A model of chronic, transmissible Otitis Media in mice
Fig 2
Histopathology of mouse nasal cavity and middle ears on Bordetella pseudohinzii colonization.
Histopathology analyses conducted on C57BL/6J mice inoculated with 7,500 CFU of B. pseudohinzii delivered in 25 μl of PBS. Groups of infected mice (n = 6) were sacrificed on 3, 14, 28 and 123- days post inoculation (DPI). (A-D) Coronal sections of the nasal cavity of C57BL/6J mice stained with Hematoxylin and Eosin (HE) stain. 3 DPI. Image of nasal meatus showing small amounts of exudate at the frontonasal sinus (arrow). Scale bar = 500 μm. B) Higher magnification of Fig A (dashed rectangle) showing neutrophils embedded in pale basophilic mucopurulent exudate (arrow). Scale bar = 100 μm. C) 7 DPI. Image of nasal meatus with mild amounts of exudate (asterisk) and a thin basophilic, film-like layer extending throughout the nasal meatus (arrows and inset). Scale bar = 500 μm; Inset Scale bar = 10 μm. D) Higher magnification of Fig C, (dashed rectangle), showing mild amounts of neutrophils embedded in pale basophilic material (arrow). Scale bar = 100 μm. Abbreviations: Nasal meatus (NM); Olfactory bulb (OB); Nasopharynx (NP). (E-J) HE stained transverse sections through the middle ear of C57BL/6J mice controls (E, F) and infected with Bordetella pseudohinzii (G-J). E) 3 DPI showing Eustachian tube (long arrow), round window membrane (short arrow), and tympanic membrane (arrowheads). Scale bar = 500 μm. F) Higher magnification of E, (dashed rectangle area), showing the middle ear tympanic bulla and thin layer of ciliated epithelia (mucoperiosteum), overlying a thin lamina propria (arrowheads). Scale bar = 50 μm. G) 14 DPI showing large accumulation of exudate extending from Eustachian tube (long arrow), tympanic membrane (arrowheads), middle ear bones (asterisk), and round window (short arrow). Scale bar = 500 μm. H) Higher magnification of G, (dashed rectangle), Middle ear and tympanic bulla showing diffusely hypercellular mucoperiosteum (arrowheads) and hypertrophic mesenchymal cells (arrow) covering the lamellar bone (LM). Scale bar = 50 μm. Inset: Gram-negative (red) bacteria (asterisk) attached to cilia of the mucoperiosteum. Gram stain. Scale bar = 10 μm. I) 28 DPI showing moderate amounts of exudate in the middle ear and adjacent structures. Arrowhead points to the tympanic membrane, and arrow points to the mucoperiosteum. Scale bar = 500 μm. J) Higher magnification of Fig. I, (dashed rectangle), showing middle ear and tympanic bulla showing hypercellular mucoperiosteum (arrowhead) and lymphoid tissue formation (arrow). Scale bar = 50 μm. Abbreviations: External auditory meatus (EAM); Middle Ear (ME); Cochlea (Co); Brain Stem (BS); Lamellar bone (LB); Bone marrow (BM). (K-P) HE stained transverse sections through the middle ear of C57BL/6J mice 123 DPI with Bordetella pseudohinzii. K) Image shows focal granulomatous inflammation about the round window (arrowhead) and malleolus (asterisk). Tympanic membrane (arrow). Scale bar = 500 μm. L) Higher magnification of K, (dashed rectangle area), showing the round window with an area of granulomatous inflammation that contains cholesterol clefts (arrow) mixed with macrophages and neutrophils. Scale bar = 50 μm.