Biomaterial Database

A stereologic analysis of collagen phagocytosis by periodontal ligament fibroblasts during occlusal hypofunction in the rat. 1982

D A Deporter, and E L Svoboda, and W Motruk, and T P Howley

Maxillary molars were extracted unilaterally from 4 young male rats so as to leave the agonist mandibular molars in hypofunction. The mandibular molars on the opposite side of the mouth acted as controls. Three days later, the animals were killed by perfusion and all mandibular molars removed en bloc. After demineralization, each block was trimmed, prepared for electron microscopy and embedded in Epon. The Epon blocks were trimmed so as to comprise the middle-third of the buccal periodontal ligament of the mesio-buccal root of the first molar together with some cementum and alveolar bone as landmarks. Two light-gold sections were cut from each trimmed block and systematically photographed in the electron microscope. The photographs were analysed stereologically so as to quantitate phagocytosed collagen (ICC), cytoplasm (CC) and extracellular fibrillar collagen (ECC). The results for the hypofunctional and contralateral control ligaments were compared with each other and with earlier results from similar but untreated (baseline) animals. The results were expressed as mean values for ICC, CC and ECC, and as the ratios ICC/ECC (the fraction of extracellular collagen phagocytosed), ICC/CC (collagen phagocytic activity per unit cytoplasm) and CC/ECC (cell density per unit extracellular collagen fibril). Significant differences were found for all measurements except ICC/ECC which remained the same in the three states of the ligament. The hypofunctional ligaments had the lowest collagen phagocytic activity and the highest cell density, whereas the ligaments from the untreated animals had the highest collagen phagocytic activity and the lowest cell density. The values for the contralateral control ligaments were intermediate between those for the other two states of the ligament. There was also a significant loss of recognizable, extracellular fibrillar collagen in the hypofunctional ligament. It is suggested that this loss of ECC and its replacement by less organized, pre-fibrillar forms of collagen may be an important mechanism in tooth eruption.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D010513	Periodontal Ligament	The fibrous CONNECTIVE TISSUE surrounding the TOOTH ROOT, separating it from and attaching it to the alveolar bone (ALVEOLAR PROCESS).	Alveolodental Ligament,Alveolodental Membrane,Gomphosis,Alveolodental Ligaments,Alveolodental Membranes,Gomphoses,Ligament, Alveolodental,Ligament, Periodontal,Membrane, Alveolodental,Periodontal Ligaments
D010587	Phagocytosis	The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).	Phagocytoses
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D002452	Cell Count	The number of CELLS of a specific kind, usually measured per unit volume or area of sample.	Cell Density,Cell Number,Cell Counts,Cell Densities,Cell Numbers,Count, Cell,Counts, Cell,Densities, Cell,Density, Cell,Number, Cell,Numbers, Cell
D003094	Collagen	A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH).	Avicon,Avitene,Collagen Felt,Collagen Fleece,Collagenfleece,Collastat,Dermodress,Microfibril Collagen Hemostat,Pangen,Zyderm,alpha-Collagen,Collagen Hemostat, Microfibril,alpha Collagen
D003766	Dental Occlusion	The relationship of all the components of the masticatory system in normal function. It has special reference to the position and contact of the maxillary and mandibular teeth for the highest efficiency during the excursive movements of the jaw that are essential for mastication. (From Jablonski, Dictionary of Dentistry, 1992, p556, p472)	Canine Guidance,Occlusal Guidance,Occlusal Plane,Occlusion, Dental,Dental Occlusions,Guidance, Canine,Guidance, Occlusal,Occlusal Guidances,Occlusal Planes,Occlusions, Dental,Plane, Occlusal,Planes, Occlusal
D005347	Fibroblasts	Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.	Fibroblast
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia