The immunomodulatory effects of roflumilast on tachyzoite-bradyzoite transition in a murine model of Toxoplasma gondii.

Roflumilast, a phosphodiesterase 4-inhibitor (PDE-4), shows immunomodulatory and anti-inflammatory properties. It modulates cAMP and TNF-α levels that play a role in the differentiation of Toxoplasma gondii (T. gondii) tachyzoite to bradyzoite stage. Thus, the potential effect of Roflumilast on the tachyzoite-bradyzoite transition in Me49 murine toxoplasmosis using 36 female Swiss Webster mice was studied. The mice were divided into six equal groups; normal control, infected control, two groups treated earlier with Roflumilast at 5 mg/kg and 10 mg/kg, and two groups treated later with Roflumilast at 5 mg/kg and 10 mg/kg. The T. gondii infection was assessed by cyst count and size, measuring serological levels of TNF-α and IL-12 using ELISA kits, brain immunohistochemistry examination of INF-γ and iNOS expression and histopathological examinations of the brain, liver, and spleen. The early-Roflumilast treated group at 10 mg/kg showed a statistically significant of reduction of T. gondii cyst count, size, and IL-12 level. In contrast, TNF-α levels were lower in both the early-Roflumilast treated groups. IFN-γ and iNOS expression showed non-significant changes in the different Roflumilast treated groups associated with mild inflammatory reactions in the brain, liver, and spleen tissues of the early-Roflumilast treated groups that were statistically significant (p < 0.05). This study showed that the earlier treated group at 10 mg/kg halted better tachyzoite-bradyzoite transition than the other groups. The results indicated Roflumilast to be promising for toxoplasmosis control.