Effects of various protocols of ischemic preconditioning on rat tram flaps

We used rat transverse rectus abdominis musculocutaneous (TRAM) flaps to investigate whether the ischemic cycle duration and number of cycles influenced the effectiveness of ischemic preconditioning (IPC). First, the animals were divided into one control group and four treatment groups. Controls received no preconditioning; flaps with IPC were treated by two cycles of pedicel clamping and reperfusion for either 5 or 10 min. Then the best of IPC protocols in first part was selected, and flaps were subjected to one or three cycles of IPC before 4 h of normothermic ischemia. The preconditioned flap survival area had improved 2.5-3 times over that of the control area by postoperative day 7. Serum creatine phosphokinase (CPK), water content, and malondialdehyde (MDA) in muscle were significantly decreased in the preconditioned groups after 4 h of reperfusion. Especially, 2 and 3 cycles of the 10/5-min combination were more effective than other protocols of IPC.