Localization of FGF-6 and FGFR-4 during prenatal and early postnatal development of the mouse sublingual gland.
A number of fibroblast growth factors (FGFs) are involved in regulatory mechanisms of the salivary gland development. However, the role of FGF-6 unique in myogenic cells has not been elucidated in the developing sublingual gland. In the present study, temporo-spatial expression of FGF-6 and its receptor (FGFR)-4, in conjunction with some related histo-chemical properties, were investigated in the sublingual gland of the prenatal and early postnatal mice. The earliest expression of both FGF-6 and FGFR-4 was detected in immature acinar cells at gestational day 17 (GD17). The staining intensity increased gradually and some acinar cells showed a distinct staining at postnatal day 0 (PD0). The immunopositive cells had a relatively round profile and were assumed to be acinar cells. The positive staining decreased thereafter and disappeared completely by PD11. To confirm the identity of cells positive for FGF-6, double immunolabeling with anti-alphasmooth muscle actin (alphaSMA) and anti-FGF-6 antibodies was performed. The positive staining of alphaSMA, a marker of myoepithelial cells, was detected in the flattened cells surrounding the acini but not in the cells positive for FGF-6. The staining properties of secretory granules in acinar cells were also examined with periodic acid-Shiff (PAS) and alcian blue (AB). PAS-positive granules abundant in the late gestational stages (GD17 to PD0) began to be replaced with AB-positive mucous granules at early neonatal days (PD0-3), when the FGF-6/FGFR-4 expression was the strongest. These findings suggest that FGF-6/FGFR-4 might be involved in the changes of secretory granule content of acinar cells in the sublingual gland during the late gestational and early neonatal stages.
Uehara
Toshitomo
T
Nihon University Graduate School of Dentistry, Tokyo, Japan. uehara-ts@dent.nihon-u.ac.jp
D000818:Animals; D000833:Animals, Suckling / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000737:chemistry; D051522:Fibroblast Growth Factor 6 / Q000032:analysis / Q000096:biosynthesis*; D018507:Gene Expression Regulation, Developmental; D007124:Immunoenzyme Techniques; D051379:Mice; D008815:Mice, Inbred Strains; D051499:Receptor, Fibroblast Growth Factor, Type 4 / Q000032:analysis / Q000096:biosynthesis*; D013361:Sublingual Gland / Q000737:chemistry* / Q000166:cytology / Q000196:embryology* / Q000254:growth & development
D051522:Fibroblast Growth Factor 6; D051499:Receptor, Fibroblast Growth Factor, Type 4