| Objective:To explore the influence of erythropoietin on the expression of CCAAT enhancer binding protein homologous protein(C/EBP homologous protein,CHOP)and glucose regulation protein 78(GRP78)and its mechanism.Methods:One hundred and twenty neonatal Wistar mouse were randomly divided into 3 groups:air control group(n=40,FiO2=21%),high oxygen group(n=40,FiO2>85%),high oxygen+EPO group(n=40,FiO2>85%).Air control group is exposed to indoor air,the newborn mouse of high oxygen group and high oxygen+EPO group were exposed to oxygen concentration in the glass box above 85%.In the first day of the experiment,EPO800U/kg was injected into the abdominal cavity of high oxygen+EPO group,high oxygen group intraperitoneal injection of same amount of 0.9%NaCl.Experiment 1,3,7 and 14 days to determine the weight change of the neonatal mouse,to measure(W/D)in brain tissue,routine HE staining observed the morphological changes of brain tissues,the expressions of CHOP,GRP78,Bcl-2 and Bax protein expression were detected by western blot.Result:1.The weight of 1 st,3rd,7th and 14th day of neonatal mouse in the hyperoxia group was significantly lower than that in the control group(P<0.05).The high oxygen+EPO group of neonatal mouse showed a significant increase in weight of the higher oxygen group at each time point(P<0.05).2.The wet/dry weight(W/D)ratio of the brain tissues in the hyperoxia group were higher than that in the control group in the 1st,3rd,7th and 14th day(P<0.05),the longer the exposure time,the greater the difference.High oxygen+ EPO group of neonatal mouse showed a decrease in the amount of water in the brain at each time point(P<0.05).3.High oxygen and air group compared brain structure exists different degree of swelling,necrosis and inflammation,with high oxygen exposure time to extend the pathological changes in obvious increase;degree of pathological changes and high oxygen+EPO group were lighter than the same period of high oxygen groups.4.The expression of CHOP and GRP78 protein in the 1 st,3rd,7th and 14th day of the high-oxygen group was significantly higher than that in the control group,Bax protein expression was slightly elevated,and the expression of Bcl-2 decreased significantly(all P<0.05).The expression of CHOP,GRP78,and Bax protein in the higher oxygen+EPO group was significantly reduced were decreased with the expression of the higher oxygen group at each time point,the content of Bcl-2 protein expression was up-regulated,and the difference was obvious(all P<0.05).Conclusion:1.EPO can alleviate the inflammatory response such as cerebral edema caused by hyperoxia and neuroprotective effect on hypertoxic brain injury,and its mechanism is related to the reduction of CHOP and GRP78 protein expression that are closely related to the down-regulation of endoplasmic reticulum stress.2.EPO protection mechanism may also be related to the inhibition of anti-apoptotic protein Bcl-2 expression. |
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