Fig. 2

Histological and immunohistochemical evaluation of the lung tissue after exposure to CuO nanomaterials. BALB/c mice were sensitized ip to OVA/Alum on day 1 and 10, and exposed repeatedly to 2.5, 10 or 40 μg/mouse of CuO nanomaterials dispersed in PBS with or without OVA by oropharyngeal aspiration after a 10-day recovery period. H&E-stained lung tissue of a a PBS-challenged control, b OVA-challenged, c PBS-challenged and 40 μg of core CuO-exposed, and d OVA-challenged and 40 μg of core CuO-exposed mouse. The presence of eosinophils in OVA-challenged mice and neutrophils accompanied with nuclear dust in CuO-treated mice were found. E, The number of CD3+, CD4+ and CD8+ T cells in the lung tissue. Images a-d are shown at × 400 magnification with a 50-μm scale bar. Arrows in the insets indicate the location of nuclear dust. Counts of T cell subtypes in e are shown as positive cells per high power field (HPF) with the highest number of cells marked on top of each plot. Columns and error bars represent mean values ± standard error of mean (SEM). Statistically significant differences between experimental groups and PBS-challenged control mice are marked with “*” whereas the ones between experimental groups and OVA-challenged control mice are marked with “•”. */•P < 0.05; ***/•••P < 0.001