In vivo supplementation with coenzyme Q10 enhances the recovery of human lymphocytes from oxidative DNA damage

We investigated the effect of in vitro and in vivo CoQ(10) supplementation on the recovery of lymphocytes from oxidative DNA damage. Furthermore, we investigated whether CoQ(10) supplementation modulates the activity of DNA repair enzymes by using cellular extracts from lymphocytes. Exposure of lymphocytes to oxidizing agents leads to an increase of DNA strand breaks, oxidized purines, and pyrimidines. Enrichment of cells with CoQ(10) prevents DNA strand-break formation and affects the kinetics of repair, which occurs faster in enriched than in native lymphocytes. In contrast, CoQ(10) supplementation neither prevents endogenous formation of oxidized bases nor affects their repair. DNA repair enzyme activity is enhanced by in vivo CoQ(10) supplementation. Changes in the redox state of several transcriptional factors have been proposed as mechanisms regulating cell proliferation and apoptosis. Because CoQ(10) is mainly present as ubiquinol-10, both in plasma and lymphocytes, it can feasibly modulate the intracellular redox potential involved in the regulation of gene expression. The redox mechanism implicated in the enzyme transactivation could explain the property of CoQ(10) to enhance the DNA repair activity and protect DNA from oxidative damage.