Subchronic Inhalation Toxicity of Silver Nanoparticles

TLDR

Target organs for silver nanoparticles were considered to be the lungs and liver in male and female rats. The study exposed 40 Sprague‑Dawley rats to silver nanoparticles (18–19 nm) at low, middle, and high concentrations for 13 weeks, monitoring clinical signs, body weight, pulmonary function, and performing necropsy, hematology, and organ weight analyses. Dose‑dependent liver bile‑duct hyperplasia and pulmonary lesions—including inflammatory infiltrates, chronic alveolar inflammation, and granulomas—were observed, and the study suggested no observable adverse effect level at 100 μg/m³.

Abstract

The subchronic inhalation toxicity of silver nanoparticles was studied in Sprague-Dawley rats. Eight-week-old rats, weighing approximately 253.2 g (males) and 162.6 g (females), were divided into four groups (10 rats in each group): fresh-air control, low dose (0.6 × 106 particle/cm3, 49 μg/m3), middle dose (1.4 × 106 particle/cm3, 133 μg/m3), and high dose (3.0 × 106 particle/cm3, 515 μg/m3). The animals were exposed to silver nanoparticles (average diameter 18–19 nm) for 6 h/day, 5 days/week, for 13 weeks in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and pulmonary function tests were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and the organ weights were measured. Bile-duct hyperplasia in the liver increased dose dependently in both the male and female rats. Histopathological examinations indicated dose-dependent increases in lesions related to silver nanoparticle exposure, including mixed inflammatory cell infiltrate, chronic alveolar inflammation, and small granulomatous lesions. Target organs for silver nanoparticles were considered to be the lungs and liver in the male and female rats. No observable adverse effect level of 100 μg/m3 is suggested from the experiments.