The Cytotoxic and Immunomodulatory Effects of Titanium Dioxide Nanoparticles and Sargassum oligocystum on Toxoplasma gondii In Vitro and In Vivo

Objective: This study was undertaken to evaluate the effect of titanium dioxide (TiO2) nanoparticles (NPs) and methanolic extract of Persian Gulf brown algae (Sargassum oligocystum) on the growth and cell death of T. gondii tachyzoites in vitro and in vivo. Methods: Six- to eight-week-old female BALB/c mice (n = 28) were used for the treatment experiment and infected with 10⁵ T. gondii tachyzoites. Four days after treatment, IFN-γ and the levels of splenic lymphocyte proliferation were measured. All the groups were challenged with T. gondii, and the survival rate of experimental mice was assessed. The effects of TiO2NPs and S. oligocystum on the proliferation of T. gondii were evaluated by MTT and annexin V staining in vitro. Results: Based on the results, the combination of S. oligocystum extract and TiO2NPs exhibited a more cytotoxic effect compared to their use separately. The results of the challenge test also revealed that mice which received combined treatment had the highest life time expectancy than those receiving the treatment alone. Conclusion: The simultaneous use of immunomodulatory compounds for the stimulation of the immune system as well as S. oligocystum and TiO2NPs with antiparasitic activity can be promising to develop an effective drug for the treatment of toxoplasmosis.