OBJECTIVES: To investigate the effects of topical and systemic administrations of melatonin and dexamethasone on facial nerve regeneration. MATERIALS and METHODS: In total, 50 male albino Wistar rats underwent facial nerve axotomy and neurorrhaphy. The animals were divided into 5 groups: control, topical melatonin, systemic melatonin, topical dexamethasone, and systemic dexamethasone. Nerve conduction studies were performed preoperatively and at 3, 6, 9, and 12 weeks after drug administrations. Amplitude and latency of the compound muscle action potentials were recorded. Coapted facial nerves were investigated under light and electron microscopy. Nerve diameter, axon diameter, and myelin thickness were recorded quantitatively. RESULTS: Amplitudes decreased and latencies increased in both the melatonin and dexamethasone groups. At the final examination, the electrophysiological evidence of facial nerve degeneration was not significantly different between the groups. Histopathological examinations revealed the largest nerve diameter in the melatonin groups, followed by the dexamethasone and control groups (p

Tartrazine is used in the pharmaceutical, cosmetic, and food industries worldwide, despite its many toxic effects. The therapeutic effects of crocin (50 mg/kg/day) against tartrazine-induced (500 mg/kg/day) oxidative damage in ileum and colon tissues in rats have been investigated. Malondialdehyde and total oxidant status levels elevated by tartrazine within the ileum and colon tissues were reduced with crocin treatment, while tartrazine decreased antioxidative parameters (glutathione, total antioxidant status, superoxide dismutase, and catalase) were reverted. Tartrazine-induced histopathological changes of ileum and colon tissues were ameliorated following crocin treatment. In conclusion, Tartrazine consumption elicited tissue injury via lipid peroxidation, and crocin ameliorated oxidative injury by its antioxidant and free radical scavenger properties.