Although due to some technical issues, Dnmt1 silencing could not be confirmed in the target cells, and off-target effects of the Dnmt1-siRNA could not be investigated, administration of siRNA ameliorated diabetes-induced increase in gene transcripts and activity of Rac1 and ROS levels; the values obtained from the retinal microvessels prepared from the diabetic mouse eye receiving Dnmt1-siRNA were significantly different from those obtained from the eye receiving siRNA negative control (Figs. 5c, 5d). This evidence concerns the gene DNMT1 and diabetes mellitus.