Therapeutic potential of coenzyme Q(10) in mitochondrial dysfunction during tacrolimus-induced beta cell injury

We previously reported that oxidative stress induced by long-term tacrolimus treatment impairs mitochondrial function in pancreatic beta cells. In this study, we aimed to investigate the therapeutic potential of coenzyme Q(10), which is known to be a powerful antioxidant, in mitochondrial dysfunction in tacrolimus-induced diabetic rats. In a rat model of tacrolimus-induced diabetes mellitus, coenzyme Q(10) treatment improved pancreatic beta cell function. The administration of coenzyme Q(10) improved insulin immunoreactivity within islets, which was accompanied by reductions in oxidative stress and apoptosis. Assessment of the mitochondrial ultrastructure by electron microscopy revealed that coenzyme Q(10) treatment increased the size, number, and volume of mitochondria, as well as the number of insulin granules compared with that induced by tacrolimus treatment alone. An in vitro study using a pancreatic beta cell line showed that tacrolimus treatment increased apoptosis and the production of mitochondrial reactive oxygen species, while cotreatment with coenzyme Q(10) effectively attenuated these alterations. At the subcellular level, tacrolimus-induced impairment of mitochondrial respiration was significantly improved by coenzyme Q(10), as evidenced by the increased mitochondrial oxygen consumption and ATP production. Our data indicate that coenzyme Q(10) plays an important role in reducing tacrolimus-induced oxidative stress and protects the mitochondria in pancreatic beta cells. These findings suggest that supplementation with coenzyme Q(10) has beneficial effects in tacrolimus-induced diabetes mellitus.