Effects of exogenous recombinant human erythropoietin on neuronal apoptosis and 5-lipoxygenase in neonatal rats with hyperoxia brain injury / 中华实用儿科临床杂志

ABSTRACT

Objective To explore the effect of exogenous recombinant human erythropoietin (rhEPO) on neuronal apoptosis in neonatal rats after hyperoxia brain injury.Methods Thirty neonatal Wistar rats were randomly divided into 3 groups by random number table method:rhEPO treatment + 800 mL/L hyperoxia group (group A),9 g/L saline +800 mL/L hyperoxia group (group B),9 g/L saline + air group (group C).Group A was given subcutaneous injection of rhEPO 1 000 IU/kg for 5 days.Group B and group C received the same dose of 9 g/L saline.Group A and group B were continuously exposed to atmospheric pressure hyperoxia model cabin to maintain the oxygen concentration in the container (800 ± 30) mL/L for 5 days.During the course of the experiment,the general situation and weight changes in rats were observed.After 5 d,all rats were sacrificed and brain tissues were taken.Neuronal apoptosis in hippocampal structural region of the newborn rats was observed by terminal deoxynucleotidyl transferase dUTP nick and labeling(TUNEL) staining.Immunohistochemical method was used to detect the expression of 5-lipoxygenase in hippocampal structural region of newborn rats.Results The weight gain and brain weight of group B were lower than those of group C,the weight gain and brain weight of group A were higher than those of group B,and the differences were statistically significant(F =11.179,8.140,all P ＜ 0.05).In group A and group B were found that the neuronal nucleus of the hippocampal neurons was partially contracted,deeply dyed,and the neuronal arrangement was loose,even with local neuron deletions and focal necrosis,but in group A neuron density was higher with less necrosis than that in group B.The neuronal cells in hippocampal structural region were neat and intact in group C.The number of TUNEL positive cells in hippocampal structural region of group B[(6.20 ± 1.93) number/high power field] was significantly higher than that in group C [(1.80 ± 0.79) number/high power field],the number of TUNEL positive cells in hippocampal structural region of group A [(4.20 ± 1.32) number/high power field] was significantly lower than that in group B,and the difference was statistically significant (F =23.912,P ＜ 0.05).The number of 5-lipoxygenase positive cells in group B [(6.90 ± 1.29) number/high power field] was significantly higher than that in group C [(1.00 ± 0.67) number/high power field],the number of 5-lipoxygenase positive cells in group A [(5.60 ± 0.97)number/high power field] was significantly lower than that in group B,and the difference was statistically significant (F =95.044,P ＜ 0.05).Conclusion rhEPO has a protective effect on neonatal rats with hyperoxia brain injury,and alleviates brain cell apoptosis caused by hyperoxia brain injury,which may interfere with the 5-lipoxygenase pathway.