Effects of long-term dietary intake of magnesium on rat liver transcriptome

In the present study we investigated the effect of a two-year treatment period with a diet containing 3.2g, 0.8 g and 0.15 g Mg/kg, on the rat liver transcriptome. At the end of the study, a treatment-dependent decrease in plasmatic Mg concentration was found (0.86 +/- 0.02 mmoVL, 0.70 +/- 0.02 mmol/L and 0.52 +/- 0.03 mmoVL for groups receiving 3.2g, 0.8 g and 0.15 g Mg/kg diet, respectively). No significant treatment-related effect on body and liver weights was observed, however a dietary Mg intake-dependent increase in mortality rate occurred in animals (11%, 25% and 38% death of animals). Mg content in the diet affected gene expression in rat livers, as assessed by rat specific DNA microarrays. We identified 11 genes up-regulated and 39 genes down-regulated by at least two-fold by a decrease in Mg content and grouped them within five functional pathways: metabolism 20%, cytoarchitecture (connective tissue/cell adhesion/cytoskeleton) 12%, channels/ transporters 20%, turn-over (nucleic acid and protein) 16%, and homeostasis (stress/DNA damage/apoptosis/ageing) 32%. The results of the present study confirm the pleiotropic effects of Mg and provide further evidence that a Mg decrease in the diet may be considered as a promoting factor for pathologies, especially in the liver, during ageing.