Immunohistochemical expression of type II collagen in the lingual mucosa of rats during organogenesis of the tongue.
OBJECTIVE
We examined the timing of the appearance and distribution of type II collagen as a possible component of the extracellular matrix that is involved in the morphogenesis of the rat tongue.


METHODS
We examined the immunofluorescence of type II collagen, differential interference contrast (DIC) images, and images recorded in transmission mode after toluidine blue staining by laser-scanning microscopy (LSM) during the morphogenesis of filiform papillae and the keratinization of the lingual epithelium of rats on semi-ultrathin sections of epoxy resin-embedded samples.


RESULTS
Immunoreactivity specific for type II collagen was scattered on cells over a wide area of the mesenchymal connective tissue of the fetal tongue on day 15 after conception (E15), when the lingual epithelium was composed of one or two layers of cuboidal cells. Immunoreactivity specific for type II collagen was recognisable on cells of the lamina propria of the lingual mucosa and around the developing lingual muscle of fetuses at E17 and E19. On E19, the epithelium was clearly of the stratified squamous type. At postnatal stages after birth (P0), immunoreactivity became more and more significant in the connective tissue of the lamina propria with the advancing of morphogenesis of the filiform papillae. In addition, immunoreactivity was widely distributed in the connective tissue around the lingual muscle, as myogenesis in the tongue advanced. The lingual epithelium was composed of stratified squamous cells, and keratinization of the lingual epithelium proceeded gradually as morphogenesis of filiform papillae continued during postnatal development.


CONCLUSIONS
Type II collagen appeared not only in the connective tissue of the lamina propria as the morphogenesis of filiform papillae occurred and the lingual epithelium became keratinized but also in the endomysium and perimysium around the lingual muscle after myogenesis of the tongue is complete at P0.
Asami
Tomoichiro
T
Gunma PAZ College School of Nursing, Takasaki, Gunma, Japan.
Aoyagi
Hidekazu
H
Yoshizawa
Hideki
H
Wanichanon
Chaitip
C
Iwasaki
Shin-Ichi
S
D000818:Animals; D000831:Animals, Newborn; D024043:Collagen Type II / Q000096:biosynthesis*; D004815:Epidermal Growth Factor / Q000032:analysis; D066246:ErbB Receptors / Q000032:analysis; D005260:Female; D005455:Fluorescent Antibody Technique; D008297:Male; D018613:Microscopy, Confocal; D009061:Mouth Mucosa / Q000196:embryology* / Q000378:metabolism; D038081:Organogenesis / Q000502:physiology*; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014059:Tongue / Q000196:embryology* / Q000378:metabolism
D024043:Collagen Type II; D004815:Epidermal Growth Factor; D066246:ErbB Receptors