Abstract: Objective To evaluate the efficacy of dephnetin in the treatment of pneumocystis carinii pneumonia(PCP) in rat models. Methods The PCP animal model was made by subcutaneously injecting prednisolone acetate in female Wistar rat. All experimental rats were randomly divided into 5 groups: group A was normal control; group B was control with no drug for treatment; group C was control given TMP-SMZ; group D was rats given dephnetin; group E was control given dihydroarteminsinin(DHA). The efficacy of dephnetin on the treatment of PCP was evaluated by altration in ratio of lung weight to body weight and the burden of Pneumocystis carinii. Results The mortality of the experimental rats immunosuppressed by prednisolone acetate was 16.7% in six weeks. The mean ratios of lung weight to body weight in groups A～E were 0.75, 1.05, 0.77, 0.77, and 0.85 respectively. And the mean counts of Pneumocystis carinii cyst/mg of lung in groups B~E were 1 490, 74, 339, and 219 respectively. The mean ratio of lung weight to body weight and the mean count of Pneumocystis carinii cyst/mg of lung in groups C, D and E were significantly lower than those of the control group B with no drug for therapy(P<0.05 and P<0.01). Although the efficacy of dephnetin was not better than those of TMP-SMZ, there was no difference between the efficacy of dephnetin and DHA. Conclusion Dephnetin is effective in the treatment of PCP in rat models, and its therapeutic efficacy is similar to that of DHA.

Key words: pneumocystis carinii pneumonia(PCP), rat model, dephnetin