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Ghasemzadeh F, Mortazavi N, Mallahi M, Gharib MH, Behnampour N, Badeleh MT, Asgari N. Association between psychological stress and mandibular condyle structure: an analytical cross-sectional study. BMC Musculoskelet Disord 2024; 25:563. [PMID: 39030530 PMCID: PMC11264819 DOI: 10.1186/s12891-024-07692-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Accepted: 07/15/2024] [Indexed: 07/21/2024] Open
Abstract
OBJECTIVE The potential influence of psychological factors on temporomandibular joint disorders has been clinically documented. To date, all research examining the impact of psychological stress on the temporomandibular joint has been conducted on animals. This study aims to explore the relationship between psychological stress and the structure of the human mandibular condyle. METHODS This cross-sectional study was performed on individuals, who were referred to the radiology division of 5th Azar Hospital for head and neck Computed Tomography (CT) scans. All participants completed a perceived stress questionnaire to determine their level of stress. Bone density and cortical bone thickness were measured as indicators of mandibular condyle structure. Based on multi-slice CT scan data, bone density was calculated in the anterior, middle, and posterior mandibular condyle. The cortical bone thickness was also measured at the anterior and posterior mandibular condyle. Statistical analysis was performed in R 4.0.2 software. RESULTS Seventy individuals, aged 18-59 years, participated in this study. The CT scans revealed a decrease in Hounsfield units (HU) and bone mineral density (BMD) in both the anterior and posterior regions. However, in the high-stress group, there was no significant difference in cortical bone thickness in the anterior and posterior regions of the condyle, nor in HU and BMD in the middle region of the condyle. An inverse correlation was observed between BMD and perceived stress in the anterior, middle, and posterior regions of both condyles. CONCLUSION The current findings indicate that recent psychological stress is associated with changes in the structure of the condyle.
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Affiliation(s)
- Fatemeh Ghasemzadeh
- Dental Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Nazanin Mortazavi
- Dental Research Center, Golestan University of Medical Sciences, Gorgan, Iran.
| | - Mysa Mallahi
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Golestan University of Medical Sciences, Gorgan, Iran
| | - Mohammad Hadi Gharib
- Department of Radiology, School of Medicine, 5th Azar Hospital, Golestan University of Medical Sciences, Gorgan, Iran
| | - Naser Behnampour
- Health Management and Social Development Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Mohammad Taghi Badeleh
- Department of Psychology, School of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
| | - Negar Asgari
- Department of Microbiology, School of Medicine, Golestan University of Medical Sciences, Gorgan, Iran
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Chen X, Cheng Z, Xu J, Wang Q, Zhao Z, Jiang Q. Causal effects of educational attainment on temporomandibular disorders and the mediating pathways: A Mendelian randomization study. J Oral Rehabil 2024; 51:817-826. [PMID: 38205584 DOI: 10.1111/joor.13654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/19/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024]
Abstract
BACKGROUND As one of the most important indicators of socioeconomic status, educational attainment (EA) exhibits a strong association with temporomandibular disorders (TMDs). Despite this link, there is a lack of evidence regarding the causal role of EA in either facilitating or preventing TMDs. OBJECTIVE This study aimed to investigate the causal effect of education on TMDs and explore potential mediating pathways. METHODS Utilizing summary statistics from genome-wide association studies on years of schooling (N = 766 345) and TMDs (N = 211 023), we conducted Mendelian randomization (MR) to assess the overall effect of education. Additionally, a two-step MR approach was employed to evaluate 30 potential mediators and calculate the mediation proportions in the association. Comprehensive sensitivity analyses were used to verify the robustness, heterogeneity, and pleiotropy. RESULTS Univariable MR analyses revealed a causal effect of lower EA on an increased risk of TMDs (OR: 0.53, 95% CI: 0.43-0.66, p < .001). Five out of 30 modifiable factors were identified as causal mediators in the associations of EA with TMDs, including feeling nervous (mediation proportion: 11.6%), feeling tense (10.2%), depression (9.6%), feeling worry (7.6%) and daily smoking (8.9%). Meanwhile, no pleiotropy was detected in the analyses (p > .05). CONCLUSION Our findings supported that higher EA has a protective effect on the onset of TMDs, with partial mediation by psychological disorders and daily smoking. Interventions on these factors thus have the potential of substantially reducing the burden of TMDs attributed to low education.
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Affiliation(s)
- Xin Chen
- Department of Oral and Maxillofacial Surgery, Jiangyin People's Hospital Affiliated to Nantong University, Jiangyin, China
| | - Zheng Cheng
- Department of Oral and Maxillofacial Surgery, Jiangyin People's Hospital Affiliated to Nantong University, Jiangyin, China
| | - Junyu Xu
- Department of Oral and Maxillofacial Surgery, Jiangyin People's Hospital Affiliated to Nantong University, Jiangyin, China
| | - Qianyi Wang
- Department of Cardiology, Jiangyin People's Hospital Affiliated to Nantong University, Jiangyin, China
| | - Zhibai Zhao
- Department of Oral Mucosal Diseases, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Qianglin Jiang
- Department of Oral and Maxillofacial Surgery, Jiangyin People's Hospital Affiliated to Nantong University, Jiangyin, China
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Marin R, Rolim GS, De Moraes ABA, Graner KM. DISFUNÇÕES TEMPOROMANDIBULARES E FATORES PSICOLÓGICOS: UMA REVISÃO DE LITERATURA. PSICOLOGIA EM ESTUDO 2022. [DOI: 10.4025/psicolestud.v27i0.47363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
As disfunções temporomandibulares (DTM) são condições biológicas que envolvem sinais e sintomas como dores crônicas na articulação temporomandibular e nos músculos da mastigação. O presente estudo tem como objetivo identificar quais e como conceitos psicológicos são descritos em artigos de intervenções odontológicas relacionadas à DTM, em artigos de revisão sistemática. Para isto foram utilizadas três bases de dados na busca e seleção: PubMed, Scopus e Web of Science. Aplicou-se em todas estas bases de dados a mesma formulação de termos-chave. Foram selecionados os artigos de revisões, publicados entre 2000 e 2017, escritos em inglês. Dos 4.092 artigos encontrados, sete foram selecionados descrevendo intervenções psicológicas envolvidas com o tratamento da DTM. Todos os artigos selecionados foram analisados com base em seus objetivos e discussões, considerando as características de apresentação e compreensão das variáveis psicológicas relacionadas à disfunção temporomandibular e às intervenções utilizadas. Para tanto, foram realizadas análises qualitativas e quantitativas. Pode-se concluir que a compreensão e a definição das variáveis psicológicas relacionadas à DTM não são evidentes, o que dificulta a produção de resultados claros sobre a eficácia dos diagnósticos e intervenções para DTM.
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Xiang T, Tao ZY, Liao LF, Wang S, Cao DY. Animal Models of Temporomandibular Disorder. J Pain Res 2021; 14:1415-1430. [PMID: 34079358 PMCID: PMC8166243 DOI: 10.2147/jpr.s303536] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 04/04/2021] [Indexed: 12/12/2022] Open
Abstract
Temporomandibular disorders (TMD) are a group of diseases in the oral and maxillofacial region that can manifest as acute or chronic persistent pain, affecting millions of people worldwide. Although hundreds of studies have explored mechanisms and treatments underlying TMD, multiple pathogenic factors and diverse clinical manifestations make it still poorly managed. Appropriate animal models are helpful to study the pathogenesis of TMD and explore effective treatment measures. At present, due to the high cost of obtaining large animals, rodents and rabbits are often used to prepare TMD animal models. Over the past decade, various animal models have been intensively developed to understand neurobiological and molecular mechanisms of TMD, and seek effective treatments. Although these models cannot carry out all clinical features, they are valuable in revealing the mechanisms of TMD and creating curative access. Currently, there are multitudinous animal models of TMD research. They can be constructed in different means and summarized into four ways according to the various causes and symptoms, including chemical induction (intra-articular injection of ovalbumin, collagenase, formalin, vascular endothelial growth factor, intramuscular injection of complete Freund’s adjuvant, etc.), mechanical stress stimulation (passive mouth opening, change of chewing load), surgical operation (partial disc resection, joint disc perforation) and psychological stress induction. Here, we summarize and discuss different approaches of animal models for determining neurophysiological and mechanical mechanisms of TMD and assess their advantages and limitations, respectively.
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Affiliation(s)
- Ting Xiang
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Research Center of Stomatology, Xi'an Jiaotong University College of Stomatology, Xi'an, Shaanxi, 710004, People's Republic of China.,Department of Orthodontics, Xi'an Jiaotong University College of Stomatology, Xi'an, Shaanxi, 710004, People's Republic of China
| | - Zhuo-Ying Tao
- Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, Sai Ying Pun, Hong Kong, 999077, People's Republic of China
| | - Li-Fan Liao
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Research Center of Stomatology, Xi'an Jiaotong University College of Stomatology, Xi'an, Shaanxi, 710004, People's Republic of China
| | - Shuang Wang
- Department of Orthodontics, Xi'an Jiaotong University College of Stomatology, Xi'an, Shaanxi, 710004, People's Republic of China
| | - Dong-Yuan Cao
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Research Center of Stomatology, Xi'an Jiaotong University College of Stomatology, Xi'an, Shaanxi, 710004, People's Republic of China
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Lyros I, Makrygiannakis MA, Lykogeorgos T, Ferdianakis E, Tsolakis AI. Posterior Mandibular Displacement-A Systematic Review Based on Animal Studies. Animals (Basel) 2021; 11:ani11030823. [PMID: 33804016 PMCID: PMC8000001 DOI: 10.3390/ani11030823] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/04/2021] [Accepted: 03/12/2021] [Indexed: 12/31/2022] Open
Abstract
Treating extreme mandibular growth is challenging. The mandible is pushed backwards to address itsprotrusion. Nevertheless, conclusions after such displacement in animals have been contradictory. The aim of the present review is to present measurable alterations of the mandible and the condyle following retractionin healthy rats or rabbits. PubMed, Scopus and Web of Science were accessed for relevant studies up to October 2020. Eligibility was determined by the PICOS process, while the risk of bias was estimated with SYRCLE's risk of bias tool. Retraction resulted in a more distal molar occlusion and the condyle rested more posteriorly. Mandibular anteroposterior bilateral growth restriction was achieved, the condylar process measured smaller and its angulation increased. The condylar neck thickened, its posterior surface flattened, the coronoid process was measured longer, and enlarged retromolar density was registered. Differences in the ramus height and the intercondylar distance were insignificant. Changes persisted for the period of study and subsequently the mandible resumed its inherited growth pattern. The timing of mandibular shaping and TMJ outcomes might depend on the properties of the applied force. Stability is of concern and well-structured, long-term studies are expected to resolve the issue and further clarify the results of posterior mandibular displacement.
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Affiliation(s)
- Ioannis Lyros
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (M.A.M.); (E.F.); (A.I.T.)
- Correspondence:
| | - Miltiadis A. Makrygiannakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (M.A.M.); (E.F.); (A.I.T.)
| | - Theodoros Lykogeorgos
- Paediatric Dentist, “Hatzikosta” General Hospital of Messolonghi, 30200 Messolonghi, Greece;
| | - Efstratios Ferdianakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (M.A.M.); (E.F.); (A.I.T.)
| | - Apostolos I. Tsolakis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, 11527 Athens, Greece; (M.A.M.); (E.F.); (A.I.T.)
- Department of Orthodontics, Case Western Reserve University, Cleveland, OH 44106, USA
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Venkatesh SB, Shetty SS, Kamath V. Prevalence of Temporomandibular Disorders and its Correlation with Stress and Salivary Cortisol Levels among Students. PESQUISA BRASILEIRA EM ODONTOPEDIATRIA E CLÍNICA INTEGRADA 2021. [DOI: 10.1590/pboci.2021.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Waked JP, Canuto MPLDAM, Gueiros MCSN, Aroucha JMCNL, Farias CG, Caldas ADF. Model for Predicting Temporomandibular Dysfunction: Use of Classification Tree Analysis. Braz Dent J 2020; 31:360-367. [PMID: 32901710 DOI: 10.1590/0103-6440202003279] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/17/2020] [Indexed: 11/21/2022] Open
Abstract
The aim of this study was to construct a predictive model that uses classification tree statistical analysis to predict the occurrence of temporomandibular disorder, by dividing the sample into groups of high and low risk for the development of the disease. The use of predictive statistical approaches that facilitate the process of recognizing and/or predicting the occurrence of temporomandibular disorder is of interest to the scientific community, for the purpose of providing patients with more adequate solutions in each case. This was a cross-sectional analytical population-based study that involved a sample of 776 individuals who had sought medical or dental attendance at the Family Health Units in Recife, PE, Brazil. The sample was submitted to anamnesis using the instrument Research Diagnostic Criteria for Temporomandibular Disorders. The data were inserted into the software Statistical Package for the Social Sciences 20.0 and analyzed by the Pearson Chi-square test for bivariate analysis, and by the classification tree method for the multivariate analysis. Temporomandibular disorder could be predicted by orofacial pain, age and depression. The high-risk group was composed of individuals with orofacial pain, those between the ages of 25 and 59 years and those who presented depression. The low risk group was composed of individuals without orofacial pain. The authors were able to conclude that the best predictor for temporomandibular disorder was orofacial pain, and that the predictive model proposed by the classification tree could be applied as a tool for simplifying decision making relative to the occurrence of temporomandibular disorder.
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Affiliation(s)
- Jorge P Waked
- Center for Rural Health and Technology, Academic Unit of Biological Sciences, UFCG - Universidade Federal de Campina Grande, Patos, PB, Brazil
| | - Mariana P L de A M Canuto
- Health Science Center, Department of Clinical and Preventive Dentistry, UFPE - Universidade Federal de Pernambuco, Recife, PE, Brazil
| | - Maria Cecilia S N Gueiros
- Health Science Center, Department of Clinical and Preventive Dentistry, UFPE - Universidade Federal de Pernambuco, Recife, PE, Brazil
| | - João Marcílio C N L Aroucha
- Health Science Center, Department of Clinical and Preventive Dentistry, UFPE - Universidade Federal de Pernambuco, Recife, PE, Brazil
| | - Cleysiane G Farias
- Health Science Center, Department of Clinical and Preventive Dentistry, UFPE - Universidade Federal de Pernambuco, Recife, PE, Brazil
| | - Arnaldo de F Caldas
- Health Science Center, Department of Clinical and Preventive Dentistry, UFPE - Universidade Federal de Pernambuco, Recife, PE, Brazil
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Effects of Twin Inclined Plane Device on Adaptation and Ultrastructure Variations in Condyle of Growing Rats. BIOMED RESEARCH INTERNATIONAL 2019; 2019:3069347. [PMID: 31815128 PMCID: PMC6877931 DOI: 10.1155/2019/3069347] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/21/2019] [Accepted: 10/23/2019] [Indexed: 11/17/2022]
Abstract
Objective This study investigates the effects of using a twin inclined plane device (TIPD) on the remolding and ultrastructure variation of mandibular condyle in growing rats. Materials and Methods Forty-eight male Wistar rats (six weeks old, body weight of approximately 190–210 g) were divided into experimental group (wearing appliance, n = 32) and control group (no appliance, n = 16). Samples were collected on days 3, 14, 30, and 60. The immunohistochemical analysis for vascular endothelial growth factor (VEGF) and type II collagen was carried out. Tartrate-resistant acid phosphatase (TRAP) reaction was performed to evaluate the osteoclastic activity. Three-dimensional morphometric images were reconstructed for morphometric analysis by microcomputed tomography (micro-CT). The ultrastructure of the condylar surface was observed by scanning electron microscopy (SEM). Results The expression of VEGF significantly increased, while the expression of type II collagen decreased in the experimental group at days 30 and 60. Furthermore, the enhanced osteoclast activity was observed under the subchondral bone, which was highest at day 30, and decreased to the lowest at day 60 in the experimental group. In addition, adaptive subchondral bone remolding in the posterior part of the condyle was observed at day 60 in the experimental group, and the SEM revealed the ultrastructure variations after installation of the TIPD. However, these changes began to reverse after 30 days. Conclusion Condylar tissue changes point to the osteoclastic activity in the posterior region of the condyle. These adaptive changes point to bone resorption in the posterior condyle. Type II collagen and VEGF contribute to the MCC remolding induced by the TIPD. The ultrastructural changes in the posterior condylar area in response to mechanical stresses are recoverable at the initial stage.
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VEGF promotes cartilage angiogenesis by phospho-ERK1/2 activation of Dll4 signaling in temporomandibular joint osteoarthritis caused by chronic sleep disturbance in Wistar rats. Oncotarget 2017; 8:17849-17861. [PMID: 28147322 PMCID: PMC5392291 DOI: 10.18632/oncotarget.14874] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/18/2017] [Indexed: 11/25/2022] Open
Abstract
Chronic sleep disturbance (CSD) has been linked to the development of temporomandibular joint osteoarthritis (TMJ-OA). While the pathogenesis of TMJ-OA is unclear, recent studies indicate that osteochondral angiogenesis is important. We developed a rat model of CSD induced TMJ-OA to investigate the changes caused by sleep disturbance and to correlate them with vascular invasion in the TMJ. We found pathological alterations and an increased microvessel density in the rat TMJ following CSD. VEGF, Dll4 and p-ERK1/2, the expression of angiogenic factors, were highly expressed in the rat mandibular condylar cartilage and their expression increased with CSD. Furthermore, we show that VEGF-induce activation of ERK1/2, which in turn, increases Dll4 expression. Together, our results suggest that CSD can cause OA-like pathological alterations in the rat TMJ by increasing angiogenesis.
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Ma C, Wu G, Wang Z, Wang P, Wu L, Zhu G, Zhao H. Effects of chronic sleep deprivation on the extracellular signal-regulated kinase pathway in the temporomandibular joint of rats. PLoS One 2014; 9:e107544. [PMID: 25226519 PMCID: PMC4167193 DOI: 10.1371/journal.pone.0107544] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 08/11/2014] [Indexed: 12/17/2022] Open
Abstract
Objectives To examine the possible involvement and regulatory mechanisms of extracellular signal-regulated kinase (ERK) pathway in the temporomandibular joint (TMJ) of rats subjected to chronic sleep deprivation (CSD). Methods Rats were subjected to CSD using the modified multiple platform method (MMPM). The serum levels of corticosterone (CORT) and adrenocorticotropic hormone (ACTH) were tested and histomorphology and ultrastructure of the TMJ were observed. The ERK and phospho-ERK (p-ERK) expression levels were detected by Western blot analysis, and the MMP-1, MMP-3, and MMP-13 expression levels were detected by real-time quantitative polymerase chain reaction (PCR) and Western blotting. Results The elevated serum CORT and ACTH levels confirmed that the rats were under CSD stress. Hematoxylin and eosin (HE) staining and scanning electron microscopy (SEM) showed pathological alterations in the TMJ following CSD; furthermore, the p-ERK was activated and the mRNA and protein expression levels of MMP-1, MMP-3, and MMP-13 were upregulated after CSD. In the rats administered with the selective ERK inhibitor U0126, decreased tissue destruction was observed. Phospho-ERK activation was visibly blocked and the MMP-1, MMP-3, and MMP-13 mRNA and protein levels were lower than the corresponding levels in the CSD without U0126 group. Conclusion These findings indicate that CSD activates the ERK pathway and upregulates the MMP-1, MMP-3, and MMP-13 mRNA and protein levels in the TMJ of rats. Thus, CSD induces ERK pathway activation and causes pathological alterations in the TMJ. ERK may be associated with TMJ destruction by promoting the expression of MMPs.
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Affiliation(s)
- Chuan Ma
- Department of Stomatology, Jinan Military General Hospital, Jinan City, Shandong Province, China
- College of Stomatology, Shandong University, Jinan City, Shandong Province, China
- Shandong Provincial Key Laboratory of Oral Biomedicine, Jinan City, Shandong Province, China
| | - Gaoyi Wu
- Department of Stomatology, Jinan Military General Hospital, Jinan City, Shandong Province, China
| | - Zhaoling Wang
- Department of Stomatology, Jinan Military General Hospital, Jinan City, Shandong Province, China
| | - Peihuan Wang
- Department of Stomatology, Jinan Military General Hospital, Jinan City, Shandong Province, China
| | - Longmei Wu
- cardiovascular medicine, He Bei medical University, Shijiazhuang City, Hebei Province, China
| | - Guoxiong Zhu
- Department of Stomatology, Jinan Military General Hospital, Jinan City, Shandong Province, China
| | - Huaqiang Zhao
- College of Stomatology, Shandong University, Jinan City, Shandong Province, China
- Shandong Provincial Key Laboratory of Oral Biomedicine, Jinan City, Shandong Province, China
- * E-mail:
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Psychological stress alters microstructure of the mandibular condyle in rats. Physiol Behav 2013; 110-111:129-39. [PMID: 23313405 DOI: 10.1016/j.physbeh.2013.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 01/02/2013] [Accepted: 01/06/2013] [Indexed: 11/21/2022]
Abstract
Psychological stress plays an important role in the occurrence and development of temporomandibular joint disorder (TMD). The correlation between psychological factors and TMD has been clinically shown, but the influence of psychological stress on the temporomandibular joint (TMJ) structure still lacks direct evidence. Here, we used communication box to establish the rat model of psychological stress. The stress level of animals was estimated by the elevated plus maze (EPM) test and hormonal assays. The histomorphology and three-dimensional microstructure of the rat condyles were observed by hematoxylin-eosin (HE) staining and Micro-CT, respectively. Compared with control rats, the anxious state of the stressed rats was evidenced by higher plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT), as well as lower ratios of open arm entries and time and lower time spent in open arms after 1, 2, 3, 4 and 5 week(s) post-exposure to psychological stimuli. HE staining and histomorphometric data analysis showed decreased thicknesses of the central and posterior condylar cartilages in stressed rats at weeks 3, 4 and 5, with the most obvious changes in the posterior part characterized by debonding and thinned fibrous layer, thickened proliferative layer, thinned mature layer and hypertrophic layer. Moreover, Micro-CT scanning revealed local lesion of the subchondral bone in the posterior condylar cartilages of stressed rats at week 5. Our findings indicate that pathologic changes of the histomorphology and three-dimensional microstructure occur in the condyles of stressed rats, hinting us a potential link between psychological factors and the pathogenesis or progression of TMD.
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