The effects of naris occlusion on mouse nasal turbinate development

Abstract

Unilateral naris occlusion, a standard method for causing odor deprivation, also alters airflow on both sides of the nasal cavity. We reasoned that manipulating airflow by occlusion could affect nasal turbinate development given the ubiquitous role of environmental stimuli in ontogenesis. To test this hypothesis, newborn mice received unilateral occlusion or sham surgery and were allowed to reach adulthood. Morphological measurements were then made of paraffin sections of the whole nasal cavity. Occlusion significantly affected the size, shape and position of turbinates. In particular, the nasoturbinate, the focus of our quantitative analysis, had a more delicate appearance on the occluded side relative to the open side. Occlusion also caused an increase in the width of the dorsal meatus within the non-occluded and occluded nasal fossae, compared with controls, and the position of most turbinates was altered. These results suggest that a mechanical stimulus from respiratory airflow is necessary for the normal morphological development of turbinates. To explore this idea, we estimated the mechanical forces on turbinates caused by airflow during normal respiration that would be absent as a result of occlusion. Magnetic resonance imaging scans were used to construct a three-dimensional model of the mouse nasal cavity that provided the input for a computational fluid dynamics simulation of nasal airflow. The simulation revealed maximum shear stress values for the walls of turbinates in the 1 Pa range, a magnitude that causes remodeling in other biological tissues. These observations raise the intriguing possibility that nasal turbinates develop partly under the control of respiratory mechanical forces.

The influence of nasal airflow on respiratory and olfactory epithelial distribution in felids

“…Recent research has shown that airflow may influence turbinal size and shape during development (Coppola et al, 2014), which is consistent with the results of the present study. Inferring epithelial surface area from CT data alone is difficult, but can be improved by taking into account nasal airflow patterns and the variability of OE distribution in different species.…”

“…4C) from the MRI data using the methodology of Craven and colleagues (Craven et al, 2007;Ranslow et al, 2014;Coppola et al, 2014). A high-fidelity, hexahedral-dominant computational mesh (Fig.…”

Ontogeny and Microanatomy of the Nasal Turbinals in Lemuriformes

“…If true, this implies that increasing postnatal complexity of the nasal turbinals is an epigenetic phenomenon relating to respiratory physiology and enlarging airways. A recent study by Coppola et al () revealed that experimental naris occlusion in newborn mice is associated with altered size and shape of turbinals. Additionally, airflow simulations of the altered nasal cavity are associated with high shear stress values in the nasal walls.…”

Climatic adaptation in human inferior nasal turbinate morphology: Evidence from Arctic and equatorial populations

“…As virtually all research indicates a predominant genetic basis for nasal morphology (Adhikari et al, ; Claes et al, ; Pickrell et al, ; Shaffer et al, ; Zaidi et al, ), we have largely interpreted the differences in turbinate morphology between our Arctic and equatorial samples within an implicit context of genetically‐mediated climatic adaptation. However, it is important to recognize that the turbinates do exhibit some degree of plasticity, with the capacity to remodel in response to biomechanical factors such as wind shear (Coppola, Craven, Seeger, & Weiler, ) and in relation to developmental or pathological changes in other areas of the nasal cavity (Berger, Hammel, Berger, Avraham, & Ophir, ; Egeli, Demirci, Yazýcý, & Harputluoglu, ; Grymer, Illum, & Hilberg, ; Hartman et al, ). Alternatively, recent research (Holton et al, ) has suggested that nasal components of the chondrocranium, including the turbinates, may influence the development of surrounding intramembranous‐derived nasal structures (e.g., maxillae, premaxillae, nasal bones) during ontogeny.…”