Abstract:
The aim of this study was to examine the
effects of melatonin on ionized radiation-induced salivary
gland damage using an experimental model.
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)).
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.
Melatonin may have a significant protective
effect on salivary gland damage secondary to
ionizing radiation.
