Rev Bras Cir Plást. 2013;28(2):183-90 183 Does hyperbaric oxygenation have a protective effect on random skin flaps?Does hyperbaric oxygenation have a protective effect on random skin flaps? An immunohistochemical study of cellular apoptosis and vascular endothelial growth factor Existe efeito protetor da oxigenação hiperbárica em retalhos cutâneos randômicos? Um estudo imuno-histoquímico de apoptose celular e fator de crescimento vascular endotelial ABSTRACT Background: Hyperbaric oxygenation (HBO) therapy aims to increase oxygen tissue pres sure by at least 10 times and decrease the adverse effects of ischemia. The aim of this study was to investigate the effect of HBO on the immunohistochemical expressions of caspase 3 and vascular endothelial growth factor (VEGF) in random flaps in rats. Methods: Thir tytwo male Wistar rats were randomly divided into 4 groups: the sham group (GS), the Nacetylcysteine group (GNAC), the HBO group, and the HBO + Nacetylcysteine group. A rectangular skin flap (2 × 8 cm) was dissected from the dorsal muscle layer, and a cranial pedicle was preserved. A polyethylene film was placed on the muscle layer, and the flap was fixed in the original site. On the eighth day, biopsy samples (2 × 1 cm) of the entire thickness of the proximal, medial, and cranial areas as well as of the site outside the flap, which was used as a control, were collected. Results: VEGF expression in the skin layers and vessels was not significantly different between the groups. The number of apoptotic cells was significantly increased in the area of the flap in all groups. The highest increase was noted in the GS and GNAC groups. HBO significantly reduced the number of caspase 3positive cells in the skin layers and vessels of the 3 areas. Conclusions: HBO was asso ciated with decreased apoptosis. VEGF expression in the skin layers and vessels did not differ significantly. The results suggest that oxygen diffusion through the interstitial space was the determining factor for the positive effect of HBO on the decrease in apoptosis.

Objective:Our aim is to investigate the role of HBO (hyperbaric oxygen), NAC (N-acetylcysteine), and HBO plus NAC on the necrosis area of random rat's skin flaps of a modified McFarlane flap design.Materials and Methods:Thirty-two male Wistar rats were randomly divided into four groups: G-S (sham: n = 8), G-NAC (NAC: n = 8), G-HBO (HBO: n = 8), and G-HN (HBO plus NAC: n = 8). A rectangular skin flap (2 × 8 cm2) was dissected from the muscular dorsal layer, preserving the cranial pedicle. Polyethylene film was placed over the muscular layer and an interrupted 3.0 nylon suture was employed to fix the flap into the original place. On the eighth day, full-thickness biopsy samples (2 × 1 cm2) were collected from the proximal, middle, and cranial areas of the skin flap, and in a site away from the flap labelled as the control area.Results:The measurements of necrotic areas in the groups were 18.3% in G-S, 24.3% in G-NAC, 12.6% in G-HBO, and 14.9% in G-HN. Significant difference was observed between the groups G-HBO and G-HN as well as G-NAC.Conclusion:HBO is associated with reduced area of necrosis of skin flap. The G-NAC group was associated with poor results when examined in isolation. The association between HBO and NAC did not produce favourable results with respect to the use of HBO alone. These findings suggest that the diffusion of oxygen through the interstitial space was the determining factor of more favourable results of HBO.

Effects of hyperbaric oxygenation and N-acetylcysteine on the survival of random-pattern skin flaps in rats Effects of hyperbaric oxygenation and N-acetylcysteine on the survival of random-pattern skin flaps in rats Efeito da oxigenação hiperbárica e da N-acetilcisteína na viabilidade de retalhos cutâneos em ratos ABSTRACT Background: Advances in plastic surgery techniques have enabled reconstruction of extensive wound damage, especially through the use of random flaps. However, the limiting factor for the use of these flaps is the unpredictable blood supply, which may produce irreversible damage to the microcirculation and result in partial or complete flap necrosis, making the wound more susceptible to infection. Therefore, improvement of random flaps, especially in the distal extremity, has been an essential goal for the success of this technique. The objective of this study was to investigate the effects of hyperbaric oxygenation (HBO), N-acetylcysteine (NAC), and the combination of both (HBO + NAC) on the degree of necrosis in modified McFarlane random skin flaps on Wistar rats. Methods: A total of 32 male Wistar rats were randomly divided into a sham treatment group (SG, n = 8), N-acetylcysteine group (NACG, n = 8), hyperbaric oxygenation group (HBOG, n = 8), and hyperbaric oxygenation plus N-acetylcysteine group (HNG, n = 8). Modified McFarlane random flaps were created in the dorsal region of the rats. Results: The average area of the flaps exhibiting necrosis was 18.3%, 24.3%, 12.6%, and 14.9%, in the SG, NACG, HBOG, and HNG, respectively. The necrotic areas in the HBOG and HNG were significantly smaller than that in the NACG. Conclusions: HBO treatment was associated with a reduction in the area of necrosis in the skin flaps. NAC treatment alone gave poor results. The use of HBO and NAC in combination did not improve the outcome compared with the use of HBO alone. The findings suggest that oxygen diffusion through the interstitial space was the factor responsible for the favorable results of HBO.

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