Age-related changes in murine CNS mRNA gene expression are modulated by dietary melatonin.

Brain cellular functions decline with normal aging, accompanied by a changing profile of gene expression. Gene array analysis was used to quantitatively estimate messenger RNA (mRNA) expression levels in the cerebral cortex of both young (4-month) and old (27-month) B6C3F1 male mice. A stringent degree of significance was obtained by using multiple gene chips. Out of 12,423 mRNA levels, only 25 changed significantly with age. Nine of these genes coded for inflammatory proteins, all of which were elevated in aged, relative to younger mice. Melatonin (200 p.p.m.) included in the diet of aged animals for 8 wk elevated serum and cortical melatonin and reversed 13 of the 25 genes altered with age. In no case did melatonin potentiate age-related changes in gene expression. The restoration of a more youthful gene profile to brains of aged animals by melatonin, to a large extent, involves reversal of age-induced elevation of basal inflammatory parameters.