A Histological Study of Elastic Fibers in Rat Submandibular Gland and Sublingual Gland

Abstract

Change in the structure of the elastic fibers of the submandibular and the sublingual glands were investigated histologically by using Sprague-Dawley rats aged 0 day to 78 weeks. These samples were stained with Lithion-carmin for nucleus staining and Weigert's resorcin-fuchsin for elastic fiber staining. All stained sections were observed under a transmitted light microscope. Elastase treatment was performed to confirm the existence of the elastic fiber.
Among the acini of the submandibular and sublingual glands, the slight thin elastic fibers invaded from the interlobular connective tissue were observed in 1 to 78 weeks-aged rats. The fibers were not observed at the intercalated ducts of both glands. The elastic fibers around the striated ducts first appeared in the submandibular gland on 9 weeks and in the sublingual gland on 1 week after birth. The fibers were observed clearly in the sublingual gland rather than in the submandibular gland. The elastic fibers around the interlobular excretory ducts were revealed in the submandibular and the sublingual glands on 1 week after birth. The number of the fibers increased in the sublingual gland from 5 weeks and in the submandibular gland from 26 weeks after birth. The elastic fibers around the striated and the interlobular excretory ducts appeared early in the sublingual gland earlier than in the submandibular gland. In the extralobular large ducts, the fibers revealed in the submandibular gland from 1 week and in the sublingual gland from 0 day after birth. The numerous elastic fibers were observed in both glands from 3 to 78 weeks after birth. There was an increase in the elastic fibers by aging in the submandibular and the sub-lingual glands. The structure of the elastic fibers showed the various shapes ; a straight line, curve, granulation, meandering, undulation, coil, ramification and bundle.