Early-Life Minocycline Exposure Produces Sustained Redox Modulation but Persistent Locomotor Deficits in Drosophila melanogaster

1. Minocycline has shown therapeutic potential in neurodegeneration and ageing, but the effects of exposure during development remain poorly understood. This study investigated whether minocycline exposure restricted to development alters redox status and locomotor function in adult Drosophila melanogaster after drug withdrawal.2. A preliminary adult survival assay was used to inform dose selection. Fly eggs were cultured on standard food containing minocycline at 0.05, 0.10 or 0.20 mM from embryonic development through eclosion. Adults were then transferred to untreated food and assessed on post-eclosion day 5. Larval feeding and body-wall contraction were assessed as developmental behavioural endpoints, adult climbing performance was assessed using the negative geotaxis assay, and redox status was evaluated using FOX-reactive peroxides, nitric oxide-related measures, thiols and malondialdehyde.3. Developmental minocycline exposure reduced FOX-reactive peroxide and nitric oxide-related measures and increased thiol levels in adults. Exposure also impaired larval feeding and adult climbing performance, whereas pupation and larval crawling were not significantly altered.4. Developmental minocycline exposure was associated with altered redox status and locomotor deficits that remained evident in early adulthood following drug withdrawal. These findings support further investigation of the tissue-specific and molecular mechanisms underlying the effects of developmental minocycline exposure.