Toxic effect of the titanium dioxide rutile form on the morphological characteristics of the immune system organs

Abstract

The aim. To study the effect of the rutile form of titanium dioxide upon its oral administration on the morphological and functional state of the organs of the immune system of rats. Materials and methods. In this work, using classical morphological approaches and specific markers: proliferation - Ki-67, PCNA, apoptosis - protein p53 and macrophages - CD68, which make it possible to adequately identify not only the cells themselves, but also their functional state, a study of the spleen and thymus of rats after oral administration (10 mg/kg animal body weight, 28 days) of a nanodispersed form of TiO2 (rutile form, 40-60 nm) obtained by diluting TiO2 powder in distilled water was carried out. Aggregation of nanoparticles was prevented by treatment of a suspension of nanodispersed TiO2 in an ultrasonic bath. Rats of the control group were orally administered with distilled water in the same volume. Results. With oral administration of the rutile form of nanodispersed TiO2, a moderate accidental involution of the thymus is observed, a reduction in the white pulp of the spleen, due to a decrease in the proliferative potential and an increase in apoptosis. The revealed morphofunctional changes in lymphoid organs can be interpreted from the standpoint of induced secondary immunodeficiency that develops against the background of exposure to rutile TiO2 NPs. Limitations. When studying the effect of titanium dioxide (rutile, 40-60 nm, 10 mg/kg of animal body weight) on the morphological characteristics of the immune defense organs, the sample size was 12 Wistar rats, the maximum duration of exposure was 28 days. Conclusion. The detected morphofunctional changes in the lymphoid organs can be interpreted from the position of induced secondary immunodeficiency, developing against the background of exposure to NPS TiO2 of the rutile modification.