Streptozotocin- induced changes in aquaporin 1 and 4, oxidative stress, and autophagy in submandibular and parotid salivary glands and the possible ameliorative effect of intermittent fasting on these changes.

Salivary glands are highly responsible for maintaining oral tissue homeostasis by secreting saliva. This study was designed to investigate aquaporin 1 and 4, oxidative stress, and autophagy in submandibular and parotid salivary glands of diabetic rats and the possible ameliorative effect of intermittent fasting on these changes. Fifty adult male rats were divided into control and experimental groups. Experimental diabetes was induced by a single intraperitoneal injection of streptozotocin. After induction of diabetics, the experimental group was divided into two groups (diabetic without intermittent fasting and diabetic with intermittent fasting). The animals were sacrificed two and four weeks after induction of diabetes. Intermittent fasting significantly decreased malondialdehyde and significantly elevated reduced glutathione (GSH) in the submandibular and parotid glands compared to those of diabetic rats. The salivary secretions were also significantly histologically spared in diabetics with intermittent fasting groups. Furthermore, intermittent fasting increased aquaporin 1 in both glands, while aquaporin 4 was only elevated in the submandibular gland. The immunolocalization and gene expression of Lc3-II was higher in the diabetic salivary glands than in the fasting glands. In conclusion, these findings highlight the pathological role of autophagy in diabetic submandibular and parotid glands and provide potential target for the therapeutic role of intermittent fasting to ameliorate the dysfunction of the submandibular and parotid glands in type I diabetes mellitus.