Ultrastructural studies of the rat submandibular gland in streptozotocin induced diabetes mellitus

Abstract

Increased fluid intake (polydipsia) is one of the classic symptoms of diabetes mellitus. Xerostomia (dry mouth) and resultant thirst are other symptoms of the disease and bear a close relationship to polydipsia. The xerostomia in individuals with diabetes is primarily due to decreased saliva flow which appears to be associated with degenerative changes in the salivary glands. This study examines the response of the rat submandibular gland to streptozotocin induced diabetes mellitus. Adult male rats were given a single I.V. dose of streptozotocin (65 mg/kg body weight) in citrate buffer (pH 4.5). Salivary glands were examined by light and electron microscopy at 4, 8 and 24 h and 3, 7, 14 and 21 days posttreatment. The changes in the acinar cells were characterized by an accumulation of secretory material within the cytoplasm. This secretory protein accumulation was followed by degenerative changes in the acinar cells which frequently resulted in cell death and replacement of secretory cells by connective tissue elements. The loss of secretory volume and potential changes in secretory kinetics are discussed with regard to the xerostomia, thirst and polydipsia exhibited by individuals with diabetes mellitus.

Effect of Hyperglycemia on the Excretory Ducts of the Submandibular Gland (Histologic Study)

“…Epithelial cell height in these ducts reduced by 10.28 and 10.77% (p<0.01 -0.001) ( Table 1). The disruption of the structural organization of the aforementioned subdivisions of the intralobular duct in the early stages of hyperglycemia development was observed by L. S. Cutler et al as well [25]. At the same time, the authors noted that changes were of a focal nature.…”

Tear film and ocular surface changes in diabetes mellitus

“…In addition, lower and early doses of streptozotocin are able to simulate the conditions of DM type 2 (49) . In diabetic rats, reduced tear film secretion, cataracts and salivary gland dysfunction after 4-5 weeks, corneal epithelia alterations and wound healing delay after 8-10 weeks, and histological damage of retina after 40 weeks are the ocular diseases that have been reported (50)(51)(52)(53) . The possibility that a direct toxic effect of streptozotocin on peripheral tissues would be confounded with diabetic complications was not proven in a recent study with rat lacrimal glands (54) .…”

SGLT1 protein expression in plasma membrane of acinar cells correlates with the sympathetic outflow to salivary glands in diabetic and hypertensive rats

“…Furthermore, in both strains, diabetes reduced the sympathetic nerve activity. Morphological damage to the sympathetic innervation of salivary glands in diabetic rats includes fiber degeneration (5,16) and decreased number and size of fibers (41) as well as focal dilatations of axons and accumulation of subcellular organelles. Additionally, reduced noradrenaline content and release in sympathetic neurons of salivary glands has been described in diabetic rats (40).…”