Enhancement of wound healing by hyperbaric oxygen and transforming growth factor beta(3) in a new chronic wound model in aged rabbits

Hypothesis: Although hyperbaric oxygen (HBO) has been used clinically for 3 decades, there have been few controlled clinical trials. Animal models hav e not been adequate to test the efficacy of HBO in the treatment of chronic wounds, either by itself or in combination with growth factors. We hypothe size that HBO is as efficacious as a prototype growth factor in improving w ound healing in a new animal model of ischemic chronic wounds. Design: Twenty-five aged rabbits and 3 young rabbits had their ears rendere d chronically ischemic and ulcers were created down to the level of cartila ge. These ulcers were treated in 1 of 3 ways: with HBO, 90 minutes per day, Monday through Friday, for 3 weeks; with transforming growth factor beta(3 ) at 1 mu g/cm(2); or with both modalities combined. Controls were treated with vehicle or hyperbaric room air or both. Results: This model created an aged/ischemic wound that failed to heal spon taneously up to LO; days after wounding (88% reduction compared with aged/n onischemic controls). Hyperbaric oxygen alone and transforming growth facto r beta(3) alone both improved healing rate (only 38% reduction in healing c ompared with aged/nonischemic controls). Combined therapy produced no addit ional improvement over either modality by itself. Conclusions: In aged animals, HBO and transforming growth factor beta(3) we re equally effective in improving wound healing, Our data suggest that HBO alone may be more effective in the chronic wound than in the acute wound. T here was no additive benefit to combining modalities as has been reported i n the same wound model in young rabbits.