Time-course comparison of pulmonary inflammation induced by intratracheal instillation of four different nickel oxide nanoparticles in male Fischer rats

The pulmonary effects of nickel-containing nanoparticles: Cytotoxicity, genotoxicity, carcinogenicity, and their underlying mechanisms

With the exponential growth of the nanotechnology field, the global nanotechnology market is on an upward track with fast-growing jobs. Nickel (Ni)-containing nanoparticles (NPs), an important class of transition metal nanoparticles, have been extensively used in industrial and biomedical fields due to their unique nanostructural, physical, and chemical properties. Millions of people have been/are going to be exposed to Ni-containing NPs in occupational and non-occupational settings. Therefore, there are increasing concerns over the hazardous effects of Ni-containing NPs on health and the environment. The respiratory tract is a major portal of entry for Ni-containing NPs; thus, the adverse effects of Ni-containing NPs on the respiratory system, especially the lungs, have been a focus of scientific study. This review summarized previous studies, published before December 1, 2023, on cytotoxic, genotoxic, and carcinogenic effects of Ni-containing NPs on humans, lung cells in vitro, and rodent lungs in vivo, and the potential underlying mechanisms were also included. In addition, whether these adverse effects were induced by NPs themselves or Ni ions released from the NPs was also discussed. The extra-pulmonary effects of Ni-containing NPs were briefly mentioned. This review will provide us with a comprehensive view of the pulmonary effects of Ni-containing NPs and their underlying mechanisms, which will shed light on our future studies, including the urgency and necessity to produce engineering Ni-containing NPs with controlled and reduced toxicity, and also provide the scientific basis for developing nanoparticle exposure limits and policies.

Time‐course analysis of pulmonary inflammation induced by intratracheal instillation of nanosized crystalline silica particles in F344 rats

Crystalline silica is an important cause of serious pulmonary diseases, and its toxic potential is known to be associated with its surface electrical properties. However, in vivo data clarifying the relevance of silica's toxic potential, especially its long-term effects, remain insufficient. To investigate the contribution of physico-chemical property including surface potential on the hazard of nanocrystalline silica, we performed single intratracheal instillation testing using five different crystalline silicas in a rat model and assessed time-course changes in pulmonary inflammation, lung burden, and thoracic lymph node loads. Silica-nanoparticles were prepared from two commercial products (Min-U-Sil5 [MS5] and SIO07PB [SPB]) using three different pretreatments: centrifugation (C), grinding (G), and surface dissolving (D). The five types of silica particles-MS5, MS5_C, SPB_C, SPB_G, and SPB_D-were intratracheally instilled into male F344 rats at doses of 0 mg/kg (purified water), 0.22 mg/kg (SPB), and 0.67, 2, or 6 mg/kg (MS5). Bronchoalveolar lavage, a lung burden analysis, and histopathological examination were performed at 3, 28, and 91 days after instillation. Granuloma formation was present in MS5 group at 91 days after instillation, although granuloma formation was suppressed in MS5_C group, which had a smaller particle size. SPB_C induced severe and progressive inflammation and kinetic lung overload, whereas SPB_G and SPB_D induced only slight and transient acute inflammation. Our results support that in vivo toxic potential of nanosilica by intratracheal instillation may involve with surface electrical properties leading to prolonged effect and may not be dependent not only on surface properties but also on other physico-chemical properties.