Metal-containing nanoparticles as risk factors causing pathomorphological changes in internal organs tissues in an experiment

Given wide spread of nanomaterials, it seems vital to estimate and predict changes in internal organs tissues under exposure to metal-containing nanoparticles that are risk factors causing negative effects occurring in critical organs and systems. It requires revealing objective procedures that can be used to quantitatively assess risks of pathologic changes in tissues that at present have only qualitative properties. Our research goal was to quantitatively assess risks of lung diseases occurrence in rats exposed to metal-containing nanoparticles (exemplified by nano-sized CuO) using image analyzing procedures. We examined toxic effects produced by nano-disperse CuO (45.86 nm) under inhalation (a single and 14-day multiple) exposure and oral exposure (for 20 days); the experiment was performed on male Wistar rats (60 animals). Exposed animals were divided into 5 groups, 12 animals in each (group 1, a single inhalation exposure; group 2, multiple inhalation exposure; group 3, oral exposure; groups 4 and 5 were exposed to bi-distilled water in a similar way, via inhalation and orally). When analyzing tissue images, we estimated first-, second- and third-order elements. Statistical significance of differences was estimated with Mann-Whitney U-test. Quantitative risk assessment (R) was performed taking into account probability (p) and severity (q) of pathomorphological changes in tissues. We established that pathomorphological disorders might occur in lung tissue taking into account identification of all elements in all images for all experimental groups; the probability varied from 0.16 to 1.2. The total risk of lung diseases amounted to 1.0·10-3 (average risk) under single inhalation exposure to a concentration equal to 0.001СL50; multiple inhalation exposure, 8.1·10-3 (high risk, oral exposure to a dose equal to 0.1LD50, 2.5·10- 2(high risk). Therefore, image analysis allows quantitatively assessing risks of diseases in critical organs and systems caused by exposure to metal-containing nanoparticles.