Objective To explore the relevance between nitrate transporters (Sialin) and ischemia-reperfusion injury (IRI) in free flaps.Methods Twenty rats were randomly divided into control group and experimental group,10 in each group.After preparatiing 4 cm×8 cm free tissue flap on left lower abdominal,the rats in experimental group were experienced ischemia in 6 hours,then reperfusion.The rats in control group were without ischemia treatment,and tissue flaps were sutured in situ.After postoperative observation for 7 days,the furthest edge of survival flaps were sampled.The expression of Sialin was detected by the Real-time PCR and Western blot.The change of nitrate content was analysed by chemiluminescence.Results Both of results of Real-time quantitative PCR and Western blot,it was found that expression levels of Sialin in the experimental group were significantly lower than the control group(0.945±0.0530)(P＜0.05).Applying Real-time quantitative PCR relative quantitative analysis,it was found that the experimental group Sialin mRNA expression level was 0.284±0.0486,significantly lower than that of control group (0.945±0.0530)(P＜0.05).Using Western blot technical analysis,experimental Sialin protein expression level was(0.1413±0.0446),significantly lower than the control group (0.3519±0.0368) (P＜0.05).The concentration of nitrate of test results found that the expression of nitrate transporters (Sialin) linearly related with the concentration of nitrate in free flaps,which means tbe Sialin expression level decreased,the nitrate content decreased(P＜0.05,R=0.81).Conclusion The concentration of nitrate was linearly related to the level of Sialin expression:when Sialin expression levels dropped,the concentration of nitrate decreased.Nitrate transporters(Sialin) may be correlated with IRI in free flaps.