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Information × Registration Number 0214U001628, 0111U000771 , R & D reports Title To develop metodical approaches to comparative studying organospecific lung toxicity and general toxic effects of nanoparticles (on the example of amorphous silicon, SiO2) popup.stage_title Head Stezhka Vasiliy Ananievich, Registration Date 31-03-2014 Organization State Institution "Institute for Occupational Health of the Academy of Medical Scieces of Ukraine" popup.description2 The dependence of the biological effect of nanopartilces (NP) of highly disperse amorphous silica, received by the pyrogenic technology with SiCI4 alloying in hydrogen-oxygen flame of three dimensions of the following types: A50 (mean size of NP - 87 nm, specific surface square - 39 m2/g), A100 (mean size of NP - 38 nm, specific surface square - 81 m2/g), A300 ( mean size of NP - 9 nm, specific surface square - 303 m2/g) on Vistar male rats after a single intratracheal instillation as a dispersion in the physiological solution on their size, surface square and the mass dose of a substance was studied. For the first time an original author's approach to standardization of NP doses, used for intratracheal instillation to rats was proposed according to: 1) the surface square in the calculation 0,25 m2, providing the direct contact with NP, taking into account the spherical form and the square of the alveolar surface in a rat with body mass 200 g (0,5 m2) and from 25% alveoli surface square; 2) by the number of NP, which have contact with one cell in the lungs alveoli surface (1000 NP/1 cell, 3,0x10x11 NP/rat); 3) by the substance mass (25 mg/rat). All NP doses, used for intratracheal instillation were characterized by three criteria: square surface, their number in the dose and by the substance mass in the dose. By the results of electronic microscopic and special spectral studies of the bronchoalveolar lavage there has been received a direct proof on the delay in the elimination of the certain part of intratracheally instillated standard NP doses from the alveolar epithelia lining in the inner medium of the rat body. The dynamic studies of the morphofunctional state of the lungs tissue, intratracheal lymphatic nodes, inner organs (heart, brain, liver, kidneys, thymus, spleen, adrenal glands) by the assessment of prooxidant - antioxidant equilibrium in the blood plasma and tissue homogenates of lungs, heart, brain, liver, by the blood cell reactions (erythrocyte, leukocyte-thrombocyte system, leukogram) and activity of intracellular enzymes (succinatedehydrogenase, myeloperoxidase) in the subpopulations of blood leucocytes, proved the delay of elimination of instillated NP from lungs through blood vessels and lymphatic drainage into the internal environment of the rat body by the end of the experiment (4 months). Based on the conducted complex morphological, biochemical, hematological and cytochemical studies of the peculiarities of the biological effect of NP of high disperse amorphous silica in all standardized doses after a single intratracheal instillation the presence of a significant organospecific damaging effect in them for lungs and the general toxic effect on rats. According to the majority of the results of the conducted studies the most damaging action on rats was recorded for NP of 9 nm and 38 nm, as compared with the size 87 nm. NP of high disperse amorphous silica, types A50, A100, A300 in the dose standardized by the substance mass (25 mg/rat) were biologically more aggressive than particles of the dust of the Lyuberetsky quarz PK-3 with the size 24,0±0,6 mkm. Morphofunctional and biochemical studies of peculiarities of the effect of NP of high disperse amorphous silica of different sizes (9 nm, 38 nm, 87 nm) and particles of the dust of Lyuberetsky quarz PK-3 with the size 24.0+0,6 mkm on the brain tissue allow us to confirm that irrespective of sizes and doses, both by the substance mass and the surface square and by the number of NP, they can penetrate through the hematoencephalic barrier and cause a damaging effect on neurocytes. In the delayed period (in 9 months) after a single intratracheal instillation of NP of high disperse amorphous silica to rats in all doses it was found a more expressed action on the lungs tissue, being of a specific character (availability of malignant growth) in NP of a small size and low doses, both by the substance mass and by the surface square and their number. Unlike widely known results of epidemiological studies, the results of the conducted complex morphological, biochemical, haematological and cytochemical experimental studies on peculiarities of the biological effect of three types of NP of high disperse amorphous silica, different by their size, after intratracheal instillation to rats, do not confirm the regularity "exposure-dose-response" on the body, as they have exerted more specific and heavy damaging effects on the body in lower doses by the criteria of the surface square, their number and the substance mass. According to the results of the revealed biological effects on the rat body after intratracheal instillation of the studied NP of high disperse amorphous silica, a conclusion can be made, that they can be classified as such representing a high degree of a potential hazard. Product Description popup.authors Діденко М.М. Стежка В.А. popup.nrat_date 2020-04-02 Close