Silver nanoparticles (AgNP), due to antimicrobial properties, are widely used in medical applications and consumer products. Expansive use of AgNP in manufacturing raises the concern of effects following respiratory exposure in workers. Previous work in the laboratory has shown dose-dependent lung toxicity with inflammation and alterations in lung immune parameters in rodents. The goal of the current study is to characterize effects of AgNP for potential exacerbation/ attenuation of respiratory allergy in an ovalbumin (OVA)-induced allergy model in BALB/c mice. For range-finding (RF) studies, mice were exposed to physiological dispersion medium (DM), 6.1ug (LO), 18.2ug (ME), or 73ug (HI) AgNP. AgNP were 20 nm diameter with 0.3% wt polyvinylpovidone coating (NanoAmor, Inc.), were suspended and sonicated before exposures by pharyngeal aspiration (PA) on day 0. For RF studies assays were conducted on days 1, 10, and 29 post exposure-time points chosen to correspond with the allergy paradigm time course. Airway hyperreactivity was measured as PenH, bronchalveolar lavage (BAL) was performed on the whole lung, cells and fluid were retained for analysis of lung-associated injury and inflammation and phenotyping by flow cytometry, lymph nodes (LN) were harvested for enumeration and phenotyping. Changes in PenH did not occur with AgNP alone at any time point. Results indicated a dose-dependent injury and inflammation by day 10 which began to resolve by day 29. For the allergy model, DM and OVA served as controls and ME and HI were chosen for study. Animals received i.p. injections of OVA + aluminum hydroxide gel (alum) during the sensitization phase on days 1 and 10. To elicit an OVA-specific response, 2 PA challenges of OVA were given on days 19 and 29. Dose dependent increases in PenH, BAL and LN cell number were observed in mice exposed to AgNP over OVA controls. Results indicate potential for AgNP to exacerbate allergic response in the lung.
The Toxicologist. Society of Toxicology 53rd Annual Meeting and ToxExpo, March 23-27, 2014, Phonex, Arizona