The Protective Effect Of Allopurinol In Hypoxic-Ischemic Brain Injury Of The Neonatal Rats

ObjectiveIn this research a HIBD model was established,and ALLO was intraperitoneally injected on different days.Then we study the effects of ALLO on the expression of SOD,MDA,·OH and the transcription of caspase-3 gene,in order to investigate the protective effect of ALLO in HIBD.Our research may provide an efficacious treatment for clinical therapy of neonatal HIBD.Methods1.Establishing of HIBD model:Neonatal 7-day-old Wistar rats were subjuected to a middle anterior neck incision.The left common carotid artery was isolated and ligated,then the pups were exposed to hypoxic environment(8%O₂,92%N₂)for 2 hours,and the behavior of the rats was observed during hypoxic.2.Observing behavior of rats:The turnover ability and levorotary ability when their tails were gripped were observed before the experiment and 1 h after HI.3.General examination of the brain:Observed general form of the brain.4.Expression of SOD,MDA,·OH and caspase-3 gene:56 seven-day-old rats were randomly assigned to sham operation group(sham),normal saline- treated control group(NS)and ALLO-treated group(ALLO).The left common carotid artery of the sham operation group was isolated but not ligated,and the rats were sacrificed 24h after operation.NS was intraperitoneally injected to NS control group 1h and 24h after HI respectively,and was replaced by ALLO in ALLO group.The rats were sacrificed 0.hh,24h and 72h after the last injection.Useing the method of Xanthine Oxidase,Thibabituric Acid,Fetion Reaction and RT-PCR,the expression of SOD,MDA,·OH and caspase-3 gene were measured.Results1.Changes of behavior of the rats:Before the experiment all rats were healthy.1 hour after HI,the rats in sham group were still healthy,while 26 rats couldn't turn themselves over and 38 rats became levorotary when their tails were gripped in the 48 rats which bared HI injury,There were 16 rats exhibited both behavior problems.2.General examination of the brain:The ligated brain hemisphere of NS control group showed obvious pallor and edema at 24h,and showed liquefactive necrosis lesion at 72h.The ALLO-treated group showed no significant change or little edema. The two brain hemispheres of sham group showed no pathological change.3.Expression of SOD,MDA,·OH:Compares with sham group,the expression of MDA and·OH increased in NS group at 24h,72h after HIBD(P＜0.05),and was lower at the same time in ALLO-treated group(P＜0.05).Compares with sham group, the total activity of SOD decreased in NS group at 24h,72h after HIBD(P＜0.05), and increased at the same time in ALLO-treated group(P＜0.05)4.Transcription of caspase-3 gene:Compares with sham group,the transcription of caspase-3 gene increased in NS group at 24h,72h after HIBD,and was lower at the same time in ALLO-treated group(P＜0.05).There was significant difference between NS group and the sham group,and also between saline-treated group and ALLO-treated group(P＜0.05).Conclusions1.The HIBD model was successfully established.2.After HIBD,the expression of MDA,·OH increased and the total SOD activity decreased,which showed the oxygen free radical injury after HI.The transcription of caspase-3 gene increased,which showed the apoptosis after HI.3.ALLO might protect the brain tissue after HI through inhibiting the expression of MDA,·OH,protecting SOD and down-regulating the transcription of caspase-3 gene which can decrease the apoptosis of neuron.Our conclusion may be useful for the clinical treatment of HIBD.