Uptake of Some Metallic Nanoparticles by, and their Impact on Pulmonary Macrophages in Vivo as Viewed by Optical, Atomic Force, and Transmission Electron Microscopy

Abstract

Optical microscopy (OM), semi-contact atomic force microscopy (sc-AFM), and transmission electron microscopy (TEM) were applied to examine cells in the broncho-alveolar lavage fluid (BALF) obtained from rats 24 hours after instillation of different metallic particles suspended in deionised water or of water without any particles. In a comparative experiment with iron oxide Fe 3 O 4 (magnetite) particles having a mean diameter of 10 nm, 50 nm or 1 μm, it was demonstrated that, given equal mass doses, nanoparticles (NPs) induce much more intensive recruitment of phagocytes with a much more significant shift toward neutrophil leukocytes (NL) count in the BALF cell population than micrometric particles do, this shift being an indirect but informative index of particle cytotoxicity for alveolar macrophages (AM). Judging by NL/AM ratio, this cytotoxicity diminishes in the sequence: 10 nm > 50 nm> 1 μm, while judging by OM counts of visible aggregated particles within AMs and NLs and by sc-AFM count of micro-invaginations on the surfaces of these cells, their avidity for particles decreases in the same succession. The same dependence of cell recruitment and of phagocytic activity on NP cytotoxicity was found when the NP diameters were quite similar (ca. 3.5-4.0 nm) but the cytotoxicity of one metal (in our experiment, nanosilver) was higher than that of another (nanogold). TEM pictures of AMs from rats administered the 10 nm magnetite testify to the ability of AMs to actively engulf single NPs and their small aggregates which then form larger conglomerates within fused phagosomes. Some of these large phagosomes lost their membrane, and so freed NPs came into close contact with the nuclear membrane and with mitochondrial membranes and cristae causing their marked damage.

Comparative in Vivo Assessment of Some Adverse Bioeffects of Equidimensional Gold and Silver Nanoparticles and the Attenuation of Nanosilver’s Effects with a Complex of Innocuous Bioprotectors

“…Table 1 presents the results of a comparative estimation of shifts in the BALF cell population in response to intratracheal instillation of gold NPs and silver nano- or microparticles carried out within the framework of the present study, in comparison with the earlier published results of a similar experiment with finer NPs of the same metals [5]. Rather than in parallel, these two experiments were carried out in different periods (2011 and 2012) and—what is especially important—with different background BALF cell counts (as can be seen from Table 1, all indices for control rats were higher in the second experiment as compared with the first one).…”

“…Our own pilot experiments involving intratracheal instillations of NG and NS suspensions have shown that NS provokes a substantially greater increase in the cell count of the bronchoalveolar lavage fluid (BALF), and, judging from the ratio of neutrophil leukocytes to alveolar macrophages in BALF, NS is more cytotoxic for alveolar macrophages than NG [5]. These newly obtained data, however, need to be reproduced, preferably in experiments with the same NG and NS samples that would be used for comparative assessment of systemic toxicity and genotoxicity.…”

Some inferences from in vivo experiments with metal and metal oxide nanoparticles: the pulmonary phagocytosis response, subchronic systemic toxicity and genotoxicity, regulatory proposals, searching for bioprotectors (a self-overview)

“…[1][2][3][4][5][6][7][8][9][10] We experimented with NPs of iron oxide Fe 3 O 4 (magnetite) having mean diameters 10 nm, 50 nm or 1 mcm, gold (4 nm or 50 nm), silver (4 nm, 49 nm or 1.1 mcm), copper oxide (20 nm or 340 nm), nickel oxide NiO (30 nm), and manganese oxide Mn 3 O 4 (32 nm). Keeping in mind the above mentioned theoretical premises of our research, we used purposefully prepared and accurately characterized NPs of pure metals or their oxides suspended in deionized water rather than commercial nanomaterials.…”

“…Indeed, although the mean diameter The TEM images ( Figure 8) also testify to the physiological endocytosis of NPs as opposed to their direct penetration through cell membrane by diffusion, which, above any doubts, is also possible. [4][5][6] When NPs are of given dimensions, the pulmonary phagocytosis response strongly depends on their chemical nature. For instance, as can be seen from Table 2, the total cell, NL and AM counts, and the macrophage count of the BALF increased under the impact of silver NPs more than it did under the impact of virtually equidimensional gold NPs.…”

“…During 2009-2014 our experimental work was focused on trying to find answers to these important questions. [1][2][3][4][5][6][7][8][9][10] Although in the vast nanotoxicological literature of the last decade studies concerned with the assessment of metal or metal-oxide NP toxicity are not at the top of the list, such publications are nevertheless quite numerous. To illustrate this, we may refer to several works devoted to NPs of the metals that were the subject-matter of our own studies considered below: iron oxide, [11][12][13][14][15][16][17][18][19][20] silver, gold, 24,[45][46][47][48][49][50][51][52][53][54][55][56][57][58] copper and copper oxide, 43,[59][60][61][62][63][64][65][66][67][68] nickel oxide, 65,…”