Structural features of the articular disc of the rat temporomandibular joint: Fibrocartilage or dense fibrous lamina?

IF 2.3 Q1 DENTISTRY, ORAL SURGERY & MEDICINE
Shunichi Shibata , Masami Takahashi , Toru Shibui , Yuri Seki-Kishimoto , Masaki Takechi , Kazuharu Irie
{"title":"Structural features of the articular disc of the rat temporomandibular joint: Fibrocartilage or dense fibrous lamina?","authors":"Shunichi Shibata ,&nbsp;Masami Takahashi ,&nbsp;Toru Shibui ,&nbsp;Yuri Seki-Kishimoto ,&nbsp;Masaki Takechi ,&nbsp;Kazuharu Irie","doi":"10.1016/j.job.2025.100694","DOIUrl":null,"url":null,"abstract":"<div><h3>Objectives</h3><div>The structure of the temporomandibular joint (TMJ disc) articular disc as a dense fibrous lamina or fibrocartilage is an ongoing debate. To clarify this, we investigated TMJ disc cells in 3- to 20-week-old rats from the perspectives of general histology, ultrastructure, immunohistochemistry, and <em>in situ</em> hybridization.</div></div><div><h3>Methods</h3><div>Sections from paraffin-embedded TMJ discs were immunohistochemically stained using antibodies against aggrecan and collagen type II. Expression of <em>Acan</em> and <em>Col2a1</em> mRNA was analyzed by <em>in situ</em> hybridization using antisense cRNA probes. Other samples were analyzed by transmission electron microscopy.</div></div><div><h3>Results</h3><div>Chondrocyte-like cells were visualized on the most medial aspect of the anterior band at 20 weeks. Transmission electron microscopy revealed that these cells were structurally similar to chondrocytes (termed “morphological chondrocytes”) but with less abundant rough endoplasmic reticulum and low expression of <em>Acan</em> and <em>Col2a1</em> mRNA. Immunoreactivity for aggrecan and collagen type II was sparse in the extracellular matrix, but the areas of positivity were narrow. Immunoreactivity for hypoxia-inducible factor-1α was detected in the morphological chondrocytes and CD31-positive capillaries did not enter the disc, indicating an enhanced hypoxic environment in this region.</div></div><div><h3>Conclusions</h3><div>The presence of morphological chondrocytes in the articular disc region indicates an adaptation to the hypoxic environment rather than increased synthesis of cartilaginous matrix synthesis; hence, the rat TMJ disc can be regarded, in general, as a dense fibrous lamina rather than consisting of fibrocartilage.</div></div>","PeriodicalId":45851,"journal":{"name":"Journal of Oral Biosciences","volume":"67 4","pages":"Article 100694"},"PeriodicalIF":2.3000,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Oral Biosciences","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1349007925000830","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"DENTISTRY, ORAL SURGERY & MEDICINE","Score":null,"Total":0}
引用次数: 0

Abstract

Objectives

The structure of the temporomandibular joint (TMJ disc) articular disc as a dense fibrous lamina or fibrocartilage is an ongoing debate. To clarify this, we investigated TMJ disc cells in 3- to 20-week-old rats from the perspectives of general histology, ultrastructure, immunohistochemistry, and in situ hybridization.

Methods

Sections from paraffin-embedded TMJ discs were immunohistochemically stained using antibodies against aggrecan and collagen type II. Expression of Acan and Col2a1 mRNA was analyzed by in situ hybridization using antisense cRNA probes. Other samples were analyzed by transmission electron microscopy.

Results

Chondrocyte-like cells were visualized on the most medial aspect of the anterior band at 20 weeks. Transmission electron microscopy revealed that these cells were structurally similar to chondrocytes (termed “morphological chondrocytes”) but with less abundant rough endoplasmic reticulum and low expression of Acan and Col2a1 mRNA. Immunoreactivity for aggrecan and collagen type II was sparse in the extracellular matrix, but the areas of positivity were narrow. Immunoreactivity for hypoxia-inducible factor-1α was detected in the morphological chondrocytes and CD31-positive capillaries did not enter the disc, indicating an enhanced hypoxic environment in this region.

Conclusions

The presence of morphological chondrocytes in the articular disc region indicates an adaptation to the hypoxic environment rather than increased synthesis of cartilaginous matrix synthesis; hence, the rat TMJ disc can be regarded, in general, as a dense fibrous lamina rather than consisting of fibrocartilage.
大鼠颞下颌关节盘的结构特征:纤维软骨还是致密纤维层?
目的颞下颌关节盘的结构是致密纤维层还是纤维软骨一直是一个争论不休的问题。为了阐明这一点,我们从一般组织学、超微结构、免疫组织化学和原位杂交的角度研究了3 ~ 20周龄大鼠的TMJ椎间盘细胞。方法采用免疫组织化学方法对石蜡包埋的TMJ椎间盘切片进行抗聚集蛋白和II型胶原抗体染色。利用反义cRNA探针原位杂交分析Acan和Col2a1 mRNA的表达。其他样品用透射电镜分析。结果20周时,前腱束最内侧可见软骨细胞样细胞。透射电镜显示,这些细胞在结构上与软骨细胞相似(称为“形态软骨细胞”),但粗糙的内质网较少,Acan和Col2a1 mRNA的表达较低。细胞外基质中聚集蛋白和II型胶原蛋白的免疫反应性稀疏,阳性区域狭窄。形态学软骨细胞中检测到缺氧诱导因子-1α的免疫反应性,cd31阳性的毛细血管未进入椎间盘,表明该区域缺氧环境增强。结论关节盘区形态软骨细胞的出现表明其对缺氧环境的适应,而不是软骨基质合成的增加;因此,大鼠TMJ椎间盘一般可视为致密的纤维层,而不是由纤维软骨组成。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Journal of Oral Biosciences
Journal of Oral Biosciences DENTISTRY, ORAL SURGERY & MEDICINE-
CiteScore
4.40
自引率
12.50%
发文量
57
审稿时长
37 days
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:604180095
Book学术官方微信