Wound healing with hyperbaric oxygen. Experimental study of the angiogenesis phase in the rat.

Hyperbaric oxygen therapy (HBO) is widely reported as highly favourable to wound healing. The experimental models generally used to investigate its ef fects are difficult to set up and reliable quantification of the results ob tained is rarely achieved. The underlying pathophysiological mechanisms occ urring during HBO remain poorly understood and its mode of application for clinical practice is difficult to standardise. Our study was carried out to assess the contributions of oxygen and hyperbaric pressure on the initial steps of wound healing. It was based on qualitative and quantitative analys is of the development of the angiogenic process in a granulation tissue bud , using animals implanted with fibrin chambers, an in vivo model initially described by Dvorak in guinea pigs. In our study, rats were further submitt ed to HBO (OHB group) or hyperbaric air (Air-BB group) treatments. The cont rol group (Control group) consisted of rats maintained in the treatment lan k under normal atmospheric conditions. Nine specific parameters were determ ined and analysed during the course of the angiogenic process by classical histological techniques. The vascular density and the height of the bud wer e particularly examined at day 7, 14 and 21 following chamber implantation. At D7 the neovessel density and bud height were significantly higher in OH B group than in Air-MB or Control groups, thus confirming the beneficial ef fects of this treatment on the initial steps of wound hearing. Nevertheless , the results reported herein also suggest a possible inhibitory effect of hyperbaric therapy alone on this very early process, although the pathophys iological significance of this effect on wound healing remains to be determ ined.