Figure 5.

Effect of etazolate on parasite survival. Macrophages were preincubated with either increasing concentrations of rolipram and etazolate (1, 10, and 20 μM) or sodium stibogluconate (100 µg/ml) or left untreated for 30 min, followed by infection with L. donovani for another 72 h. The number of parasites per macrophage was scored for untreated (U) and treated systems by DAPI staining (A). Representative microscopic images of infected macrophages either untreated or treated with sodium stibogluconate (100 µg/ml), rolipram (20 µM) or etazolate (20 µM) are shown (B). BALB/c mice were infected with 10⁷ L. donovani promastigotes and treated etazolate (0–10 mg/kg/day). Etazolate was administered i.p. twice a week for 6 weeks starting at 1 week post-infection. PBS was used as vehicle control. The parasite burden in the liver and spleen was determined 6 weeks after infection and expressed as Leishman–Donovan Units (LDU). Disease progression was determined in the spleen (C) and liver (D) of mice that received etazolate at either 5 or 10 mg/kg/day twice weekly and parasite burden expressed as LDU at 2, 4, and 6 week post-infection (C, D). Results are representative of three individual experiments, and the data represent mean ± SD. ***P < 0.001, **P < 0.01 unpaired two tailed t test.