Abstract
ABSTRACTPurpose:To evaluate the effect of hyperbaric oxygenation (HBO) on angiogenesis in random rat skin flaps, by immunoexpression of vascular endothelial growth factor A (VEGF-A).Methods:Forty adult rats were divided into four groups: GE) epilated; GE/HBO) epilated subjected to HBO; GER) epilated submitted to dorsal skin flap; GER/HBO) epilated subjected to dorsal skin flap + HBO. HBO was performed with rats inside a chamber under atmosphere close to 100% oxygen and pressure of 2.4 absolute atmospheres, 2h per day during seven consecutive days. GE and GER groups were placed in the hyperbaric chamber without HBO. Then, under anesthesia, skin flaps were removed and separated into three portions relative to pedicle fixation. The samples were fixed in formalin and processed for paraffin embedding. Histological sections were submitted to immunohistochemistry for VEGF-A detection. The number of immunostained-blood vessels were counted under light microscopy.Results:GE and GE/HBO groups showed normal and similar skin morphology in the three flap portions. A fibrin-leukocyte crust, along with denatured collagen and intense leukocyte infiltrate, was mainly observed in the dermis of the medial and distal flap portions of GER group. Meanwhile, the GER/HBO group presented more regions with intact collagen and small areas of leukocyte infiltrate in the three flap regions. VEGF-A-immunostained blood vessels were largely seen in all regions of GE and GE/HBO groups, whereas no significant differences were found between these groups. A decrease in vascularization was noticed in GER and GER/HBO groups, which was more evident in the most distal portion of the flaps. However, the number of VEGF-A-immunostained blood vessels in GER/HBO group was significantly higher when compared to GER group.Conclusions:Hyperbaric oxygenation was associated with increased angiogenesis and improved viability of rat skin flaps.
Highlights
Injuries to the integumentary system with loss of substance, from different causes, can be treated with the use of skin flaps
vascular endothelial growth factor A (VEGF-A)-immunostained blood vessels were largely seen in all regions of GE and GE/Hyperbaric oxygen therapy (HBO) groups, whereas no significant differences were found between these groups
The groups submitted to skin flaps (GER and GER/HBO) presented keratinized stratified epithelium and papillary and reticular dermis rich in leukocytes, in the proximal portion
Summary
Injuries to the integumentary system with loss of substance, from different causes, can be treated with the use of skin flaps. Optimizing the feasibility of surgical flaps has always been a challenge in medical science. McFarlane et al.[8] standardized an experimental model in rats to assess the viability of random flaps. They concluded that biochemical and morphological changes take place according to the distance from the tip of the flap to its bottom (pedicle). The presence of hematoma and edema, and the relation of the pedicle width versus skin flap area itself can lead to necrosis of the distal portion of the flap to the pedicle in percentages ranging from 9 to 65%, according to the experimental model tested[9,10,11]
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