Discipline: Veterinary Medicine
The influence of the submandibular salivary glands on the lactating mammary gland was determined by examining the effect of total surgical removal of the submandibular salivary glands (total submandibular sialoadenectomy) on the measurements and morphology of the lactating mammary gland of rats. Thirty sexually mature female Sprague-Dawley rats were used in this study. They were divided into three experimental groups namely: intact, sham operated and sialoadenectomized. The mammary glands of lactating intact, sham-operated and sialoadenectomized rats were collected, measured (weighting, length and width in mm), processed using the paraffin technique and stained with H & E, Masson's trichrome and Weigert's stain to observe their morphologic characteristics. Measurements showed that the mammary gland of sialoadenectomized rats only differed significantly in length from those of the intact and sham-operated rats. Histological examination also revealed that the sialoadenectomized rats presented a distinctly different morphology of the mammary gland such as the presence of a thicker capsule, abundant adipose tissue and a less extensive parenchyma with very few secretory alveoli devoid of milk secretion and corpora amylacea. Furthermore, the lumens of the secretory tubules and interlobular ducts of the sialoadenectomized rats were constricted. The results of this study suggest that the submandibular salivary glands, the major source of EGF in rats, influence the morphologic development of the mammary gland for lactation.