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OBJECTIVE@#To verify the effect of the mutant gene vps4b on the expression of tooth development-related proteins, dentin sialophosphoprotein (DSPP) and collagenⅠ (COL-Ⅰ).@*METHODS@#Paraffin tissue sections of the first molar tooth germ were obtained from the heads of fetal mice at the embryonic stages of 13.5, 14.5, and 16.5 days and from the mandibles of larvae aged 2.5 and 7 days after birth. The immunohistochemical method was used to detect the expression and location of DSPP and COL-Ⅰ in wild-type mouse and vps4b knockout mouse.@*RESULTS@#DSPP and COL-Ⅰ were not found in the bud and cap stages of wild-type mouse molar germ. In the bell stage, DSPP was positively expressed in the inner enamel epithelium and dental papilla, whereas COL-Ⅰ was strongly expressed in the dental papilla and dental follicle. During the secretory and mineralized periods, DSPP and COL-Ⅰ were intensely observed in ameloblasts, odontoblasts, and dental follicles, but COL-Ⅰ was also expressed in the dental papilla. After vps4b gene knockout, DSPP was not expressed in the dental papilla of the bell stage and in the dental papilla and dental follicle of the secretory phase. The expression position of COL-Ⅰ in the bell and mineralization phase was consistent with that in the wild-type mice. Moreover, the expression of COL-Ⅰ in the dental papilla changed in the secretory stage.@*CONCLUSIONS@#Gene vps4b plays a significant role in the development of tooth germ. The expression of DSPP and COL-Ⅰ may be controlled by gene vps4b and regulates the development of tooth dentin and cementum together with vps4b.
Subject(s)
Animals , Mice , ATPases Associated with Diverse Cellular Activities , Genetics , Collagen , Metabolism , Endosomal Sorting Complexes Required for Transport , Genetics , Extracellular Matrix Proteins , Metabolism , Mice, Knockout , Molar , Odontoblasts , Phosphoproteins , Metabolism , Sialoglycoproteins , Metabolism , Tooth GermABSTRACT
Objective: To study the expressions of cell polarity related proteins CDC42 and PAR3 during tooth germ development in the mice, and to discuss their possible roles during tooth development in the mice. Methods: The whole heads were obtained from the mouse embryo on the days 13. 5, 14. 5, 16. 5 and 18. 5 (E13. 5, E14. 5, E16. 5 and E18. 5) and the mice on the postnatal days 1 (PN1) and 5 (PN5). The tissues were fixed in paraformaldehyde, decalcified, dehydrated, embedded in paraffin, and sectioned. The histology of tooth germ was observed by HE staining. The expressions of CDC42 and PAR3 during tooth germ development were detected by immunohistochemistry staining. Results: The HE staining results showed that E13. 5, E14. 5, E16. 5 and E18. 5 were the bud stage, the cap stage, the early and the late bell stage of tooth germ development, respectively; the tooth germ of PN1 mice showed the matured odontoblasts and ameloblasts; the tooth germ of PN5 mice showed the completed tooth crown development. The immunohistochemistry staining results showed that CDC42 expressed in the tooth germ of the mice at E13. 5, E14. 5 and E16. 5; the CDC42 expression at E 18. 5 was reduced compared with E13. 5, E14. 5 and E16. 5; CDC42 mainly expressed in the odontoblasts and ameloblasts of the tooth germ of the mice at PN1 and PN5; PAR3 weakly expressed in the tooth germ of the mice at E13. 5 and E14. 5, and it was increased at E16. 5 and E18. 5. At PN1 and PN5, the expressions of PAR3 were decreased compared with E18. 5. Conclusion: CDC42 and PAR3 participat in the mouse tooth development; during the early stage of tooth germ development, they may be involved in the proliferation and migration of mouse dental germ; during the late stage, CD42 and PAR3 may be involved in the differentiation of the odontoblasts and the ameloblasts, especially in the establishment and maintenance of cell polarity.
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Objective:To study the expressions of cell polarity related proteins CDC42 and PAR3 during tooth germ development in the mice,and to discuss their possible roles during tooth development in the mice.Methods:The whole heads were obtained from the mouse embryo on the days 13.5,14.5,16.5 and 18.5 (E13.5,E14.5,E16.5 and E18.5) and the mice on the postnatal days 1 (PN1) and 5 (PN5).The tissues were fixed in paraformaldehyde,decalcified,dehydrated,embedded in paraffin,and sectioned.The histology of tooth germ was observed by HE staining.The expressions of CDC42 and PAR3 during tooth germ development were detected by immunohistochemistry staining.Results:The HE staining results showed that E13.5,E14.5,E16.5 and E18.5were the bud stage,the cap stage,the early and the late bell stage of tooth germ development,respectively;the tooth germ of PN1 mice showed the matured odontoblasts and ameloblasts;the tooth germ of PN5 mice showed the completed tooth crown development.The immunohistochemistry staining results showed that CDC42 expressed in the tooth germ of the mice at E13.5,E14.5 and E16.5;the CDC42 expression at E 18.5 was reduced compared with E13.5,E14.5 and E16.5;CDC42 mainly expressed in the odontoblasts and ameloblasts of the tooth germ of the mice at PN1 and PN5;PAR3 weakly expressed in the tooth germ of the mice at E13.5 and E14.5,and it was increased at E16.5 and E18.5.At PN1 and PN5,the expressions of PAR3 were decreased compared with E18.5.Conclusion:CDC42 and PAR3 partieipat in the mouse tooth development;during the early stage of tooth germ development,they may be involved in the proliferation and migration of mouse dental germ;during the late stage,CD42 and PAR3 may be involved in the differentiation of the odontoblasts and the ameloblasts,especially in the establishment and maintenance of cell polarity.
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Objective:To investigate the temporal and spatial distrib ut ions of collagenⅠ and Ⅲ during mouse tooth germ development and their function s during tooth mineralization.Methods:Immunohistochemistry stain ing technique was used to test the expressions of collagen Ⅰ and Ⅲ during mous e tooth germ development. Results:collagen Ⅲ was positive in or al epithelial cells in bud stage,in oral epithelial cells and in stellate reticu lum cells in cap stage. During bell and differentiation stage,collagen Ⅲ was positive in oral epithelial cells, stellate reticulum cells, dental papilla cell s and dental sac cells. During P2-10 d(crown development stage), collagen Ⅲ was expressed possitively in ameloblasts,enamel matrix,odontoblasts,predentin, dental papilla cells,dental sac cells and pulp tissues. During P10-30 d(toot h root development stage),collagen Ⅲ was strongly positive in Hertwig's epithe lial root sheath, cementum, alveolar bone and periodontal ligament cells apart f rom above mentioned cell types. CollagenⅠ was not expressed in bud stage and wa s positive in oral epithelial cells,stellate reticulum cells in cap stage. Durin g bell and differentiation stage,collagen Ⅰ was positive in oral epithelial ce lls, stellate reticulum cells, dental papilla cells and dental sac cells.After P2 d (crown and root development stage), the distribution and expression of co llagen Ⅰ were similar to those of collagen Ⅲ.Conclusions:Coll agenⅠand Ⅲ are involved in tooth germ and tooth tissue development. But the fu nction of collagenⅢ is more extensive than that of collagenⅠ.
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Objective:To investigate spatiotemporal expression of ADAM28 in mouse tooth germ development.Methods:Immunohistochemistry and image analysis technique were used to observe the expressions of ADAM28 at mouse tooth germ development stages.Results:Different expression levels of ADAM28 at tooth germ development stages were observed.At cap stage,ADAM28 was found strongly positive in oral epithelial,stellate reticulum cells of enamel organ,basement membrane,dental papilla cells and dental sac cells.At late bell stage,positive staining was found in ameloblasts,enamel matrix,epithelial root sheath and dental papilla cells.At crown and root development stage,positive staining for ADAM28 was detected in ameloblasts,odontoblasts,cementoblasts,epithelial root sheath,dental papilla cells and dental sac cells.Conclusion:ADAM28 participates in crown and root morphogenesis process ranging from bud stage to late bell stage and from matrix secretion to sclerous tissue formation.It might play an important role in early formation,proliferation and differentiation of odontogenic mesenchymal cells.
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Objective:To observe the temporal and spatial expression and function of mcpr1 gene during murine tooth germ development.Methods:The expression of MCPR1 at different stages of mouse tooth germ were detected by immunohistochemical staining.Results:MCPR1 expression was detected at all stages of tooth germ, but the distribution patterns at various stages were different. It indicated that the temporal and spatial expression pattern of MCPR1 during murine tooth germ development was specific.Conclusion:mcpr1 might play an important role in modulating the differentiation and mature of enamel organ.
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In order to elucidate the developmental stages of human tooth germ during prenatal period, we examined 254 normal fetuses ranging in gestational age from six weeks to fourty weeks old histologically. Lim's developmental pattern of prenatal tooth germ was divided into three groups, the first group consisting of five grades (I, II, III, IV, V) was for the development of enamel epithelium the second group of three grades was for the deposition of dentin matrix and enamel matrix, and the third group of three grades (A, B, C) was for the growth of perifollicular bone. Some developmental progress between enamel epithelium and dental papilla could be identified by observation of the sequential development of deciduous and permanent tooth germs histologically. The following results were made. 1) The prenatal development of tooth germ showed similar weekly stages in both the maxilla and the mandible. The initial deposition of dentin matrix and enamel matrix (III-1 stage) started at 12-14 weeks of gestational age in the deciduous incisor and canine, and at 16-20 weeks of gestational age in the deciduous molars. And the initial deposition of dentin matrix and enamel matrix in the permanent first molar was at 20-22 weeks of gestational age, and that of the permanent incisor was at 34-36 weeks, and that of the permanent canine was 36-38 weeks, and of the permanent premolar was at 38-40 weeks. 2) The S-shaped curvature was characteristically found where the reciprocal induction of odontoblast and amelobast occurred actively in the developing tooth germ. Primarily pre-ameloblasts which abutted on the dental papilla differentiate the condensed mesenchymal cells into odontoblasts, and secondarily matured odontoblasts which bulged into enamel epithelium produced dentin matrix and differentiated the shrunken pre-ameloblasts into ameloblasts. 3) The mandible grew more rapidly than the maxilla during the early prenatal period. The trabecular bone from both jaws proliferated initially into labial side of developing tooth follicle and gradually circumscribed the tooth follicle lingually and mesio-distally, to form perifollicular bone resultantly.
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HumansABSTRACT
Objective To study the tooth germ development of mouse molar in fluorosis.Methods We established an acute fluorosis model and used HE-staining after preparing specimens of different stage of mouse first molar developing tooth germ.Results The developing molars of the control fetuses were at the bell stage of odontogenesis,whereas those of the experimental population were at cap stage.The ameloblasts became shorter and lost polarity.The arrangement of ameloblasts fell into disorder at the bell of differeiational stage and secretory stage.Conclusion The developing molars of the experimental fetuses were retarded.High-dose fluoride has a strong effect in the ameloblasts at the bell of differetiational stage and secretory stage.