Curcumin attenuates rat lung ischemia/reperfusion injury by interfering with autophagy

AIM To investigate the role of curcumin （CUR） in lung ischemia/reperfusion （I/R） injury （LIRI） and its relationship with autophagy. METHODS 40 SD rats were randomly divided into sham operation （sham） group， I/R group， solvent （DMSO） group， CUR group and CUR+rapamycin （CUR-Rap） group. The rats were intraperitoneally injected with normal saline， DMSO， CUR or CUR+Rap before operation. After the rat LIRI model was established， the lung tissues were taken to measure W/D， TLW， IAR， and the contents of SOD and MDA were also measured to indicate the oxidative stress level. Light and electron microscopes were used to observed the morphology and ultrastrucure of lung tissues. The expression levels of autophagy-related proteins were determined by Western blot to evaluate autophagy levels. RESULTS Compared with sham group， wet weight/dry weight （W/D）， total lung water （TLW）， injured alveoli rate（IAR） and malondialdehyde （MDA） content in all other groups were increased， superoxide dismutase （SOD） activity was decreased， the levels of autophagy were increased （P<0.05）， and lung tissue injury and cell ultrastructural damage were aggravated in CUR group. Compared with DMSO group， W/D， TLW and IAR and MDA content were decreased， SOD activity was decreased， autophagy levels were also decreased （P<0.05）， and lung tissue and cell ultrastructural damage were attenuated. Compared with CUR group， W/D， TLW， IAR and MDA content were increased， SOD activity declined， the autophagy levels were increased （P<0.05）， and damage of lung tissues and cells were more serious in CUR-Rap group. CONCLUSION Curcumin attenuates the lung I/R injury in rats， and its mechanism may be related to the reduction of oxidative stress and the inhibition of autophagy.