Effect of Ghrelin on mitophagy in intestinal epithelial cells through the AMPK/FUNDC1 pathway

Abstract

Abstract Background The incidence and fatality rate of intestinal I/R injury are increasing year by year, which is a problem that the medical community has been concerned about and needs to be solved urgently. The aim of this study is to explore the effect of the gastrointestinal hormone Ghrelin on the AMPK/FUNDC1 mitophagy pathway under intestinal ischemia and reperfusion, and to clarify the mechanism of the protective effect of Ghrelin on intestinal epithelial cells. Method Adult male SD rats were randomized into four groups: sham surgery (Sham), I/R, I/R + Ghrelin, and I/R + Ghrelin + FUNDC1 antagonist group.A model of intestinal ischemia-reperfusion injury was established by clamped the superior mesenteric artery.Rat intestinal epithelium and lung tissues were taken to observe the histopathological morphology and autophagy activity.To measure the IL-6 test for inflammatory factor levels in intestinal epithelial cells, lung lobes, and peripheral blood by ELISA.The expression levels of autophagy proteins including AMPK, pAMPK, FUNDC1, and LC3 in all the rat intestinal epithelial tissues were determined by Western blot.Intracellular ROS levels were measured by a reactive oxygen species fluorescent probe. Using JC-1 probe to detect mitochondrial membrane potential levels.And the expression was determined by quantitative mtDNA by PCR. Result HE staining showed that there was no significant intestinal mucosal damage in Sham group,while intestinal mucosal damage was evident in I/R group.Similarly,the villus structure in the I/R + group was nearly normal but the structural in the I/R + Ghrelin + FUNDC1 antagonist group was like that in I/R group. Compared with the Sham group, IL-6, ROS, and mtDNA levels were significantly increased while the levels of mitochondrial membrane potential and AMPK, FUNDC1, and LC3 protein expression were decreased in group I/R rats (all P <0.05). Compared with the I/R group, the oxidative stress was reduced in the I/R + Ghrelin group, with improved mitochondrial energy metabolism and increased mitophagy protein expression (all P <0.05).However, the I/R+Ghrelin+FUNDC1 inhibitor group reversed the protective effect of the I/R+Ghrelin group, and the results of each test index were close to the I/R group (all P <0.05). Conclusion: Ghrelin can protect against intestinal ischemia and reperfusion injury and distant organs, which may be regulated by the mitophagy pathway of FUNDC1 by AMPK protein.