Effect of hyperoxia on vascular endothelial growth factor levels in a wound model

HYPOTHESIS: Hyperbaric oxygen (HBO) therapy increases vascular endothelial growth factor (VEGF) levels in wounds. DESIGN: Wounds were monitored for oxygen delivery during HBO treatment, and wound fluids were analyzed for VEGF and lactate on days 2, 5, and 10 following wounding. SETTING: Experimental animal model. INTERVENTIONS: Rats were randomized to HBO therapy and control groups. The HBO therapy was administered for 90 minutes, twice daily with 100% oxygen at 2.1 atmospheres absolute. Treatment was administered for 7 days following wounding. MAIN OUTCOME MEASURES: Vascular endothelial growth factor, PO(2), and lactate levels in wound fluid were measured on days 2, 5, and 10. RESULTS: Wound oxygen rises with HBO from nearly 0 mm Hg to as high as 600 mm Hg. The peak level occurs at the end of the 90-minute treatment, and hyperoxia of lessening degree persists for approximately 1 hour. The VEGF levels significantly increase with HBO by approximately 40% 5 days following wounding and decrease to control levels 3 days after exposures are stopped. Wound lactate levels remain unchanged with HBO treatment (range, 2.0-10.5 mmol/L). CONCLUSIONS: Increased VEGF production seems to explain in part the angiogenic action of HBO. This supports other data that hypoxia is not necessarily a requirement for wound VEGF production.