Methods:We created 6-mm circular, full-thickness stented wounds on non-diabetic, obese mice (TallyHo/JngJ, n=30) and non-obese controls mice (SWR/J, n=30). Wound healing was assessed photometrically on days 0, 7, 10, 14 and until wound closure. Wound were harvested at each time point for ELISA, RT-PCR and immunohistochemistry analysis. Blood was drawn following a previously established protocol and murine peripheral endothelial progenitor cells (EPCs) counts were quantified with FACS analysis at day 0, 7, 14 and 21.
Results:Obese mice wound healing was significantly delayed (23±2.5 days vs 14±1.5 days). EPC numbers were significantly decreased in the obese goup during the acute ischemic timeframe (7-14 days). CD 31 staining showed significant decreased new blood vessel formation (276.3 ± per LPF vs. 453.7 ± per LPF) among the obese mice (p<0.05). RT-PCR and Elisa analysis showed a significant decrease of angiogenic factors (e.g VEGF, HIF-1 and SDF-1) and anti-apoptotic genes (e.g. Bcl-2) at all timepoints compare to controls(p<0.05). Preliminary analysis of p53 and reactive oxygen species levels in obese wounds showed increased levels compare to controls (p<0.05).
Conclusions: Our data suggest that obese delayed wound healing is related to a vasculogenic impairment involving EPCs. Important angiogenic factors, such as SDF, suggest an signal impairment for the mobilization of EPCs.