Effects of Multi-Generational Soft Diet Consumption on Mouse Craniofacial Morphology.

Mohamed G Hassan,Timothy C Cox,Andrew H Jheon,Harjot Kaler,Nathan Young,Bin Zhang

doi:10.3389/fphys.2020.00783

Abstract

Variations in craniofacial morphology may arise as a result of adaptation to different environmental factors such as soft diet (SD), which lessens functional masticatory load. Prior studies have shown that changes in the masticatory muscle function associated with a switch to short-term SD led to changes in craniofacial morphology and alveolar bone architecture. However, the long-term effects of SD and the associated adaptive changes in craniofacial shape are unclear. Our novel study set out to profile prospective skull changes in mice fed with SDs over multiple generations using three-dimensional (3D) geometric morphometric analysis (GMA). Our results revealed that short-term SD consumption led to a significant decrease in craniofacial size, along with numerous shape changes. Long-term SD consumption over 15 continuous generations was not associated with changes in craniofacial size; however, shape analysis revealed mice with shortened crania and mandibles in the anteroposterior dimension, as well as relative widening in the transverse dimension compared to the average shape of all mice analyzed in our study. Moreover, changes in shape and size associated with different functional loads appeared to be independent – shape changes persisted after diets were switched for one generation, whereas size decreased after one generation and then returned to baseline size. Our study is the first to study the role of prolonged, multi-generational SD consumption in the determination of craniofacial size and shape.

Highlights

Can exclusive and prolonged consumption of soft diets (SDs) alter our and our offsprings’ craniofacial morphology? Human skulls have undergone morphological transformations over centuries with changes being most pronounced in areas associated with masticatory muscle attachments (Jantz, 2001; Godde, 2015; Manthey et al, 2017)
Prolonged SD did not affect the size of the cranium and mandible but shape changes, such as widening in the transverse dimension and decrease in the anteroposterior dimension of both the cranium and mandible were noted
Our study is the first to analyze mice on prolonged, multi-generational SD to determine the effects of diet consistency on craniofacial form

Summary

Introduction

Can exclusive and prolonged consumption of soft diets (SDs) alter our and our offsprings’ craniofacial morphology? Human skulls have undergone morphological transformations over centuries with changes being most pronounced in areas associated with masticatory muscle attachments (Jantz, 2001; Godde, 2015; Manthey et al, 2017). Mandibles showed shorter alveolar processes, smaller coronoid and gonial processes, and extruded molars compared to control mice fed with a hard diet (HD) (Odman et al, 2008; Mavropoulos et al, 2010; Anderson et al, 2014) All of these experiments were conducted over a single generation using different two-dimensional (2D) measurements (Kiliaridis et al, 1985; Bresin, 2001; Mavropoulos et al, 2004; Enomoto et al, 2010; Guerreiro et al, 2013)

Methods

Results

Conclusion