Comparative histological analysis of the alae nasi in French bulldogs with brachycephalic obstructive airway syndrome and unaffected non-brachycephalic dogs.

BACKGROUND

Brachycephalic dogs are characterised by a short and flat nose. This cranial conformation is associated with brachycephalic obstructive airway syndrome, a respiratory syndrome primarily characterised by stenotic nares, a hyperplastic soft palate and a hypoplastic trachea, among other malformations, with secondary abnormalities resulting in upper airway obstruction

METHODS

In this study, we aimed to characterise and compare the histological features of tissue samples harvested from the alae nasi of French bulldogs and non-brachycephalic dogs. Samples from the alae nasi of 11 French bulldogs and 13 non-brachycephalic dogs were collected. Four-μm-thick, paraffin-embedded sections were obtained from each tissue sample and mounted on glass slides, followed by staining with haematoxylin and eosin, periodic acid-Schiff and toluidine blue for histological examination.

RESULTS

The only variation observed between the samples obtained from French bulldogs and those obtained from non-brachycephalic dogs concerned the presence of cartilage in the specimens. Cartilage was absent in 10 of 11 French bulldogs but present in nine of 13 non-brachycephalic dogs; this difference was statistically significant (p < 0.05).

LIMITATIONS: The findings of this study need further validation in future prospective studies. It would be useful to examine the entire nostril wing, to include additional brachycephalic breeds, a larger number of subjects spanning a wider age range and degree of stenotic nares severity, a larger tissue sample, and a broadening of the control group to include dolichocephalic and mesaticephalic dogs.

CONCLUSION

This study found an absence of cartilage in French bulldog nare specimens compared to those from non-brachycephalic dogs. This absence of cartilage may contribute to brachycephalic obstructive airway syndrome, although histological examination of the entire wing of the nostrils is needed to confirm this hypothesis.