Melatonin Restricts Periodontitis Related Neurodegeneration in Rats.

OBJECTIVE: This experimental rat study aims to investigate the preventive role of melatonin in potential neurodegenerative changes associated with periodontitis in the hippocampus and cerebral cortex. METHODS: Twenty-four Sprague Dawley rats were divided into three groups: Control (n = 8), Ep (n = 8), Ep + Mel (n = 8). Systemic melatonin (10 mg/kg/day) was administered to the Ep + Mel group for 35 days of periodontitis induction, starting from the application of bilateral lower first molar ligation. Following sacrification of all groups, periodontal bone loss was analyzed in Micro-CT sections (sagittal and coronal). Cerebral cortex and hippocampus tissues and serum samples were analyzed histopathologically, immunohistochemically, and biochemically. RESULTS: Micro-CT results showed that the experimental periodontitis model was successful. When Ep + Mel and Ep were compared, a significant difference was observed in terms of histopathological damage, Caspase-3, GFAP, and Iba-1 immunopositivity (p < 0.05). Systemic melatonin administration was found to significantly reduce tissue and serum levels of IL-1β, IL-1β/IL-10, and Aβ1-42 (p < 0.05). Additionally, serum TNF-α and tissue TOS and OSI levels were significantly reduced in the melatonin group (p < 0.05). Tissue TAS and serum IL-10 showed no significant change (p > 0.05). CONCLUSIONS: This study demonstrated that systemic melatonin may limit periodontal tissue destruction and periodontitis-associated neuroinflammatory, neurooxidative, and neuroapoptotic changes in the cerebral cortex and hippocampus.