Stimulating angiogenesis by hyperbaric oxygen in an isolated tissue construct.

ABSTRACT

BACKGROUND: Hyperbaric oxygen (HBO2) treatment has been shown to stimulate angiogenesis in prefabricated myocutaneous flaps. We conducted the current study to determine optimal HBO2 treatment intervals for peak angiogenesis. METHODS: Lewis rats were implanted subcutaneously with silicone molds in the inguinal region. Molds contained inguinal fat, a vascular pedicle and Matrigel plug. Thirty-two animals were randomized into four groups HBO2 Treatment (2.5 atm of 100% oxygen, 90 minutes, 2x/day)--Group 1 (seven days) or--Group 2 (14 days); and Control Treatment (room air at atmospheric pressure)--Group 1 (seven days) or--Group 2(14 days). Implants were harvested, processed for H&E staining, and imaged digitally; angiogenesis was assessed by grade of vascularization at the Matrigel/fat boundary. Intergroup grading differences were assessed statistically. RESULTS: Vascularization in seven-day HBO2-treated implants was significantly increased compared to seven-day controls (p = 0.008). Vascularization in 14-day HBO2-treated implants was significantly decreased compared to 14-day controls (p = 0.012). There was no significant difference between seven-day HBO-treated implants and 14-day controls (p > 0.05). CONCLUSIONS: Short-term HBO2 exposure appears to increase angiogenesis in isolated tissue constructs. Prolonged HBO2 exposure may lead to vascular pruning. Short-term HBO2 exposure appears to expedite the natural vascularization process, resulting in equivalent vascularization in a shorter time.