Development of the conducting airway epithelium in fetal Syrian golden hamsters during normal and diabetic pregancies

Abstract

The conducting airway epithelium of fetal Syrian golden hamsters was studied from gestational day 12 to day 15, during normal and uncontrolled diabetic pregnancies. Diabetes was induced in the pregnant hamsters by injecting streptozotocin at 60 mg/kg body weight, subcutaneously, early on gestational day 10. Cells in S-phase were labelled immunochemically with bromodeoxyuridine (BrdU), and the day on which endocrine cells and ciliated cells first appeared was determined. In control fetuses, the BrdU-labelling indices (LI's) of different anatomical airway levels were significantly different from one gestational day to the next. For example, the LI of the lobar bronchus was significantly different on each gestational day (P less than .0001), and the same was true of the bronchioles. Moreover, the difference between LI's of the lobar bronchus and bronchioles-terminal buds was highly significant on day 12 (P less than .0001), and on day 13 the differences between lobar bronchus and bronchioles, lobar bronchus and terminal buds, and bronchioles and terminal buds were also highly significant (P less than .0001). However, on gestational days 14 and 15, the LI's were reduced and were comparable at different airway levels. The BrdU-labelling indices were very consistent among fetuses of the same age, and the differences between the average LI's for pups of different litters was numerically very small. Hyperglycemia (mild, moderate, severe) did not alter LI's in the fetal airway epithelial cells. Furthermore, although glycogen was not depleted from the airway epithelium of the hyperglycemic fetuses as it was in the controls, the endocrine cells first appeared on gestational days 12, 13, and 14, respectively, in the trachea, lobar bronchus and bronchioles, followed 1 day later by the ciliated cells, in the fetuses of control and diabetic mothers. In our experimental model, induction of diabetes in the pregnant hamsters on gestational day 10 did not appear to alter development or differentiation of the fetal conducting airway epithelium.

Cytodynamics of in vitro developing airways and interaction with extracellular matrix proteins

“…However, using autoradiographic studies, subsequent observers were able to detect a higher level of labeling of the epithelium of branches from the trachea which was induced by bronchial mesenchyme and a concomitant decrease of labeling of the tracheal epithelium [9]. McDowell et al [14] found evidence of differential labeling of airways by time and localization during culture (peripheral airways labeled more than intermediate airways, which also labeled more than central airways. With time, in organ culture labeling became less, as did the differences in topographic labeling.…”

Spatiotemporal Immunolocalization of Stage-Spacific Embryonic Antigen-1 and Related Antigens in the Developing Trachea and Lung of Fetal Hamsters.

“…The trachea and lung of fetal hamsters have been the subject of studies aimed at understanding normal development and cell differentiation of airway epithelia [11,17,18,25,29,30], partly because the short gestational period peculiar to hamsters affords daily definite morphological changes in the airway epithelium and partly because a variety of studies of the development of lung tumors [21,24] and cell regeneration studies after injury [2,16] have been performed in these animals. Fetal development in the respiratory tract proceeds in a proximal to distal direction in humans and animals, starting in the trachea and progressing to include bronchi, bronchioles and alveoli [3, 13,28,31], and in hamsters (term; 16 days), morphological changes occur on a daily basis in the epithelia at different levels [17,25].…”