An experimental study was performed to observe chemotherapeutic an chemoprophylactic effects praziquantel (distocide(R)) against Clonorchis sinensis infection of rats. The metacercariae of C. sinensis obtained from the naturally
infected
Pseudorasbora parva and about 200g of rats (Sprage-Dawly) conventionally reared in laboratory were used.
For the observation of vitro effect, metacercariae were incubated in 0(control group), 0.1,1.0,10 and 100 g/ml praziquantel solution and infected to rats. To observe in vivo effects 5~9 rats per group were treated with doses of 25, 50 and
100mg/kg of praziquantal at 6, 3 and 1 hour after infection respectively. All experimental rats including the control group were infected with 50 metacercariae and sacrificed 6 weeks later to evaluate the killing effects of drug
based on
the recovery rates of worms. Followings are summarized recovery rates of worms. Following are summarized results.
1. In in vitro experiment, the recovery rates of 0.1 and 1.0 g/ml group were not so different from that of control, but those of 10 and 100 g/ml groups were significantly decreased.
2. The average recovery rate from the other in vivo experimental group treated with 25mg/kg at 6 hours before infection was 30%. Those from the other in vivo experimental group were 0~1.2%.
3. The chemoprophylatctic effects were seen in group given 100mg/kg at 6 hours before infection, 25, 50 and 100mg/kg at 3 hours and 1 hour before and 1 hour after infection.
From the above results, it was confirmed that praziquantel is highly effective to Clonorchis sinensis metacercariae and showed a good prophylactic effet if the medication dosage and timing are adequate.
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