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Ohshima H, Mishima K. Oral biosciences: The annual review 2022. J Oral Biosci 2023; 65:1-12. [PMID: 36740188 DOI: 10.1016/j.job.2023.01.008] [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: 01/14/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023]
Abstract
BACKGROUND The Journal of Oral Biosciences is devoted to advancing and disseminating fundamental knowledge concerning every aspect of oral biosciences. HIGHLIGHT This review features review articles in the fields of "Bone Cell Biology," "Tooth Development & Regeneration," "Tooth Bleaching," "Adipokines," "Milk Thistle," "Epithelial-Mesenchymal Transition," "Periodontitis," "Diagnosis," "Salivary Glands," "Tooth Root," "Exosome," "New Perspectives of Tooth Identification," "Dental Pulp," and "Saliva" in addition to the review articles by the winner of the "Lion Dental Research Award" ("Plastic changes in nociceptive pathways contributing to persistent orofacial pain") presented by the Japanese Association for Oral Biology. CONCLUSION The review articles in the Journal of Oral Biosciences have inspired its readers to broaden their knowledge about various aspects of oral biosciences. The current editorial review introduces these exciting review articles.
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Affiliation(s)
- Hayato Ohshima
- Division of Anatomy and Cell Biology of the Hard Tissue, Department of Tissue Regeneration and Reconstruction, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan.
| | - Kenji Mishima
- Division of Pathology, Department of Oral Diagnostic Sciences, Showa University School of Dentistry, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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Effect of Diet Consistency on Rat Mandibular Growth: A Geometric Morphometric and Linear Cephalometric Study. BIOLOGY 2022; 11:biology11060901. [PMID: 35741424 PMCID: PMC9220214 DOI: 10.3390/biology11060901] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary Craniofacial growth is affected by different environmental factors. One of these factors that seems to affect mandibulofacial growth is mastication. Diet consistency leads to different masticatory forces during mastication. Various researchers looked over the effect of diet consistency on craniofacial growth and more specifically on the mandible. The question of how diet consistency affects mandibular growth is still controversial since various studies had different results on that aspect. The results of this study support that there is a major effect of diet consistency on mandibular morphology. Thus, it contributes to a better understanding of evolution of mandibular growth. Abstract Background: Our study intended to investigate the null hypothesis that there is no effect of diet consistency on rat mandibular growth. Methods: A total sample of 24 female wistar rats, 30 days old, was used in this study. In the first group, the rats were fed soft diet and in the second group, they were fed hard diet for 60 days. On the 60th day, the rats were sedated and lateral cephalometric X-rays were taken. Lateral cephalometric X-rays were digitized with 7 craniofacial landmarks for the linear measurements, as well as with 12 curves and 90 landmarks, of which 74 were semilandmarks and 16 were fixed landmarks for morphometric analysis. These landmarks were exposed to Procrustes superimposition and Principal Component Analysis (PCA) to describe the shape variability of the mandible. Results: Means measurements of the soft diet group compared to those of the hard diet group were significantly different in linear and morphometric analysis measurements. The soft diet group of wistar rats revealed significant changes on the condyle (smaller), the angle of the mandible, and on the body of the mandible. Conclusions: Diet consistency affects the craniofacial growth of rats. Soft diet could be responsible for less mandibular growth.
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Responses of salivary glands to intake of soft diet. J Oral Biosci 2022; 64:210-216. [DOI: 10.1016/j.job.2022.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 03/24/2022] [Accepted: 03/29/2022] [Indexed: 11/20/2022]
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Yan F, Feng J, Yang L, Shi C. The effect induced by alternated mechanical loading on Notch-1 in mandibular condylar cartilage of growing rabbits. Bone Joint Res 2021; 10:437-444. [PMID: 34311570 PMCID: PMC8333037 DOI: 10.1302/2046-3758.107.bjr-2020-0234.r2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Aims The aim of our study is to investigate the effect induced by alternated mechanical loading on Notch-1 in mandibular condylar cartilage (MCC) of growing rabbits. Methods A total of 64 ten-day-old rabbits were randomly divided into two groups according to dietary hardness: normal diet group (pellet) and soft diet group (powder). In each group, the rabbits were further divided into four subgroups by feeding time: two weeks, four weeks, six weeks, and eight weeks. Animals would be injected 5-bromo-2′-deoxyuridine (BrdU) every day for one week before sacrificing. Histomorphometric analysis of MCC thickness was performed through haematoxylin and eosin (HE) staining. Immunochemical analysis was done to test BrdU and Notch-1. The quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were used to measure expression of Notch-1, Jagged-1, and Delta-like 1 (Dll-1). Results The thickness of MCC in the soft diet group was thinner than the one in normal diet group. Notch-1 was restricted in fibrous layer, proliferative layer, and hypertrophic layer. The expression of Notch-1 increased from two weeks to six weeks and then fell down. Notch-1 in normal diet group was higher than that in soft diet group in anterior part of MCC. The statistical differences of Notch-1 were shown at two, four, and six weeks (p < 0.05). The result of western blot and quantitative real-time PCR (qRT-PCR) showed the expression of Dll-1 and Jagged-1 rose from two to four weeks and started to decrease at four weeks. BrdU distributed in all layers of cartilage and subchondral bone. The number of BrdU-positive cells, which were less in soft diet group, was decreasing along with the experiment period. The significant difference was found at four, six, and eight weeks in anterior and posterior parts (p < 0.05). Conclusion The structure and proliferation of MCC in rabbits were sensitive to dietary loading changes. The proper mechanical loading was essential for transduction of Notch signalling pathway and development of mandibular condylar cartilage. Cite this article: Bone Joint Res 2021;10(7):437–444.
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Affiliation(s)
- Fan Yan
- School of Stomatology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jianying Feng
- School of Stomatology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Liu Yang
- School of Stomatology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Changjin Shi
- School of Stomatology, Zhejiang Chinese Medical University, Hangzhou, China
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Aung PT, Kato C, Abe Y, Ogawa T, Ishidori H, Fujita A, Okihara H, Kokai S, Ono T. Functional Analysis of Rhythmic Jaw Movements Evoked by Electrical Stimulation of the Cortical Masticatory Area During Low Occlusal Loading in Growing Rats. Front Physiol 2020; 11:34. [PMID: 32082192 PMCID: PMC7005729 DOI: 10.3389/fphys.2020.00034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/16/2020] [Indexed: 11/25/2022] Open
Abstract
The maturation of rhythmic jaw movements (RJMs) and related neuromuscular control has rarely been studied in animals, though this process is essential for regulating the development of stomatognathic functions. Previous studies have shown that occlusal hypofunction during growth alters masticatory performance. However, little is known about patterns of cortically-induced RJMs under conditions of soft-diet feeding during development. The aim of this study is to clarify the effect of low occlusal loading on the pattern of cortically induced RJMs and related neuromuscular responses in growing rats. Sixty-four 2-week-old male albino Wistar rats were randomly divided into two groups and fed on either a normal diet (control) or soft diet (experimental) soon after weaning. At 5, 7, 9, and 11 weeks of age, electromyographic (EMG) activity was recorded from the right masseter and anterior digastric muscles along with corresponding kinematic images in RJMs during repetitive intracortical microstimulation of the left cortical masticatory area (CMA). Rats in both groups showed an increase in gape size and lateral excursion until 9 weeks of age. The vertical jaw movement speed in both groups showed no significant difference between 5 and 7 weeks of age but increased with age from 9 to 11 weeks. Compared to the control group, the average gape size and vertical speed were significantly lower in the experimental group, and the pattern and rhythm of the jaw movement cycle were similar between both groups at each recording age. EMG recordings showed no age-related significant differences in onset latency, duration, and peak-to-peak amplitude. Moreover, we found significantly longer onset latency, smaller peak-to-peak amplitude, and greater drop-off mean and median frequencies in the experimental group than in the control group, while there was no significant difference in the duration between groups. These findings indicate that a lack of enough occlusal function in infancy impedes the development of patterns of RJMs and delays the neuromuscular response from specific stimulation of the CMA.
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Affiliation(s)
- Phyo Thura Aung
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Chiho Kato
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yasunori Abe
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takuya Ogawa
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hideyuki Ishidori
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Akiyo Fujita
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hidemasa Okihara
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Satoshi Kokai
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takashi Ono
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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Matsumoto K, Amemiya T, Ito M, Hayashi Y, Watanabe K, Dezawa K, Arai Y, Honda K. Newly developed mastication activity reduction procedure rapidly induces abnormal atrophic change of the mandibular condyle in young and elder experimental animal models. J Oral Sci 2020; 62:62-66. [PMID: 31996525 DOI: 10.2334/josnusd.18-0481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
This study was performed to develop a new rat model of reduced masticatory activity in order to assess the effect of this reduction on the morphology of the temporomandibular joint (TMJ) over time. Female rats were used, and ovariectomy was performed to simulate aged/postmenopausal status. Twenty-four SD rats aged 6 weeks were divided into four groups: ovariectomy/sham procedure (Ov/S); ovariectomy/reduced masticatory activity (Ov/RMA); non-Ov/S (NO/S); and non-Ov/RMA (NO/RMA). The RMA procedure involved grinding down the edges of the upper and mandibular incisors by about 3 mm and supplying the rats with a powdered diet. The bilateral TMJ was examined by micro-computed tomography at 0, 1, 2, 4, 6, and 8 weeks after the start of RMA. Condylar width was greater in the NO/S group than in the Ov/S group after the 2nd week, showing that ovariectomy reduced the width of the condyle. After the 2nd week, significant differences in condylar width were apparent between the NO/S and NO/RMA groups, and between the Ov/S and Ov/RMA groups. This RMA procedure appeared to provide a good model of reduced masticatory activity. The present findings in female rats suggest that reduction of appropriate mastication activity in the growth period results in poor growth of the mandibular condyle and immediately induces atrophy of the mandibular condyle under conditions simulating aged/postmenopausal status.
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Affiliation(s)
- Kunihito Matsumoto
- Department of Maxillofacial Radiology, Faculty of Dentistry, Kagoshima University.,Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
| | - Toshihiko Amemiya
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
| | - Motohiro Ito
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
| | - Yusuke Hayashi
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
| | - Kenichiro Watanabe
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
| | - Ko Dezawa
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
| | - Yoshinori Arai
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
| | - Kazuya Honda
- Department of Oral and Maxillofacial Radiology, Nihon University School of Dentistry
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Takahashi S, Takebuchi R, Taniwaki H, Domon T. Recovery of atrophic parotid glands in rats fed a liquid diet by switching to a pellet diet. Arch Oral Biol 2018; 96:39-45. [DOI: 10.1016/j.archoralbio.2018.08.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 08/22/2018] [Accepted: 08/24/2018] [Indexed: 11/29/2022]
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Abstract
PURPOSE OF REVIEW Investigate the developmental physiology of the temporomandibular joint (TMJ), a unique articulation between the cranium and the mandible. RECENT FINDINGS Principal regulatory factors for TMJ and disc development are Indian hedgehog (IHH) and bone morphogenetic protein (BMP-2). The mechanism is closely associated with ear morphogenesis. Secondary condylar cartilage emerges as a subperiosteal blastema on the medial surface of the posterior mandible. The condylar articular surface is immunoreactive for tenascin-C, so it is a modified fibrous periosteum with an underlying proliferative zone (cambrium layer) that differentiates into fibrocartilage. The latter cushions high loads and subsequently produces endochondral bone. The TMJ is a heavily loaded joint with three cushioning layers of fibrocartilage in the disc, as well as in subarticular zones in the fossa and mandibular condyle. The periosteal articular surface produces fibrocartilage to resist heavy loads, and has unique healing and adaptive properties for maintaining life support functions under adverse environmental conditions.
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Affiliation(s)
- David L Stocum
- School of Science, Department of Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, IN, USA
| | - W Eugene Roberts
- School of Dentistry, Department of Orthodontics & Orofacial Genetics, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, IN, USA.
- Department of Orthodontics, Loma Linda University, Loma Linda, CA, USA.
- Advanced Dental Education, St. Louis University, St. Louis, MO, USA.
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Denes BJ, Lazzarotto B, Bresin A, Kiliaridis S. Effect of different masticatory functional demands on the 3D mandibular condyle morphology of growing rats using posterior bite-blocks. Eur J Orthod 2018; 40:312-316. [PMID: 29040460 DOI: 10.1093/ejo/cjx072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Background and objectives Apart from the primary effect of bite-blocks on tooth position, they may also influence the mandibular condylar growth. Our aim was to investigate their influence on the condylar morphology, with variable masticatory forces. Material and methods Fifty-two 4-week old male rats were divided into hard and soft diet groups in order to create individuals with different masticatory muscle capacity. Two weeks later, they were equally divided into bite-block and control groups. After a total of 6 weeks experimental time, the animals were sacrificed. The mandibles were scanned with high-resolution micro-CT and 3D analysis was performed on the condylar neck and head of the condyle. The volume and the length of the condylar process were measured. Statistical analysis was done with a one-way analysis of variance. Results The use of bite-blocks decreased the length of the condylar process (P = 0.001) as well as the volume of the condylar neck (P = 0.001) and head (P = 0.006). The soft diet decreased the volume of the condylar neck (P < 0.001) and head (P < 0.001) two to three times more than the bite-blocks but did not affect the condylar process length. The interaction between the two variables was not statistically significant. Conclusions Both the bite-block appliance and weak masticatory muscle function reduced the volume at all regions of the condylar process, although the functional factor had a substantially greater effect. However, only the bite-block appliance affected the condylar process length. In the presence of both factors, an additive effect was found but no interaction detected.
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Affiliation(s)
- Balazs J Denes
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medecine, University de Geneva, Switzerland
| | - Benjamin Lazzarotto
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medecine, University de Geneva, Switzerland
| | - Andrea Bresin
- Specialist clinic of Orthodontics, University Clinics, Public dental service Region Västra Götaland, Göteborg, Sweden
| | - Stavros Kiliaridis
- Department of Orthodontics, Clinique Universitaire de Médecine Dentaire, Faculty of Medecine, University de Geneva, Switzerland
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Dobsak T, Heimel P, Tangl S, Schwarze UY, Schett G, Gruber R. Impaired periodontium and temporomandibular joints in tumour necrosis factor-α transgenic mice. J Clin Periodontol 2017; 44:1226-1235. [DOI: 10.1111/jcpe.12799] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2017] [Indexed: 12/24/2022]
Affiliation(s)
- Toni Dobsak
- Core Facility Hard Tissue and Biomaterial Research; Karl Donath Laboratory; School of Dentistry; Medical University of Vienna; Vienna Austria
- Austrian Cluster for Tissue Regeneration; Vienna Austria
| | - Patrick Heimel
- Core Facility Hard Tissue and Biomaterial Research; Karl Donath Laboratory; School of Dentistry; Medical University of Vienna; Vienna Austria
- Austrian Cluster for Tissue Regeneration; Vienna Austria
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology; Vienna Austria
| | - Stefan Tangl
- Core Facility Hard Tissue and Biomaterial Research; Karl Donath Laboratory; School of Dentistry; Medical University of Vienna; Vienna Austria
- Austrian Cluster for Tissue Regeneration; Vienna Austria
| | - Uwe Y. Schwarze
- Austrian Cluster for Tissue Regeneration; Vienna Austria
- Department of Oral Biology; School of Dentistry; Medical University of Vienna; Vienna Austria
| | - Georg Schett
- Department of Internal Medicine 3; Friedrich Alexander University of Erlangen- Nuremberg; Erlangen Germany
| | - Reinhard Gruber
- Austrian Cluster for Tissue Regeneration; Vienna Austria
- Department of Oral Biology; School of Dentistry; Medical University of Vienna; Vienna Austria
- Department of Periodontology; School of Dental Medicine; University of Bern; Bern Switzerland
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Fan Y, Jianying F, Chenyan L, Pan W, Zhe S, Changjing S. [Influence on Indian hedgehog-parathyroid hormone-like related protein pathway induced by altered masticatory loading in the condylar cartilage of growing rabbits]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2017; 35:127-132. [PMID: 28682540 DOI: 10.7518/hxkq.2017.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To determine the influence of altered masticatory loading on Indian hedgehog (Ihh)-parathyroid hormone-like related protein (PThrP) pathway in the condylar cartilage of growing rabbits. METHODS A total of 48 10-day-old rabbits were randomly divided into two groups and fed different kinds of food, such as solid diet and soft diet. The animals were sacrificed after 2, 4, 6, and 8 weeks. Difference of Ihh and PThrP expression levels induced by altered masticatory loading was tested by hematoxylin-eosin (HE), immunohistochemistry, Western blot, and real-time polymerase chain reaction (PCR). RESULTS The thickness of condylar cartilage and expression levels of Ihh and PThrP proteins and mRNA of the solid diet groups exceeded those of the soft diet groups. The decreasing tendencies of the expression levels of Ihh and PThrP proteins and mRNA were observed at 2, 4, 6, 8 weeks. CONCLUSIONS Low masticatory loading may delay or inhibit the development of condylar cartilage and its growing factors Ihh and PThrP. Therefore, masticatory loading plays an important role in the development of condylar cartilage.
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Affiliation(s)
- Yan Fan
- College of Stomatology, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Feng Jianying
- College of Stomatology, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Liu Chenyan
- College of Stomatology, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Wang Pan
- College of Stomatology, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Sun Zhe
- College of Stomatology, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Shi Changjing
- College of Stomatology, Zhejiang Chinese Medical University, Hangzhou 310053, China
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Takahashi S, Uekita H, Taniwaki H, Domon T. Acinar cell response to liquid diet during rats' growth period differs in submandibular and sublingual glands from that in parotid glands. Tissue Cell 2017; 49:275-284. [PMID: 28222888 DOI: 10.1016/j.tice.2017.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 01/25/2017] [Accepted: 01/27/2017] [Indexed: 11/29/2022]
Abstract
Continuously feeding a liquid diet to growing rodents strongly inhibits parotid gland growth, due to suppressed growth of acinar cells. This study investigated whether a liquid diet had a similar effect on submandibular and sublingual glands of growing rats. Rats were weaned on day 21 after birth and then fed a pellet diet in the control group and a liquid diet in the experimental group for 0, 1, 2, 4, and 8 weeks. Their submandibular and sublingual glands were excised, weighed, and examined histologically, immunohistochemically (using antibodies to 5'-bromo-2-deoxyuridine and cleaved caspase 3), and ultrastructurally. The submandibular glands did not significantly differ between the control and experimental groups at all tested points. Only at Week 8, acinar cell area and 5'-bromo-2-deoxyuridine-labeling index of acinar cells in sublingual glands were significantly lower in the experimental group than in the control group. These results show that a liquid diet during rats' growth period had no effect on acinar cells in their submandibular glands, and only a slight effect on acinar cells in their sublingual glands of growing rats, in contrast to the marked effect of a liquid diet on parotid glands.
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Affiliation(s)
- Shigeru Takahashi
- Department of Oral Functional Anatomy, Hokkaido University Graduate School of Dental Medicine, Sapporo, 060-8586, Japan.
| | - Hiroki Uekita
- Department of Crown and Bridge Prosthodontics, Hokkaido University Graduate School of Dental Medicine, Sapporo, 060-8586, Japan
| | - Hiroto Taniwaki
- Department of Oral Functional Anatomy, Hokkaido University Graduate School of Dental Medicine, Sapporo, 060-8586, Japan
| | - Takanori Domon
- Department of Oral Functional Anatomy, Hokkaido University Graduate School of Dental Medicine, Sapporo, 060-8586, Japan
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Uekita H, Takahashi S, Domon T, Yamaguchi T. Changes in collagens and chondrocytes in the temporomandibular joint cartilage in growing rats fed a liquid diet. Ann Anat 2015; 202:78-87. [PMID: 26434755 DOI: 10.1016/j.aanat.2015.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/27/2015] [Accepted: 08/20/2015] [Indexed: 10/23/2022]
Abstract
The temporomandibular joint (TMJ) of growing rats fed a soft diet is reported to be smaller in size and to have thinner condyle and glenoid fossa cartilage than rats fed a solid diet. The aim of this study was to determine the effect of a soft diet on the collagens and chondrocytes in the growing TMJ cartilage. Forty-eight male Wistar rats were divided into a control group fed a solid diet and an experimental group fed a liquid diet for 1-8 weeks. After the experimental period, the TMJs were harvested and examined histologically, immunohistochemically for collagen types I, II, and X, and with transmission electron microscopy. The condylar cartilage in the experimental rats showed weak immunoreactions for three types of collagens compared with the controls. The ultrastructure had fewer fine collagen fibrils in the experimental rats compared with that of the controls. The glenoid fossa cartilage in the experimental rats showed narrower Alcian blue-positive areas than the control staining. The immunoreactions for three types of collagen in the experimental rats were also weaker than those of the controls. The chondrocytes in the experimental rats appeared dark, had extended thin cytoplasmic processes, and had formed gap junctions, as assessed by transmission electron microscopy. Fewer fine collagen fibrils, but thick bands of collagen fibrils were observed in the glenoid fossa of the experimental cartilage. The results of the present study showed that a liquid diet had deleterious effects on the quality and quantity of collagens and chondrocytes in the TMJ cartilage in growing rats.
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Affiliation(s)
- Hiroki Uekita
- Division of Crown and Bridge Prosthodontics, Department of Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan; Division of Oral Functional Anatomy, Department of Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan.
| | - Shigeru Takahashi
- Division of Oral Functional Anatomy, Department of Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Takanori Domon
- Division of Oral Functional Anatomy, Department of Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
| | - Taihiko Yamaguchi
- Division of Crown and Bridge Prosthodontics, Department of Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan
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Takahashi S, Uekita H, Kato T, Inoue K, Domon T. Growth of rat parotid glands is inhibited by liquid diet feeding. Tissue Cell 2015; 47:336-41. [PMID: 25956847 DOI: 10.1016/j.tice.2015.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/26/2015] [Accepted: 04/09/2015] [Indexed: 11/26/2022]
Abstract
This study investigated how liquid diet feeding affects the growth of parotid glands. We weaned 21-day-old rats and thereafter fed them a pellet diet (control group) or a liquid diet (experimental group) for 0, 1, 2, 4, or 8 weeks. Their parotid glands were excised, weighed, examined, and tested for 5-bromo-2'-deoxyuridine (BrdU) and cleaved caspase-3 (Casp-3) as markers of proliferation and apoptosis, respectively. Parotid gland weights were consistently smaller in experimental animals than in controls. Morphometrical analysis showed that control group acinar cells increased in area during the experiment, but experimental group acinar cells were almost unchanged. Labeling indices of BrdU in acinar cells in both groups declined during the experiment, but were consistently lower in the experimental group than in controls. Casp-3-positive acinar cells were rare in both groups, which consistently express significantly similar Casp-3 levels. Ultrastructurally, terminal portions of the experimental parotid glands consisted of a few acinar cells that were smaller than those in controls. Control acinar cells showed mitotic figures within short experimental periods, but not in experimental glands. These observations indicate that liquid diet feeding inhibits growth of parotid glands in growing rats through suppression of growth and proliferation of individual acinar cells, but not through apoptosis.
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Affiliation(s)
- Shigeru Takahashi
- Department of Oral Functional Anatomy, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan.
| | - Hiroki Uekita
- Department of Oral Functional Anatomy, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan
| | - Tsuyoshi Kato
- Department of Oral Functional Anatomy, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan
| | - Kiichiro Inoue
- Department of Oral Functional Anatomy, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan
| | - Takanori Domon
- Department of Oral Functional Anatomy, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan
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