Study of potential toxicity of zinc and its oxide nanoparticles on blood parameters, morphological and functional state of liver and element status of pregnant rats and fetus

Nanoparticles of zinc (Zn NPs) and zinc oxide (ZnO NPs) are considered as materials of low toxicity, as Zn is the most important trace element in human body usually found in food and used as a food additive. Currently, there is a serious lack of information about the potential dangers of nanomaterials (NMs) for mammals, and particularly for human. Moreover, there is not enough information about their potential hazard for reproductive health. The aim of this study is to investigate the potential negative effects of positively charged 90 and 95 nm nanoparticles of zinc (Zn NPs) and zinc oxide (ZnO NPs) on metabolic processes during pregnancy according to morphological and biochemical blood indices, morphofunctional structure of liver and element status in Wistar rats and fetuses. Blood was collected from 21-day old animals. Of blood morphological indices, concentration of erythrocytes (1012/l), white blood cells (109/l), hemoglobin (g/l), hematocrit (%) was estimated. In blood serum ALT (U/l), AST (U/l) and LDH (U/l) activity was assessed. Tissue samples were analyzed on a mass spectrometer Elan 9000 and atomic emission spectrometer Optima 2000 V (Perkin Elmer, USA). We did not observe embryo-fetal pathology in rats in the experiment. The concentration of red blood cells and hemoglobin increased when Zn NPs injected. ZnO NPs application led to the development of mild leukocytosis. Increasing activity of enzymes (ALT, AST, LDH) demonstrates the destructive process in hepatocytes of mother rats, which depends directly on the dose and type of the nanoparticles. Generally, the blood parameters confirm a potentially hepatotoxic effect of Zn NPs and ZnO NPs which was shown histologically. Microstructural changes of liver tissue (degeneration and cytolysis along with regeneration and functional activation of the body) may be considered as compensatory (adaptive) response to the toxic effects of the nanoparticles. According to the severity of these phenomena and given comparable doses, the ZnO NPs can be attributed to more toxic NPs than Zn NPs. Zn NPs and ZnO NPs did not lead to critical changes in the pool of macro- and microelements and Zn level in liver of mother rats and fetal tissues. There was an accumulation of essential elements, though it had no notable influence on the course and outcome of pregnancy in the rats. The most expressed biological effect of nanoparticles was observed in the rats at the maximum doses of Zn NPs and ZnO NPs.