title: Morphological differences of the carotid body among C57/BL6 (B6), A/J, and CSS B6A1 mouse strains.
abstract: The C57/BL6 (B6) mouse strain exhibits post-hypoxic frequency decline and periodic breathing, as well as greater amount of irregular breathing during rest in comparison to the A/J and to the B6a1, a chromosomal substitution strain whereby the A/J chromosome 1 is bred onto the B6 background (Han et al., 2002; Yamauchi et al., 2008a,b). The hypothesis was that morphological differences in the carotid body would associate with such trait variations. After confirming strain differences in post-hypoxic ventilatory behavior, histological examination (n=8 in each group) using hematoxylin and eosin (H&E) staining revealed equivalent, well-defined tissue structure at the bifurcation of the carotid arteries, an active secretory parenchyma (type I cells) from the supportive stromal tissue, and clustering of type I cells in all three strains. Tyrosine hydroxylase (TH) immunohistochemical staining revealed a typical organization of type I cells and neurovascular components into glomeruli in all three strains. Image analysis from 5 μm sections from each strain generated a series of cytological metrics. The percent carotid body composition of TH+ type I cells in the A/J, B6 and B6a1 was 20±4%, 39±3%, and 44±3%, respectively (p=0.00004). However, cellular organization in terms of density and ultrastructure in the B6a1 is more similar to the B6 than to the A/J. These findings indicate that genetic mechanisms that produce strain differences in ventilatory function do not associate with carotid body structure or tyrosine hydroxylase morphology, and that A/J chromosome 1 does not contribute much to B6 carotid body morphology.
authors.affiliation: Department of Pulmonary, Critical Care, and Sleep Medicine, Case Western Reserve University, Cleveland, OH 44106, United States.
authors.forename: Sam
authors.initials: S
authors.lastname: Chai
authors.forename: Carl B
authors.initials: CB
authors.lastname: Gillombardo
authors.forename: Lucas
authors.initials: L
authors.lastname: Donovan
authors.forename: Kingman P
authors.initials: KP
authors.lastname: Strohl
mesh_terms: D000818:Animals; D002344:Carotid Body / Q000033:anatomy & histology* / Q000378:metabolism*; D000860:Hypoxia / Q000473:pathology / Q000503:physiopathology; D007658:Ketone Oxidoreductases / Q000378:metabolism; D051379:Mice; D008805:Mice, Inbred A; D008810:Mice, Inbred C57BL; D019001:Nitric Oxide Synthase / Q000378:metabolism; D012119:Respiration; D013045:Species Specificity; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D014841:von Willebrand Factor; D019001:Nitric Oxide Synthase; D014446:Tyrosine 3-Monooxygenase; D007658:Ketone Oxidoreductases; C053164:pyruvate dehydrogenase (NADP+)