after the treatment. The results suggest that the liver damage induced by C sinensis is persistent for at least a few months after deworming with praziquantel.