关键词: 肺, 缺血/再灌注, 肝损伤, 细胞自噬, 大鼠

Abstract: Objective: To investigate the liver injury induced by lung ischemia / reperfusion(LI/R) and the role of autophagy in its prevention and treatment. Methods: The lung ischemia/reperfusion injury(LI/RI) model was prepared by anesthetizing the rats, cutting the trachea for mechanical ventilation, and using an arterial clamp to close the pulmonary hilum to simulate the ischemic process, and releasing the arterial clamp after 30 min to resume perfusion for 3 h. SD rats(n=24)were randomly divided into sham operation(sham)group,ischemia/reperfusion(I/R)group,solvent(DMSO)group and autophagy inhibitor (3-MA) group, 6 rats in each group. The rats were intraperitoneally injected with medicine before operation. After the rat LI/RI model was established,the rats were killed, and the lung wet/dry weight ratio was used to evaluate the success of modeling, the venous blood was collected to measure the contents of ALT and AST, and the liver tissues were collected. Light and electron microscopes were used to observed the liver tissues and cell shapes. The protein and mRNA expression levels of autophagy related proteins were determined by Western blot and RT-qPCR to suggest autophagy levels. Results: Compared with sham group, the lung wet/dry weight ratios in other groups were elevated, and the liver tissues of other groups were damaged significantly. Serum levels of AST and ALT were increased significantly and liver tissue damage was obvious, especially in I/R group. The light microscopy showed that the arrangement of hepatic cords was disordered or broken, hepatic sinuses were dilated, and edema of liver cells were observed; transmission electron microscopy showed varying degrees of mitochondria swelling up in liver cells in the other groups. At the same time, the expressions of AMPK, Beclin 1 and LC3 mRNA were increased, but the expressions of mTOR and p62 mRNA were decreased; the protein expressions of p-AMPK, Beclin 1, LC3-B were increased significantly, but those of p-mTOR and p62 were decreased (all P＜0.05). Compared with DMSO group, the injury of liver tissue in 3-MA group was alleviated, the damage degree of mitochondrial ultrastructure was lower, the levels of AST and ALT were decreased, the transcription and protein expression levels of autophagy related protein in liver tissue were decreased (P＜0.05). However, the injury degree of IR and DMSO groups were similar, and there was no significant differences in each index (P＞0.05). Conclusion: Lung ischemia/reperfusion can cause liver injury in rats. Autophagy can mediate liver injury induced by lung ischemia / reperfusion in rats and inhibiting autophagy can effectively reduce liver injury induced by LI/R in rats.

Key words: lung, ischemia/reperfusion, liver injury, autophagy, rats