Nano-titanium dioxide induced cardiac injury in rat under oxidative stress

Heart diseases, which are related to oxidative stress (OS), negatively affect millions of people from kids to the elderly. Titanium dioxide (TiO₂) has widespread applications in our daily life, especially nanoscale TiO₂. Compared to the high risk of particulate matter (≤2.5μm) in air to heart disease patients, related research of TiO₂ on diseased body is still unknown, which suggest us to explore the potential effects of nanoscale and microscale TiO₂ to heart under OS conditions. Here, we used alloxan to induce OS conditions in rat, and investigated the response of heart tissue to TiO₂ in healthy and alloxan treated rats. Compared with NMs treatment only, the synergistic interaction between OS conditions and nano-TiO₂ significantly reduced the heart-related function indexes, inducing pathological changes of myocardium with significantly increased levels of cardiac troponin I and creatine kinase-MB. In contrast with the void response of micro-TiO₂ to heart functions in alloxan treated rats, aggravation of OS conditions might play an important role in cardiac injury after alloxan and nano-TiO₂ dual exposure. Our results demonstrated that OS conditions enhanced the adverse effects of nano-TiO₂ to heart, suggesting that the use of NMs in stressed conditions (e.g., drug delivery) needs to be carefully monitored.