[Doxorubicin preconditioning instead of ischemic preconditioning in providing ischemic tolerance for rats abdomen island flaps].

Objective: To investigate the effects and mechanism of doxorubicin preconditioning in providing ischemic tolerance for rats abdomen island flaps.

Methods: Twenty-four healthy adult Sprague Dawley rats, 12 males and 12 females, were randomly divided into 3 groups (n = 8): control group (group A), ischemic preconditioning group (group B), and doxorubicin preconditioning group (group C). After the abdomen island flap (6 cm x 3 cm in size) based on the superficial inferior epigastric neurovascular bundle was prepared, group A had no further treatment; group B was given a 10-minute ischemia followed by a 10-minute reperfusion for 4 times; and group C was given pretreatment with doxorubicin (1 mg/kg) by injection of the inferior epigastric vein. After 24 hours, the inferior epigastric vessels were blocked by vascular clamp for 4 hours, followed by reperfusion 2 hours to prepare ischemia/reperfusion (I/R) injury model. The rat survival was observed after operation; at 0, 8, 12, 24, and 30 hours after I/R injury, the malonyldiadehyde (MDA) and superoxide dismutase (SOD) levels were measured. At 7 days after I/R injury, the survival rate of flap were calculated and the flaps were harvested for histological observation.

Results: During experiment, 5 rats died (1 rat in groups A and B respectively, 3 rats in group C) and were added. The survival rates of the flap in group A (10.10% +/- 0.43%) was lower than those in group B (91.63% +/- 1.76%) and in group C (92.75% +/- 1.48%) at 7 days after I/R injury, showing significant differences (P < 0.05), and there was no significant difference between groups B and C (t = 0.29, P = 0.77). Significant difference was found in MDA level and SOD level between group A and groups B, C after 8 hours (P < 0.05), and there was no significant difference between groups B and C (P > 0.05). Histological observation showed that inflammatory cells infiltration was more obvious and hyperplasia of fibers was weaker in group A than in groups B and C.

Conclusion: Doxorubicin preconditioning can provide ischemic tolerance for rats abdomen island flaps and protect flaps from the I/R injury. The possible mechanism may be related to that doxorubicin can induce endogenous protections.