OBJECTIVETo study the influence of estradiol on histomorphology of skin flaps with ischemia reperfusion injury.

METHODS48 adult male Wistar rats aged 12-14 weeks old, were randomly divided into control group (group I), ischemia-reperfusion group (group II), saline group (group III), estradiol group (group IV). Superficial epigastric artery axial flap, 3 cm x 6 cm in size, was made in the left lower quadrant abdominal of each rat. Flap model with ischemia-reperfusion injury was established by using the nondestructive micro vascular clamp to clamp the superficial epigastric artery. The general condition of the flap was observed after operation. At 7 days after operation, the survival rate of the flap was detected, the flaps were harvested to receive histology and ultrastructural observation. The neutrophils level of the superficial epigastric vein were tested.

RESULTS7 days after operation, the survival rate of the flap in group IV was significantly higher than that in group II, III (P < 0.05). The neutrophils level in group IV was lower than that in group II, III (P < 0.05). The histological observation showed that the degree of tissue swelling and inflammatory exudation in group IV was more slight than that in group II, III. Presence of high neutrophils density were observed in group II, III, while slight inflammation and necrosis were observed in group IV. In group I, collagen fibers in flap are regularly arranged with no significant necrosis. Oganelles structure disappeared and apoptotic bodies were shown in group II and group III, even the lysosome could be seen in the cell. Collagen fibers in flap are regularly arranged with slight swelling and no obvious ultrastructural necrocytosis was seen in the cell of group IV.

CONCLUSIONThe estradiol can significantly increase flap survival rate by inhibiting neutrophils infiltration and improving the pathological changes of organization structure in flap.