Trans-cortical vessels in the mouse temporal bulla bone are a means to recruit myeloid cells in chronic otitis media and limit peripheral leukogram changes

We report trans-cortical vessels in the mouse temporal bone connect to the bulla mucosal vasculature and potentially represent a means to recruit myeloid cells directly into the inflamed bulla. The mutant mouse strains Junbo (MecomJbo/+) and Jeff (Fbxo11Jf/+) develop chronic otitis spontaneously; MecomJbo/+ mice have highly cellular neutrophil (90%) rich bulla exudates whereas Fbxo11Jf/+ mice have low cellularity serous effusions (5% neutrophils) indicating differing demand for neutrophil recruitment. However we found peripheral leukograms of MecomJbo/+ and Fbxo11Jf/+ mice are similar to their respective wild-type littermate controls with healthy bullae and infer preferential mobilization of myeloid cells from temporal bulla bone marrow may mitigate the need for a systemic inflammatory reaction. The cytokines, chemokines and haematopoietic factors found in the inflamed bulla represent candidate signalling molecules for myeloid cell mobilization from temporal bone marrow. The density of white blood cells in the bulla cavity is positively correlated with extent of mucosal thickening in MecomJbo/+, Fbxo11Jf/+, and EdaTa mice and is accompanied by changes in epithelial populations and bone remodelling. In MecomJbo/+ mice there was a positive correlation between bulla cavity WBC numbers and total bacterial load. The degree of inflammation varies between contralateral bullae and between mutant mice of different ages suggesting inflammation may wax and wane and may be re-initiated b...
Source: Frontiers in Genetics - Category: Genetics & Stem Cells Source Type: research