S. Deeney1,2, C. Zgheib1,2, J. Xu1,2, J. Hu1,2, T. M. Crombleholme1,2, K. W. Liechty1,2 1University Of Colorado Denver,Center For Fetal And Regenerative Biology,Aurora, CO, USA 2Children’s Hospital Colorado,Department Of Surgery,Aurora, CO, USA
Introduction:
Diabetic impaired wound healing occurs in part due to high levels of oxidative stress. NADPH oxidase 2 (NOX-2) is an inflammatory enzyme involved in superoxide generation; levels of NOX-2 are indicative of tissue levels of oxidative stress. We previously showed that Stromal-derived factor-1α (SDF-1α) levels are decreased in diabetic wounds, that inhibition of SDF-1α increases time to diabetic wound healing, and that treatment of diabetic wounds with SDF-1 α reduces time to epithelialization. The mechanism by which SDF-1α enhances diabetic wound healing has yet to be fully elucidated. We will test the hypothesis that SDF-1α treatment enhances diabetic wound healing by reducing the high oxidative stress associated with diabetic impaired wound healing, as measured by wound tissue NOX-2 levels.
Methods:
Single dorsal full-thickness wounds were created with an 8-mm punch biopsy in C57BKS.Cg-m/Leprdb Db/Db diabetic (n=6) and Db/+ non-diabetic (n=10) mice. Subsets of diabetic and non-diabetic wounds were treated with a lenti-virus expressing SDF-1α (Db/Db n=3; Db/+ n=5) or GFP control (Db/Db n=3; Db/+ n=5). Wounds were harvested 7 days following injury. NOX-2 levels expressed in the wounds were assessed by quantitative real time PCR.
Results:
Wounds in diabetic mice demonstrated significantly elevated levels of NOX-2 compared to those in non-diabetic mice 7 days following wounding (p=0.03). When treated with SDF-1α, wounds of diabetic mice expressed significantly decreased levels of NOX-2 compared to GFP treated wounds of diabetic mice (p=0.04). This indicates that diabetic wounds carry a higher burden of oxidative stress one week after injury than non-diabetic wounds, and that treatment with SDF-1α leads to a decrease in oxidative stress.
Conclusion:
These findings provide evidence that the oxidative stress observed in diabetic wounds can be significantly reduced by SDF-1α treatment as measured by the decrease in NOX-2 levels. This may be a mechanism by which SDF-1α enhances wound healing. Further studies in this area are warranted to elucidate the mechanisms by which SDF-1α reduces NOX-2 expression.