Figure 2.

Bacterial induction of inflammation in sinonasal mucosa was partially mediated by neutrophils. Histological sections treated with hematoxylin and eosin (H&E) stain revealed sinonasal mucosa with neutrophilic inflammation that was most pronounced at 24 h post-infection. P. aeruginosa LESB58 was inoculated dropwise in the left naris of C57Bl/6 mice (~10⁶ CFU) providing a within-subject control in the right naris. (A) Focal neutrophil infiltration (30-40x more neutrophils per high power field) was observed at a 4 mm deep cross-section of the nasal cavity. Sinus secretions (mucus) with admixed cells were most abundant at 24-h post-infection. (B, C) Select areas of the field were expanded for visualization of a) neutrophilic inflammation and b) mucus secreting cells. Abbreviations used: DM, dorsal meatus; NT, nasoturbinate; S, septum.