Efeito do resveratrol e das vitaminas C e E em glândulas parótidas de ratos submetidos à radioterapia

Abstract

Xerostomia and hyposalivation are important sequelae of radiotherapy in the head and neck region since the salivary glands are extremely sensitive to the effects of ionizing radiation. The first article of this dissertation comprehends a literature review in which preventive methods of radiotherapy-induced xerostomia such as the use of cholinergic agonist drugs, antioxidant substances, acupuncture, low power laser therapy and submandibular gland transfer were discussed. The second article describes an experimental study with the objective of evaluating and comparing the radioprotective effect of vitamin E, the association of vitamins C and E, as well as resveratrol on morphological changes induced by radiotherapy in the parotid glands of rats. Seventy male Wistar rats were divided into five groups: control group (1.0 mL / kg of saline); Irradiated control group (1.0 mL / kg of saline solution); Vitamin E group (360 mg / kg, 200 IU / mL vitamin E); Vitamin C and E group (100 mg / kg, 200 mg / mL vitamin C and 360 mg / kg, 200 IU / mL vitamin E); Resveratrol group (100 mg / kg resveratrol). Prior to radiotherapy, the animals received one dose per day of the drug corresponding to each group, for three consecutive days, through gavage. The animals were submitted to cobalt-60 teletherapy in the head and neck region (except the control group), in a single session of 20 Gy. They were euthanized seven and thirty days after radiotherapy and the parotid glands were dissected and prepared for morphological evaluation. After seven days there was no significant difference between the groups regarding the presence of acinar disorganization, cytoplasmic vacuolation, changes suggestive of apoptosis and cellular pleomorphism. Thirty days after radiotherapy, in the vitamin E and resveratrol groups the presence of vacuolation was significantly lower in comparison to the irradiated group (p = 0.015). Also during this period, the resveratrol group presented less nuclear pleomorphism in relation to the irradiated group (p = 0.015). In addition, the vitamin E and resveratrol groups had a significantly higher nuclear area in the 30-day evaluation (p = 0.000). According to the results presented, it is possible to suggest that vitamin E and resveratrol attenuated the effects of ionizing radiation on rat parotid acinar cells. Resveratrol appears to have been more efficient compared to vitamin E.