Unlike other rodents, organogenesis is shown to be completed during the fetal period in the spiny mice. Rodent submandibular salivary glands are characterized by a highly specialized portion of the ductal system called granular convoluted tubules (GCT), whose secretory cells synthesize a variety of growth factors. These factors may have a functional role in cell migration, proliferation and maturation within not only salivary glands but also other organs. Absence of the granular convoluted tubules from the submandibular gland of laboratory mice in the first week postnatally is documented, and the structure of such gland in the spiny mice has not been mentioned previously. So, The present work aimed to study the structural difference of the submandibular salivary gland in the spiny mice, in comparison to the corresponding age of laboratory mice. Material and Method: Tissue specimens of submandibular salivary gland were collected at the 7 th postnatal day from both species, and then processed for light and electron microscopic examination. Immunohistochemical study using epidermal growth factor (EGF) and chromogranin (CgA) was done. Results: On the contrary to laboratory mice aged one week postnatally, spiny mice submandibular gland of the same age showed well developed secretory unites and ductal system including the GCT. Conclusion: Well developed neonate spiny mice submandibular gland (early appearance of granular convoluted tubules) may refer to the role of growth factors in organogenesis.
Keywords: Spiny mice, salivary gland, neonate