High-fat diet increases labial groove formation in maxillary incisors and is related to aging in C57BL/6 mice

Objectives: The aim of this study was to explore the relationship between the consumption of a high-fat diet and aging-dependent formation of maxillary incisor grooves in C57BL/6 mice, and to identify putative maxillary incisor groove-related genes. Methods: We fed 2-month-old and 16-month-old C57BL/6 mice on either a chow diet or a high-fat diet for three months and observed changes in maxillary incisor grooves. We examined tissue sections of the maxillary incisors with grooves and carried out transcriptome analysis of the apical tissue fragments of maxillary incisors with/without grooves. Results: Consumption of a high-fat diet for three months resulted in significant increases in both body weight and the number of incisor grooves. Both the number and frequency of incisor grooves increased in an age-dependent manner from 26 to 28 months, during which time an additional groove appeared. There was abnormal differentiation and apoptosis of ameloblasts on the labial surface at the grooves of the maxillary incisors. Transcriptome analysis identified 23 genes as being specific to 24-month-old mice; these included several genes related to apoptosis and cell differentiation. Conclusions: The study findings indicate that, in C57BL/6 mice, consumption of a high-fat diet increases labial groove formation in maxillary incisors, which is related to aging of the tissue stem cells in the apical root end of the teeth. (C) 2019 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.