Efeitos do estresse crônico sobre o estado redox e tecidual das glândulas salivares parótida e submandibular: um estudo in vivo

Abstract

Stress is a reaction to mental and emotional pressure, anxiety, or trauma. Chronic stress is defined as constant exposure to such events. It can affect various body systems, increase blood pressure, and weaken immunity, thereby interfering with physiological health processes. From this perspective, several organs may exhibit responses or alterations under conditions of chronic stress. Therefore, this study aimed to evaluate the effects of chronic stress on the salivary glands of rats, investigating their oxidative biochemistry and histomorphological parameters. For this purpose, 32 male albino Wistar rats were randomly divided into two groups: chronic stress and control. The animals in the chronic stress group were subjected to an immobilization protocol, being placed in a polyvinyl tube for 4 hours daily for 28 days, which restricted their movement. Subsequently, the animals were euthanized for the collection of the parotid and submandibular salivary glands. The redox status of the glands was assessed using the antioxidant capacity against peroxyl radicals (ACAP) assay and thiobarbituric acid reactive substances (TBARS) assay. Histological analysis was performed through morphometry of tissues stained with hematoxylin and eosin, and histochemistry using the PicroSirius Red technique. Both the parotid and submandibular glands of the stressed rats exhibited oxidative stress, characterized by a reduction in ACAP levels and an increase in TBARS levels. However, the parotid glands proved to be more susceptible to harmful tissue alterations, such as an increase in stromal area and collagen area fraction, a reduction in acinar area, and smaller size of acini and ducts. In contrast, the submandibular glands did not show any histomorphological alterations. Our results suggest that chronic stress can cause a harmful modulation of the redox status of the salivary glands, with different histological repercussions between the glands.