| Research Abstract |
I. In the present study, the effects of both growth factor TGF-α and carcinogen Trp-P-2 on the development of organ-cultured ddY mouse tooth-germ which was transplanted into the subcutaneous tissue of nude mice were investigated histologically, immnohistochemically (PCNA) and histometrically in 5 groups of mice, namely Group A (Control), Group B (DMSO), Group C (TGF-α), Group D (Trp-P-2) and Group E (TGF-α + Trp-P-2). Histologically, in Groups C, D and E, marked proliferation of odontogenic epithelial cells was observed. In Groups D and E, keratinization of the odontogenic epithelial cells was found, but it was not observed in Group C.Moreover, in Group E, a cyst-like space was observed in the area of odontogenic epithelial cells. Immunohistochemically, in Groups C, D and E, PCNA-positivities of the odontogenic epithelial cells were significantly higher than those of Group A.Histometrically, in Groups C and E, the size of the tooth germ was significantly larger in size than that of Gro
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up A. The results of the present study suggest that proliferation, keratinization, cyst-like space formation of odontogenic epitherial cells of transplanted organ-cultured tooth-germs in mice were promoted by growth factor TGF-α and carcinogen Trp-P-2.
II. In the present study, the effects of both carcinogen MeIQx and growth factor TGF-α on the development of organ-cultured ddY mouse tooth-germs were investigated histologically and immnohistochemically (PCNA) in 5 groups of mice, namely Group A (Control), Group B (DMSO), Group C (TGF-α), Group D (MeIQx) and Group E (MeIQx + TGF-α). Histologically, in Groups A and B, both tooth-germs appeared in similar size. In Group C, the tooth-germ was bigger in size than those of Groups A and B. In Groups D and E, the tooth-germs were smaller than in Group C. In Groups C, D and E, marked proliferation of odontogenic epithelial cells was observed. Immunohistochemically, in Groups B, C, F and G, PCNA-positivities of odontogenic epithelial cells were significantly higher than those in Group A. The results of the present study suggested that the proliferation of odontogenic epitherial cells in organ-cultured tooth-germs in mice was promoted by carcinogen MeIQx and growth factor TGF-α.
III. The purpose of the present study was to investigate the effects of growth factor TGF-α and carcinogenen ENU on the development of the transplanted organ-cultured tooth germs in ddY mice. The organ-cultured tooth-germs removed from the 17th day embryo of the ddY mouse were divided into the following 5 groups according their cultured conditions, Group a (Control), Group b (DMSO), Group c (TGF-α), Group d (ENU), and Group e (TGF-α + ENU). These tooth-germs were transplanted into the subcutaneous tissue of the nude mice, and the transplanted organ-cultured tooth-germs were examined histologically and immunohistochemically (PCNA stainings) 2 weeks after transplantation. In Groups c, d and e, proliferation of odontogenic epithelial cells was found in the transplanted organ-cultured tooth-germ. Moreover, in Groups c and e, a cyst-like space was observed in the area of odontogenic epithelial cells. In groups s and e, PCNA-positivities of odontogenic epithelial cells were significantly higherthan that of Group a. The results of the present study indicated that TGF-α and ENU promoted markedly proliferation of odontogenic epithelial cells in the transplanted organ-cultured tooth-germ Less
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