Melatonin may be an alternative to amifostine in salivary gland protection in irradiated rats.

BACKGROUND: The aim of this study was to compare the effects of systemic amifostine (Ami) and melatonin (Mel) alone and the combined use of the drugs on apoptotic, oxidative, biochemical and morphometric outcomes caused by radiotherapy (RT)-induced salivary gland injury. METHODS: 40 female Sprague-Dawley rats were divided into 5 groups: Control, RT, RT + Ami, RT + Mel, RT + Ami + Mel. 30 min before single dose 5 Gy RT, Ami (200 mg/kg) was administered for 3 days and Mel (10 mg/kg) was administered for 15 days. Caspase-3 and Ki-67 apoptotic activity markers and NF-Κb/p65, a transcription factor, were analyzed immunohistochemically, and serum inflammatory cytokine (IL-1β, IL-10, IL-6, TNF-α) and oxidative stress (8-OHdG and OSI) levels were analyzed biochemically. RESULTS: The destructive effect of RT on the salivary gland has been clearly demonstrated at the level of histopathological damage, apoptotic activity, oxidative stress and biochemical parameters. When the two drug groups were compared, no statistical difference was found (p > 0.05); Mel prophylaxis provided significant decreases, especially in IL-1β and OSI levels (p < 0.05). With the combined use of both drugs, a slightly synergistic effect at the inflammatory, oxidative and apoptotic levels has been proven. CONCLUSION: Mel has a salivary radioprotective activity comparable to Ami. The combined use of drugs has not provided a significant therapeutic advantage in preventing salivary inflammatory stress and apoptotic changes. Thus, Mel may be an alternative to Ami to prevent RT-induced salivary gland damage.