Background: Leishmaniasis is a major tropical and subtropical parasitic disease. Sodium stibogluconate, N-methyl -D-glucamine antimoniate, amphotericin B, pentamidine, and ketoconazole are drugs used to treat this disease. Some of these drugs cause severe adverse side effects and treatment failures are common. Allopurinol, a purine analog, has been used to treat leishmaniasis, alone or combined with the previously mentioned drugs. Low cost, ease of administration (oral), and lack of toxicity make allopurinol a particularly appealing candidate. Methods: The effect of allopurinol on Leishmania infantum (MCAN/ES/89/IPZ229/1/89, zymodeme MON1) wildtype promastigotes (wt-p229), and an altered form of these promastigotes (allo-p229) resulting from long term in vitro exposure to allopurinol, was determined by [ 3 H]thymidine incorporation assays and by diverse flow cytometric approaches.
Results: Allopurinol arrested the proliferative capacity of wt-p229 promastigotes, reduced the proportion of viable cells, and decreased their total protein content. In contrast, allo-p229 promastigote proliferation was only slightly decelerated and the proportion of viable cells and the protein content were not affected by the allopurinol treatment.
Conclusions:
The flow cytometry approach allowed us to demonstrate differences in allopurinol susceptibility of the two promastigote forms, expanding the spectrum of flow cytometry applications in studies of parasite resistance. Cytometry 40:353-360, 2000.