Immunolocalization of fibronectin and collagen types I and III in human fetal parotid and submandibular glands

We examined the distribution of fibronectin and Collagen types I and III in human fetuses under a confocal laser scanning microscope using immunohistochemical staining (at 16, 20, 24, 28, 32 weeks' gestation). The Collagen types I and III form the collagenous matrix components in the connective tissue of the parotid and submandibular glands. These extracellular matrix components were detected at various stages around the terminal portion and in the capsule-like connective tissue of the parotid and submandibular glands. However, the extracellular matrix components in the connective tissue around the terminal portion had a stronger reaction than those in the capsule-like connective tissue found on the fringe of the terminal portion. The Collagen type I of the parotid gland at 16 weeks'gestation had a weaker reaction than that of the submandibular gland. When results of the reaction at other stages and other extracellular matrix components of the two salivary glands were compared, Collagen type I appeared as early as at 16 weeks' gestation in either gland. Since Collagen type I serves as the core connective tissue, these observations suggest that the formation of connective tissue around the parotid gland occurs before or after 16 weeks'gestation lagging behind that of the submandibular gland. Copyright (C) 2003 S. Karger AG, Basel.