Intermittent fasting preserves the function and histological structure but induces oxidative stress in the salivary glands of male Wistar rats

Studies indicate that dietary patterns influence the function and redox balance of salivary glands. This study examined the effects of intermittent fasting (IF) on the function, histological structure, and redox balance of the salivary glands. Twenty 12-week-old male Wistar rats were randomized into two groups: ad libitum (AL), with continuous access to water and chow, and IF, subjected to 24-h fasting on alternate days for 12 weeks. At the end, pilocarpine-induced saliva was collected to analyze flow rate and biochemical composition, while histological structure and redox balance were assessed in the parotid and submandibular glands. IF reduced final body weight and the absolute weight of the submandibular gland while increasing the relative weight of the parotid gland. Salivary flow rate and biochemical parameters, including pH, buffering capacity, amylase, total protein, and electrolyte concentration, were similar between groups. The areas of acini, ducts, and stroma, as well as total oxidant status and markers of lipid and protein oxidative damage, did not differ between groups in either salivary gland. However, IF distinctly affected the antioxidant defense mechanisms of the salivary glands, reducing total antioxidant capacity and increasing catalase (CAT) activity in the parotid glands, while in the submandibular glands, there was higher CAT activity accompanied by reduced superoxide dismutase, glutathione peroxidase, total antioxidant capacity, and reduced glutathione concentrations. Although IF preserved the function and histological structure of the salivary glands in rats, alterations in antioxidant defense indicate oxidative stress.