Comparison of Intratympanic Oxytocin and Dexamethasone in Cisplatin Ototoxicity: An Experimental Study.

Although it is widely used, there is still no valid treatment for ototoxicity caused by the antineoplastic drug cisplatin. In this study, we aimed to investigate the efficacy of intratympanic resveratrol and intratympanic dexamethasone treatment in cisplatin-induced ototoxicity. We also compared intratympanic atosiban (oxytocin antagonist) and oxytocin in cisplatin ototoxicity. In this study, 30 rats (60 ears) were used by separating into 5 groups. Cisplatin, oxytocin, dexamethasone, atosiban and 0.9% NaCl were administered intraperitoneally to all groups separately. Auditory Brainstem Response and Distortion Product Otoacoustic Emission tests were performed on all groups before and 72 h after the procedure. Pre-treatment values were higher than post-treatment values in all groups (p < 0.001). There was no significant prolongation of the post-treatment Auditory Brainstem Response I-IV interval in the oxytocin and dexamethasone groups (p > 0.05). There was no significant decrease in the frequencies of 2832 and 4004 after treatment in the oxytocin and dexamethasone group compared to pre-treatment in Distortion Product Otoacoustic Emission. As a result, it has been shown that intratympanic oxytocin may be an option that can be used in the treatment, although it is not as effective as dexamethasone in preventing cisplatin ototoxicity.

Melatonin's protective effect on the salivary gland against ionized radiation damage in rats.

OBJECTIVES: The aim of this study was to examine the effects of melatonin on ionized radiation-induced salivary gland damage using an experimental model. MATERIALS AND METHODS: Thirty-two rats were randomized into four groups: (i) the control group (C, n = 8) that received intraperitoneal (i.p.) 0.9% NaCl; (ii) the melatonin group (M, n = 8) that received i.p. 5 mg/kg melatonin; (iii) the radiotherapy group (RT, n = 8) that underwent irradiation; (iv) the melatonin plus radiotherapy group (M+RT, n = 8) that received i.p. 5 mg/kg of melatonin, followed by irradiation 30 min later; and (v) the radiotherapy plus melatonin group (RT+M, n = 8) that received irradiation followed by i.p. 5 mg/kg of melatonin 30 min later. The medications and irradiation were administered for 5 days and the salivary glands of the rats were excised 10 days later; the histopathological changes in the salivary glands were assessed and biochemical analyses were conducted (tissue levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI)). RESULTS: Regardless of whether melatonin was administered before or after radiotherapy, melatonin decreased the radiation-induced parotid and submandibular histological damage. In addition, regardless of whether administration occurred before or after radiotherapy, melatonin decreased oxidative stress markers, such as MDA, TOS, and OSI. On the contrary, levels of antioxidative markers, such as CAT and GPx, were increased by melatonin. CONCLUSIONS: Melatonin may have a significant protective effect on salivary gland damage secondary to ionizing radiation.