Effect of aluminum on the histological structure of rats’ cerebellar cortex and possible protection by melatonin

Background Aluminum (AL) is toxic to the central nervous system, and melatonin (MEL) reduces lipid peroxidation by its antioxidant activity. Objective This study was carried out to investigate the histological changes in the cerebellar cortex of rats after AL treatment and to detect any possible protective role of MEL when given concomitantly with AL. Materials and methods This study used 50 adult male albino rats, randomly divided into five equal groups. Group I: control group; group II: received daily intraperitoneal (i.p.) injection of ½ ml 0.9% saline containing 2% ethanol; group III: received daily i.p. injection of MEL at 10 mg/kg bw dissolved in ½ ml 0.9% saline plus 2% ethanol; group IV: received daily i.p. injection of aluminum chloride at 10 mg/kg bw dissolved in ½ ml saline; group V: received both AL and MEL. After 2 months of treatment, the cerebellum was dissected out from each animal and was processed for light and electron microscopic studies. Morphometric and statistical analysis were conducted. Results After AL administration, the cerebellum exhibited significant reduction in the number of Purkinje cells and prominent perineuronal spaces in the molecular layer around basket and stellate cells. Ultrastructurally, some of the few encountered Purkinje cells were shrunken with dense cytoplasm, ill-distinct nuclei, and swollen mitochondria with ruptured membranes and cristae. Granule cells revealed increased condensation of their nuclear chromatin. Concomitant administration of MEL with AL displayed an observable protection against these changes. Conclusion MEL may have a protective role against AL-induced cerebellar toxicity.