RESUMO
BACKGROUND: Early application of hyperbaric oxygen adjuvant therapy can relieve blisters, swelling and other symptoms, and thus improves the survival rate of skin flaps. Edaravone can effectively eliminate free radicals in the injured area of skin flaps. OBJECTIVE: To investigate the effect and mechanism of hyperbaric oxygen combined with edaravone on the survival rate of avulsed flap in rabbits. METHODS: Fifty-four healthy New Zealand white rabbits were provided by Laboratory Animal Center of Medical Collage of Soochow University. A 1.5 cm x 8 cm pedicled rectangle flap of the rabbit central artery was made on the middle of the rabbit left ear back, and created crush injury using special device. The 48 model rabbits were randomly divided into four groups (n=12/group), and received no intervention (control group), hyperbaric oxygen therapy, 3 mg/kg·d edaravone injection via tail vein, or hyperbaric oxygen therapy combined with edaravone (combination group), for 3 continuous days. The microcirculation of skin flap was observed at 3 days after treatment. The flap survival area was measured at 7 days after treatment. The survived flap was removed for hematoxylin-eosin staining. The expression levels of intercellular adhesion molecule-1 and vascular cell adhesion molecule 1 in flap tissue were detected by RT-PCR and western blot assay. RESULTS AND CONCLUSION: (1) Laser doppler and infrared thermal imaging system showed that the blood perfusion reached the distal segment of skin flap in the combination group, reached the middle segment of skin flap in the hyperbaric oxygen and edaravone groups, and reached the proximal segment of skin flap in the control group. (2) The survival rate of flap in the combination group was significantly higher than that in the other three groups (P ＜ 0.05). The survival rate in the edaravone and hyperbaric oxygen groups was significnatly higher than that in the control group (P ＜ 0.05). (3) The degree of inflammatory infiltration in the combination group was significantly low, and the degree of inflammatory infiltration in the control group was significantly higher than that in the hyperbaric oxygen and edaravone groups. (4) The mRNA and protein expression levels of intercellular adhesion molecule-1 and vascular cell adhesion molecule 1 detected by RT-PCR and western blot assay were lowest in the combination group (P ＜ 0.05), and the levels in the hyperbaric oxygen and edaravone groups were significantly lower than those in the control group (P ＜ 0.05). (5) To conclude, hyperbaric oxygen combined with edaravone can effectively promote the survival of rabbit ear avulsed skin flap, which is related to the decreased expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule 1.