Effect of high fat diet and excessive compressive mechanical force on pathologic changes of temporomandibular joint

Jing Du,Shuang Lin,Li Mei,Huang Li,Juan Wen,Ren Yang,Qian Jiang

doi:10.1038/s41598-020-74326-z

Abstract

The aim of this study was to investigate the effect of high fat diet and excessive compressive mechanical force on temporomandibular joint. In vivo, a mouse model of temporomandibular joint compressive loading device was used. A high fat diet mouse model and a combined mouse model intraperitoneally treated with or without simvastatin were used in the study. The pathological changes of mandibular condylar cartilage were assessed by Safranin-O staining. The IL-1β, MMP-3, leptin expression changes in the cartilage were detected by immunohistochemistry. In vitro, the mandibular condylar chondrocytes were treated with or without L-1β and simvastatin. The mRNA expression level of matrix MMPs and leptin were assessed. Both excessive compressive mechanical force and high fat diet induced obesity caused TMJ osteoarthritis-like changes and increased expression of IL-1β, MMP-3, and leptin. These pathological changes were much more serious when the two interventions were exerted together, while simvastatin could obviously alleviate these changes. The mRNA expression of MMP-3, MMP-13, and leptin increased in the IL-1β treated chondrocytes treated with IL-1β, and decreased with simvastatin treatment. The development of temporomandibular joint pathological changes could be caused by the excessive compressive mechanical force and high fat diet induced obesity.

Highlights

The aim of this study was to investigate the effect of high fat diet and excessive compressive mechanical force on temporomandibular joint
After 24 h of IL-1β treatment on the condylar chondrocytes, the mRNA expression level of cartilage matrix degradation enzyme, MMP-3 and MMP-13, increased by 170% (Fig. 1A) and 130% (Fig. 1B) respectively, and the mRNA expression of leptin was up-regulated by 150% compared with Control (Fig. 1C)
The mRNA expression of MMP-3 and MMP-13 in the IL-1β + ST group decreased by 37% (Fig. 1A) and 48% (Fig. 1B) respectively compared with the IL-1β group

Summary

Introduction

The aim of this study was to investigate the effect of high fat diet and excessive compressive mechanical force on temporomandibular joint. The mRNA expression level of matrix MMPs and leptin were assessed Both excessive compressive mechanical force and high fat diet induced obesity caused TMJ osteoarthritis-like changes and increased expression of IL-1β, MMP3, and leptin. These pathological changes were much more serious when the two interventions were exerted together, while simvastatin could obviously alleviate these changes. Even though pathological changes in keen joint are similar to TMJOA, unlike hyaline cartilage in keen joint, fibrous cartilage in TMJ may have different pathogenesis when OA appears Most of those previous studies of osteoarthritis were carried out on the knee joint, the association of obesity and excessive compressive mechanical force with TMJOA is still poorly understood. For TMJOA caused by excessive compressive mechanical force and high fat diet, the therapeutic role of statins remains unclear

Objectives

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Results

Conclusion