Ellagic acid attenuates hypoxic-ischemic brain injury by alleviating autophagy / 中国病理生理杂志

ABSTRACT

AIM:To investigate whether ellagic acid (EA) attenuates hypoxic-ischemic encephalopathy (HIE) by down-regulating autophagy.METHODS:In vivo, Sprague-Dawley rats (n=17) were randomly divided into 3groups5 rats for sham group, 6 rats for HIE group and 6 rats for HIE+EA pretreatment group.The rats in HIE+EA pretreatment group were treated with EA (10 mg/kg, 10 m L/kg, suspended in corn oil, ig).After 24 h of operation, the rats from each group were sacrificed and their brains were collected.TTC staining and HE staining were used to define the infarct areas and brain structure.The autophagy-related proteins beclin-1, P62, LC3-II/-I and Atg5 in the cortex in each group were compared by Western blot.In vitro, PC12 cells were divided into 3 groupscontrol group, Coand CoEA pretreatment group.Co800μmol/L was added to the PC12 cells to induce an anoxic environment.The PC12 cells were pretreated with EA at 8μmol/L and the cell viability was measured by CCK-8 assay.The production of reactive oxidative species (ROS) in the cells was detected by flow cytometry with DCFH-DA staining.MDC staining and TM-RE staining were applied to reflect the extent of autophagy and the state of apoptosis, respectively.The autophagy-related proteins in PC12 cells were also investigated.RESULTS:In HIE group, 7-day-old rats were given the operations and the their large infarct areas in the hemisphere were observed by TTC staining.HE staining displayed the injured hemispheres which contained few neurons, and exhibited edema status and serious structural damage.EA pretreatment decreased the infarct area and alleviated the damage to hemisphere with more visible neurons, compared with HIE group.Compared with sham group, the levels of autophagy-related proteins Atg5, beclin-1 and LC3-II/-I in the cortex were increased (P<0.01) , and P62 protein expression was decreased (P<0.01) in HIE group.Compared with HIE group, the protein expression of Atg5, beclin-1 and LC3-II/-I was decreased (P<0.01) and P62 protein expression was increased in HIE+EA pretreatment group (P<0.01).In vitro, compared with CoPC12 cells in CoEA pretreatment group showed a lower ROS level.Moreover, the cells in CoEA pretreatment group exhibited higher mitochondrial membrane potential than that in CoMDC staining in Coshowed high value of fluorescence and increased number of autophagosomes.EA pretreatment reduced the number of autophagosomes and the extent of autophagy to protect PC12cells.Furthermore, the protein levels of Atg5, beclin-1 and LC3-II/-I in Cowere higher (P<0.01) , and the protein expression of P62 was lower (P<0.01) than those in control group.In CoEA pretreatment group, the protein levels of Atg5, beclin-1 and LC3-II/-I were decreased (P<0.01) and the protein expression of P62 was increased as compared with Co (P<0.01).CONCLUSION:EA pretreatment attenuates autophagy to protect the neurons against HIE injury.