Abstract: 　Objective To observe the effect of acryl thiourea, an inhibitor of phenol oxidase, on pathological changes in the liver of mice infected with Schistosoma japonicum . Methods From day 22 to day 42 postinfection with cercariae, the mice of the acryl thiourea group were each injected i.p. with acryl thiourea at a dose of 300 mg/kg every other day. The mice were killed on the 42nd day postinfection to observe the pathological changes in the liver. Results Compared to the infected control group, the liver tissue of the acryl thiourea group showed scattered foci of inflammatory cell infiltration, the mean diameter and area of the foci were significantly reduced ( P <0.01), and there were no eggs in the center of the foci except for some granules. Conclusion After i.p. injections of acryl thiourea, no typical egg granuloma was found in the liver of infected mice. This was possibly due to the inhibition of schistosome phenol oxidase activity and so the female adult schistosomes could not produce normal eggs.

Key words: Schistosoma japonicum, acryl thiourea, liver pathologic change