Genotoxicity of Titanium Dioxide Nanoparticles using the Mouse Bone Marrow Micronucleus and Sperm Morphology Assays

Abstract

Titanium dioxide nanoparticles (TiO 2 -NPs) have recently been of public health and scientific concern due to their widespread use in industrial and household applications. However, there is limited information concerning its in vivocytogenotoxicity. In this study, the cytogenotoxic effects of TiO 2 -NPs on the somatic tissue using the mouse bone marrow micronucleus (MN) assay and on reproductive tissue using the mouse sperm morphology assay and testicular histopathology were investigated. Five concentrations of 9.38, 18.75, 37.50, 75.00 and 150.00 mg/kg bwt were administered intraperitoneally at 0.5 mL/mouse to mice for five and ten consecutive days in the MN assay; and for five consecutive days in the sperm morphology assay. Double distilled water and cyclophosphamide (20 mg/kg bwt) served as negative and positive controls, respectively. A significant (p<0.05) increase in MN was observed in bone marrow cells of treated mice at 37.50 mg/kg bwt concentration in the 5-day exposure and at all concentrations in the 10-day exposure. The sperm cells examined 5 and 10 weeks from the first day of exposure showed significant increase (p<0.05) in abnormal sperm cells at tested concentrations. Histopathologically, TiO 2 -NPs disrupted the normal cellular architecture of testicular tissues in exposed mice; as it caused severe lesions such as congestion of the interstitium oedema, vacuolation and necrosis. These suggest that the bone marrow and testicular cells may be potential targets for TiO 2 -NPs induced DNA damage and cytotoxicity in mice. This is of public health importance considering increasing exposure to TiO 2 -NPs in consumer products.