Effect of folate supplementation on mitochondrial mass and membrane potential of rat primary hepatocytes treated with oxidants

The aim of this study was to investigate the effects of folate supplementation on mitochondrial mass and membrane potential of rat primary hepatocytes treated with oxidants. Rat primary hepatocytes were obtained by a two-step collagenase perfusion and incubation in medium containing various concentrations of folate (0-1000 μM). Cells were treated with homocysteine (Hcy), Cu ⁺⁺, or menadione, and changes of mitochondrial mass as well as membrane potential were assessed by flow cytometry. After Hcy treatment for 24 h, mitochondrial mass and membrane potential had significantly decreased in rat primary hepatocytes. Folate supplementation could partially normalize the mitochondrial membrane potential of Hcy-treated cells, but did not affect changes in mitochondrial mass. Upon Cu ⁺⁺ treatment, the mitochondrial membrane potential of rat primary hepatocytes was significantly decreased. The decrease in the mitochondrial membrane potential induced by copper ion, was ameliorated by folate supplementation. After menadione treatment, cells became morphologically deformed and began dying. Folate supplementation affect neither the mitochondrial mass nor membrane potential changes in menadione-treated cells. Taken together, folate supplementation has some protective effects on Cu ⁺⁺, and Hcy-induced changes in the mitochondrial membrane potential, but failed to affect mitochondrial mass.