title: Changes in collagens and chondrocytes in the temporomandibular joint cartilage in growing rats fed a liquid diet.
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.
authors.affiliation: 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. Electronic address: hiroki-uekita@den.hokudai.ac.jp.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Uekita
authors.affiliation: Division of Oral Functional Anatomy, Department of Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Division of Oral Functional Anatomy, Department of Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Domon
authors.affiliation: Division of Crown and Bridge Prosthodontics, Department of Oral Functional Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan.
authors.forename: Taihiko
authors.initials: T
authors.lastname: Yamaguchi
mesh_terms: D000423:Alcian Blue; D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D002452:Cell Count; D019902:Chondrocytes; D003094:Collagen / Q000378:metabolism*; D004032:Diet; D017629:Gap Junctions / Q000648:ultrastructure; D007150:Immunohistochemistry; D008297:Male; D008335:Mandibular Condyle / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013704:Temporomandibular Joint / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D003094:Collagen; D000423:Alcian Blue
keywords: Cartilage; Chondrocyte; Collagen; Liquid diet; Temporomandibular joint