The effects of diethyldithiocarbamate, a SOD inhibitor, on endothelial function in sedentary and exercised db/db mice

The study was designed to evaluate the effects of diethyldithiocarbamate (DDC), an superoxide dismutase (SOD) blocker on endothelial function in db/db mice. The db/db and wild-type (WT) mice were randomly divided into low intensity exercise, moderate intensity exercise and control (sedentary) groups. Mice were exercised daily, 5 days per week. After 6 weeks, ring segments of aortae were mounted in wire myograph and acetylcholine (ACh) concentration response curves were recorded in absence or presence of DDC and DDC plus SOD. Results showed that ACh concentration response curve was similar in WT and WT exercised groups. Incubation of aorta rings of WT mice with DDC suppressed the maximum ACh response (p<0.05). Subsequent incubation with SOD restored vasodilatory response in WT mice. The vasodilatation to ACh was significantly reduced in sedentary db/db mice compare to WT (p<0.05) and incubation with DDC did not further decrease this response, however, addition of SOD restored the vasodilatation to ACh to that observed in WT mice. Mild and moderate exercised db/db mice had ACh response similar to that in WT mice. Incubation with DDC incubation reduced ACh induced vasodilatation and addition of SOD restored this response. Our results support the conclusion that SOD mimetics can be used to improve superoxide-mediated endothelial dysfunction in diabetic db/db mice.