Abstract
Development and maturation of submandibular salivary glands are influenced by intrauterine diabetic environment. Several studies investigated the effects of diabetes on the salivary glands. However, the effects of maternal diabetes on the submandibular glands of the offspring was not properly examined. Therefore, the present study was designed to describe the changes in the development of the submandibular glands of the offspring of diabetic mothers. The submandibular glands of the offspring of Streptozotocin (STZ)-induced diabetic female rats were examined at two and four weeks after birth. Detection of mRNA demonstrated that maternal diabetes affects the level of different indicators. The reduction of expression of epidermal growth factor (EGF); a protein mitogen, cytokeratin 5 (CK5); an epithelial cell progenitor, CK7 and aquaporin 5 (AQP5); differentiation markers and B cell lymphoma 2 (Bcl2); an antiapoptotic marker were found. Increase in Bcl2-associated X protein (Bax); an apoptotic marker was detected. These changes indicate their effects on saliva secretion, glands tumorigenesis, growth of normal oral flora and oral microbes, with decreased protein synthesis and production of xerostomia and dental caries. Loss of normal glandular architecture, significant increase in fibrosis, by the detection of collagen fibers, and stagnation of secretory granules were found with atrophic changes in the acinar cells. Marked defect of polysaccharides in the acinar cells, denoting functional changes, was manifested by significant reduction of the intensity of periodic acid-Schiff (PAS) reaction. The positive immunoreactivity of caspase-3, denoting cellular apoptosis, and minimal reaction of alpha-smooth muscle actin (α SMA) and proliferating cell nuclear antigen (PCNA) were evident in the offspring of diabetic mothers. We conclude that maternal diabetes produces degenerative effects in the structure and function of the submandibular salivary glands of the offspring, reflecting possible influences on their secretory activity affecting oral and digestive health.
Highlights
Development of human salivary glands starts from the fourth week of fetal life and continues after birth [1]
No significant variation in the serum glucose levels of the offspring of all groups was found after labor (Table 3)
Detection of mRNA was performed demonstrating that maternal diabetes significantly reduced the expression of epidermal growth factor (EGF) which is a protein mitogen [29], cytokeratin 5 (CK5) which is an epithelial cell progenitor [30], aquaporin 5 (AQP5) which is an acinar [31] differentiation markers and B cell lymphoma 2 (Bcl2) which is an antiapoptotic marker and significantly increased Bcl2-associated X protein (Bax) which is an apoptotic marker [32] in 2w diabetic group compared with 2w control group (Table 4 and Fig 3) and in 4w diabetic group compared with 4w control group (Table 5 and Fig 3) demonstrating the degenerative effects of maternal diabetes on the development, growth and function of the submandibular salivary glands of the offspring
Summary
Development of human salivary glands starts from the fourth week of fetal life and continues after birth [1]. Maturation of the submandibular salivary glands is influenced by intrauterine and postnatal disturbances. The submandibular glands produce 65% of the total saliva secreted from all salivary glands. Secretion of saliva increases above the resting level by taste and mastication and to a lesser degree by olfaction [4]. Carpenter [3] concluded that the principle stimulus for the flow of saliva are chewing and taste. The antibacterial, antiviral and antifungal components of the saliva help to maintain the normal oral flora [5]. Benn and Thomson [6] reported that submandibular glands secrete viscous saliva composed of 99% water. Submandibular salivary secretion contains neuronal and epidermal growth factors which promote lubrication and protection of gums and oral mucosa. Most calcium in saliva is bound to statherin or to other phosphor-containing proteins that prevents excessive precipitation of calcium on the teeth [7]
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