Development of esophageal epithelium in the fetal and neonatal mouse

Abstract

Development of the fetal mouse esophageal epithelium was followed using light microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and radioautography. At 15 days of gestation in the cervical (C), mediastinal (M), and abdominal (A) segments of the esophagus, the epithelium was two or three cells thick, and only cells located in the basal (germinal) layer incorporated tritiated thymidine. Ciliated cells were sparse in all three segments. At 17 days of gestation, longitudinal mesenchymal ridges became more differentiated in the distal segment. Labeling indices were lower than at preceding stages in each segment. Ciliated cells had increased in number and appeared to be evenly distributed along the whole esophagus. In periodic acid-Schiff (PAS)-stained sections, an increasing proximodistal distribution of glycogen stores was observed, with greatest concentrations found in segment A. At 18 days of gestation, labeling indices were comparable in segments C and M (11.7% +/- 2.9% and 12.8% +/- 1.9%, respectively) but remained higher in segment A (17.9% +/- 2.0%). Ciliated cells were still present. At this stage, transverse circular furrows and ridges started to appear. They increased in number at 4 days after birth and were very closely distributed in the adult. In longitudinal sections, these ridges corresponded to projections of stratum granulosum and of the overlying stratum corneum. After birth, ciliated cells desquamated rapidly but some patches were still present at 4 days. At 8 days, the esophageal epithelium was not yet keratinized.

Esophageal development and epithelial homeostasis

“…2) (100). In the following days (E13.5-E17.5) the epithelium gradually becomes more layered until there are around four layers of epithelial cells (71,100). During development there is a gradual conversion of a K8-positive cuboidal epithelium to a K14-positive squamous epithelium.…”

Feeding manipulation elicits different proliferative responses in the gastrointestinal tract of suckling and weanling rats

“…Adult mice submitted to a low-calorie diet showed a decrease in the labeling index of the esophageal epithelium (15). Raymond et al (13) observed that the LI of the abdominal (distal) esophageal epithelium of mouse fetuses (18 days of gestation) is 17.9 ± 2. Similar results were obtained in the present study for 14-and 18-day-old fed rats (15.3 ± 3 and 14.0 ± 4.6, respectively).…”

“…Recently, the ultrastructure of the fetal and neonatal esophageal epithelium of the mouse was described in detail but only the proliferative indices of the fetal epithelium were measured (13).…”

Light microscopic autoradiographic study of DNA synthesis in cecal epithelial cells of aging mice.

“…DNA synthesis by cells in different organs has been investigated by many authors using light and electon microscopic autoradiography (Gao et al, 1992;Kong et al, 1992;Raymond et al, 1991;Ma and Nagata, 1990;Nagata and Usuda, 1986;Pelc and Appleton, 1965;Messier and Leblond, 1960;Leblond and Messier, 1958). In spite of the few reports available concerning the DNA synthesis as studied by autoradiography in colon using human (Arsenault and Menard, 1989;Pritchett et al, 1985).…”

“…Autoradiographic studies of D N A synthesis demonstrated some evident differences in age-related changes by [ jH]-thymidine incorporation into the different organs and tissues (Duan et al, 1993;Hanai, 1993;Gao et al, 1992;Kong et al, 1992;Olea and Nagata, 1992;Raymond et al, 1991;Arsenault and Menard, 1988;Ma, 1988;Nagata and Usuda, 1986;Leblond and Messier, 1958). Although the studies on D N A synthesis (Morita et al, 1994;Arsenault and Minard, 1989;Buts et al, 1983;Eastwood and Trier, 1974;Chang, 1971;Chang and Lablond, 1971a,b) and cell proliferation (Pritchett et al, 1985;James et al, 1982) of colon epithelium have been carried out, little is known regarding the developmental and age-related changes in colon mucosa.…”