Doxorubicin Preconditioning Instead Of Ischemic Preconditioning In Providing Ischemic Tolerance For Rats Abdomen Island Flaps

In plastic and reconstructive surgery using skin flap to repairing wounds, there is often happening severely Ischemia/Reperfusion(I/R). It cuts down skin flap survival rate. Its etiopathogenesis is complicating and now is not contently prevented and cured. For the past few years documents report:the cardiac muscle can tolerance ischemia for more longer time after it is repeatedly experienced the ischemia of brief time;this phenomenon is called Proconditioning (PC). The protection after PC shows tow discontinuous phases. The instant protection disappears after 2～3 hours , reappears after 24 hours and keeps for several days.The latter is called Delayed Protection(DP). This mechanism is still not distinctly. The possible mechanism for improvement may lies in that PC can induce endogenouse protections such as heat-shock protein(HSP) and hyperoxide dismutase.Doxorubicin(Dox) is a kind of glucoside antibiotics extracted from variant streptomycete and widespreadly displayed in tumor chemo. Dox can interfere the anabolic effect of the cell's DNA and RNA . It can be decomposed by enzyme , become semiquinone free ridicule, and generate oxyger free ridicule after reacting with oxyger. These injury factors can induce a endogenouse protection machine and make cell producting irritable protective protein. Therefore some scholars succeed in Doxorubicin preconditioning instead of ischemic preconditioning in providing ischemic tolerance for rat Live.Object: To investigate the effects of low dose Dox on the surivival of ischemia-reperfusion island skin flaps in rat,in addition determine whether doxorubicin preconditioning (DP) can be used to replace PC in inclucing the delaying protective effect.Method: Twenty-four healthy SD rats, male 12 and femal 12, were randomly distributed to three groups :A operation contral group, B ischemia- preconditioning (IPC) experimental group ,C doxorubicin preconditioning (DP) experimental group. The abdominal 3×6cm island flap based on the inferior epigastric vessela was used as the ischemic reperfusion model. A group's island flaps were sutured .A 10-min ischemia followed by a 10-min reperfusion of the island skin flaps for four times was inflicted in rats in B group while pretreatment with doxorubicin (1mg/kg, iv) by injected into rats abdominal cavity was performed in C group. The there groups were anesthetized again after 24 hours of the operation and were blocked by vascular clamp for 4 hours and reperfusion 2 hours. After the preconditioning 0 hour,8 hours,12 hours, 24 hours, 30 hours some tissues were taken to detect the MDA, SOD. The rats were killed 7th day after the I/R injury. The comparison of two groups included the gross observation , tissue pathology and the survival ratio of the flap.Result: The mean survival rate of the flap in A group is 10.10±0.43 % at the 7th day and it is about 100% in the B,C group, which show significant difference in statistics(p<0.05).Statistically significant difference is also obtained in MDA level and SOD level between the A group and the B,C group, whereas no significant differences were found between the B group and the C group (P>0. 05).Conclusion: Doxorubicin preconditioning can be instead of ischemic preconditioning in providing ischemic tolerance for rats abdomen island flaps and protect skin flaps from the Ischemia/Reperfusion(I/R) injury.The possible mechanism for improvement may lies in that DOX can induce endogenouse protections.