Evaluating the Inhibitory Effects of Colchicine and Propranolol on Toxoplasma gondii Entrance into Host Cells in vitro and in vivo

Toxoplasma gondii is a zoonotic parasite of increasing concern to humans and animals. Considering the side effects of drugs used to treat toxoplasmosis, it is essential to find alternative drugs.

In this study, colchicine and propranolol at four concentrations (1, 5, 10, and 15 µg/mL) were added to the RPMI medium containing peritoneal macrophages and incubated for 60 min, Then tachyzoites were added to the medium, and the efficacy rates of colchicine and propranolol in inhibiting tachyzoites entry into macrophages were evaluated after 30 and 60 min. For in vivo assay, one group received no drugs, and the second group was treated with colchicine and propranolol at different concentrations for different durations.

The in vitro experiment showed that treatment with 15 mg/mL of colchicine and propranolol for 60 min following tachyzoites addition was the most efficient method to inhibit tachyzoites penetration, indicating the efficacy rates of 80.20%±1.20 and 89.97%±1.30, respectively (p< .05). Based on the in vivo test, pretreatment with 2 mg/kg of colchicine one hour before tachyzoites injection had the best inhibitory effect (70.32%±4.07). Also, pretreatment with 2 mg/kg of propranolol 90 min before tachyzoites injection (78.54%±1.99) induced the best inhibitory effect (p< .05).

According to the results, colchicine and propranolol could inhibit tachyzoites entrance into nucleated cells in vitro and in vivo. In this study, the most efficient concentrations and times for using these substances were determined.