Rats were exposed by inhalation to filtered air or to a low (100 ug/m3 using a commercial antimicrobial product [20 mg/L silver]) or high (1000 ug/m3 using a suspension [200 mg/L silver] synthesized to have a similar size distribution) concentration of silver nanoparticles for 5 h. Resultant lung burdens were by (0, 1.4, and 14.0) ug of silver per rat after exposure to the filtered air, low, and high doses respectively. At 1 d and 7 d post-exposure, the following parameters were monitored: pulmonary inflammation, lung cell toxicity, alveolar air / blood barrier damage, alveolar macrophage activity, blood cell differentials, responsiveness of the tail artery to vasoconstrictor or vasodilatory agents, and heart rate and blood pressure in response to isoproterenol or norepinephrine, respectively. In general, changes in pulmonary or cardiovascular parameters were absent or non-significant either 1 d or 7 d post-exposure with the exceptions of an increase in blood monocytes 1 d after the high dose silver exposure, and a decrease dilation of the tail artery in response to acetylcholine as well as an increased heart rate in response to isoproterenol 1 day after low dose silver exposure. Therefore, it is concluded that short-term inhalation of nano silver does not cause substantial acute toxicity.
Citation: Journal of Toxicology and Environmental Health-Part A-Current Issues
Pub Type: Journals