Silica nanoparticles (SNPs) are widely used in many scientific and industrial fields despite the lack of proper evaluation of their potential toxicity. This study examined the effects of acute exposure to SNPs, either alone or in conjunction with ovalbumin (OVA), by studying the respiratory systems in exposed mouse models. Three types of SNPs were used: spherical SNPs (S-SNPs), mesoporous SNPs (M-SNPs), and PEGylated SNPs (P-SNPs). In the acute SNP exposure model performed, 6-week-old BALB/c female mice were intranasally inoculated with SNPs for 3 consecutive days. In the OVA/SNPs asthma model, the mice were sensitized two times via the peritoneal route with OVA. Additionally, the mice endured OVA with or without SNP challenges intranasally. Acute SNP exposure induced significant airway inflammation and airway hyper-responsiveness, particularly in the S-SNP group. In OVA/SNPs asthma models, OVA with SNP-treated group showed significant airway inflammation, more than those treated with only OVA and without SNPs. In these models, the P-SNP group induced lower levels of inflammation on airways than both the S-SNP or M-SNP groups. Interleukin (IL)-5, IL-13, IL-1beta and interferon-gamma levels correlated with airway inflammation in the tested models, without statistical significance. In the mouse models studied, increased airway inflammation was associated with acute SNPs exposure, whether exposed solely to SNPs or SNPs in conjunction with OVA. P-SNPs appear to be relatively safer for clinical use than S-SNPs and M-SNPs, as determined by lower observed toxicity and airway system inflammation.
Animals ; Asthma/*chemically induced/pathology ; Female ; Inflammation/*chemically induced/pathology ; Interferon-gamma/analysis ; Interleukins/analysis ; Lung/drug effects/*pathology ; Mice, Inbred BALB C ; Nanoparticles/*adverse effects/chemistry ; Ovalbumin/adverse effects ; Polyethylene Glycols/adverse effects/chemistry ; Silicon Dioxide/*adverse effects/chemistry ; Surface Properties

OBJECTIVETo investigate the pharmacological effect of Nyctanthes arbortristis (NAT) leaf extract in the prevention of lung injury induced by silica particles.

METHODLung injury was induced in Swiss mice through inhalation exposure to silica particles (< 5 mu) using a Flow Past Nose Only Inhalation Chamber at the rate of -10 mg/m3 respirable mass for 5 h. Lung bronchoalveolar lavage (BAL) fluid collected between 48 and 72 h was subjected to protein profiling by electrophoresis and cytokine evaluation by solid phase sandwich ELISA. Lung histopathology was performed to evaluate lung injury.

RESULTSInhalation of silica increased the level of tumor necrosis factor-alpha (TNF-alpha), and of the 66 and 63 kDa peptides in the BAL fluid in comparison to sham-treated control. Pre-treatment of silica exposed mice with NAT leaf extract significantly prevented the accumulation of TNF-alpha in the BAL fluid, but the 66 and 63 kDa peptides remained unchanged. The extract was also effective in the prevention of silica-induced early fibrogenic reactions like congestion, edema and infiltration of nucleated cells in the interstitial alveolar spaces, and thickening of alveolar septa in mouse lung.

CONCLUSIONNAT leaf extract helps in bypassing silica induced initial lung injury in mice.

Administration, Oral ; Animals ; Bronchoalveolar Lavage Fluid ; Disease Models, Animal ; Enzyme-Linked Immunosorbent Assay ; Inhalation Exposure ; Male ; Mice ; Oleaceae ; chemistry ; Phytotherapy ; Plant Extracts ; pharmacology ; Pulmonary Fibrosis ; etiology ; prevention & control ; veterinary ; Silicon Dioxide ; adverse effects ; Silicosis ; prevention & control ; veterinary