Acute inhalation toxicity of manganese oxide nanoparticles

Abstract

Manganese oxides have been synthesized by the interaction of Mn 2+ and Mn in the presence of nanoreactors: cetyltrimethylammonium bromide micelles that were not present in the final product composition. The synthesized substance is investigated using scanning electron microscopy, X-ray diffraction analysis, dynamic light scattering, the Brunauer-Emmett-Teller method, and the method of Barrett-Joyner-Halenda. It is determined that the substance under examination is a filamentous nanometer-scale material with a cross-section size up to 100 nm. The acute inhalation toxicity study is performed according to the interstate standard using the method of acute-toxicity class determination (ATC method) (OECD, Test no. 436:2008, IDT). The ATC method allows us to see that synthesized nanosized manganese oxide has an acute toxicity property when inhaled as an aerosol. Upon 4-h exposure to Wistar rats weighing 190 ± 10g, CL 50 is 0.12 mg/L. The clinical picture of acute intoxication is characterized by irritation, neurotoxic effects, and respiratory depression. According to CL 50 (>0.05-0.5), mg/L criterion, synthesized nanosized manganese oxide belongs to hazard class 2 in accordance with Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

Toxicologic Characteristics of Nanodisperse Manganese Oxide: Physical-Chemical Properties, Biological Accumulation, and Morphological-Functional Properties at Various Exposure Types

“…Nerve fibers of brain tissue looked spongy and were unevenly colored, had fizzy contours, and focal prolapse of glial elements (Figure 6). Nanoparticle concentration in the inhalation chamber air at actual MnO 2 concentration equal to 0.472 ± 0.005 mg/dm 3 [15]. The results obtained in the course of the research indicate that the examined nanosized МnO 2 particles can cause neurotoxic effect and respiratory failure; the combination of these two factors could lead to the animals' death.…”

“…Scanning electron microscopy image of MnO 2 nanoparticles, electron microscopy with a high-resolution scanning microscope (3-10 nm, max magnification of 300,000X) S-3400 N (Hitachi, Japan) with energy dispersive X-ray attachment for microanalysis (Bruker, Germany) [15].…”

“…Disorders in neurons membranes functions can underlie the neurotoxic action mechanism; such disorders result from membranes lipid peroxidation which in its turn is caused by direct cytotoxic effect of nanoparticles determined for dopaminergic Figure 6. Cerebellum of a Wistar rat after acute inhalation exposure to nanodisperse MnO 2 aerosol at actual MnO 2 concentration in the inhalation chamber area equal to 0.029 ± 0.001 mg/dm 3 (painted with hematoxylin-eosin, ×400): А is cerebellum tissue without changes, green; B is ischemia focus (grave ischemic changes), edema (damage zone is outlined); С is motor neuron of cerebellum subcortex; and D is glia cells with pericellular space dilatation [15].…”

“…Nanoparticle concentration in the inhalation chamber air at actual MnO 2 concentration equal to 0.029 ± 0.001 mg/dm3 [15].…”

“…Nanodisperse MnO 2 : (a) nitrogen isotherm adsorption-desorption and (b) pore size distribution d (nm)[15].…”