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[Development and maturation of secretory cells in the trachea of human fetuses]
S Moret1, A Lallemand, D Gaillard
1Laboratoire Pol Bouin, Biologie du Développement, CHU, INSERM U 314, Reims.
The number of tracheal epithelial secretory cells and their mucus secretions change during the course of human foetal development. The muco-secretory cells of the respiratory mucus and glands were studied in the trachea in 46 human foetuses with the aid of histochemical techniques, and ultrastructural examination. During the second trimester of pregnancy, the mucosecretory cells are very numerous in the surface epithelium for a transitory period, and secrete as much neutral mucin as acid mucin; these latter were predominantly sulphomucins. The glands appear progressively from the 13th week of development and remain almost exclusively of the mucous type until the second trimester. During the third trimester the serous cells appear but their number remains low. The mucosecretory surface epithelial cells are rare in this trimester but produce the same type of secretions. The role of secretory cells in utero in the foetus is poorly understood. Foetal secretions differ from the normal adult mucus cells but approach them with qualitative and quantitative differences observed in the mucus of irritated bronchi or those with scarring.
The number of tracheal epithelial secretory cells and their mucus secretions change during the course of human foetal development. The muco-secretory cells of the respiratory mucus and glands were studied in the trachea in 46 human foetuses with the aid of histochemical techniques, and ultrastructural examination. During the second trimester of pregnancy, the mucosecretory cells are very numerous in the surface epithelium for a transitory period, and secrete as much neutral mucin as acid mucin; these latter were predominantly sulphomucins. The glands appear progressively from the 13th week of development and remain almost exclusively of the mucous type until the second trimester. During the third trimester the serous cells appear but their number remains low. The mucosecretory surface epithelial cells are rare in this trimester but produce the same type of secretions. The role of secretory cells in utero in the foetus is poorly understood. Foetal secretions differ from the normal adult mucus cells but approach them with qualitative and quantitative differences observed in the mucus of irritated bronchi or those with scarring.