Effect of titanium dioxide nanoparticles on the cardiovascular system after oral administration

Titanium dioxide nanoparticles (TiO 2 NPs) have been widely used in various consumer products, especially food and personal care products. Compared to the well-characterized adverse cardiovascular effect of inhaled ambient ultrafine particles, research on the health response to orally administrated TiO 2 NPs is still limited. In our study, we performed an in vivo study in Sprague-Dawley rats to understand the cardiovascular effect of TiO 2 NPs after oral intake. After daily gastrointestinal administration of TiO 2 NPs at 0, 2, 10, 50   mg/kg for 30 and 90 days, heart rate (HR), blood pressure, blood biochemical parameters and histopathology of cardiac tissues was assessed to quantify cardiovascular damage. Mild and temporary reduction of HR and systolic blood pressure as well as an increase of diastolic blood pressure was observed after daily oral administration of TiO 2 NPs for 30 days. Injury of cardiac function was observed after daily oral administration of TiO 2 NPs for 90 days as reflected in decreased activities of lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (HBDH) and creatine kinase (CK). Increased white blood cells count (WBC) and granulocytes (GRN) in blood as well as increased concentrations of tumor necrosis factor α (TNF α) and interleukin 6 (IL-6) in the serum indicated inflammatory response initiated by TiO 2 NPs exposure. It was hypothesize that cardiac damage and inflammatory response are the possible mechanisms of the adverse cardiovascular effects induced by orally administrated TiO 2 NPs. Data from our study suggested that even at low dose of TiO 2 NPs can induce adverse cardiovascular effects after 30 days or 90 days of oral exposure, thus warranting concern for the dietary intake of TiO 2 NPs for consumers.