| objectiveTo investigate the protective effect and the effective dose of PACAP on HIBD,and explore an efficacious treatment for clinical therapy of neonatal HIE.Methods1.Establishment of HIBD model:Sixty 7-day-old Sprague-Dawley rats were randomly divided into 3 groups:sham operated group,hypoxic-ischemic(HI) group,and PACAP treatment group which was further divided into 3 subgroups: PACAP-H(10-8mol),PACAP -M(10-9mol),and PACAP-L(10-12mol).Neonatal rats were subjuected to a middle anterior neck incision.The left common carotid artery was isolated and ligated,then the rats were exposed to hypoxic environment (8%02,92%N2) for 2 hours.The sham operation group were only separated the left common carotid artery.Normal saline(NS)was intracerebroventricularly injected to HI group 15min before HI,and was replaced by PACAP in PACAP treatment group.The rats were sacrificed 24h after HI.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:The appearance of the brain was Observed.4.Expression of SOD,MDA,caspase-3mRNA and XIAPmRNA:The method of Xanthine Oxidase,Thibabituric Acid and Real time fluorescent quantitative PCR were used to detect the expression of SOD,MDA,caspase-3mRNA and XIAPmRNA of injured brian tissue 24h after HIBD respectively.Results1.Changes of behavior of the rats:Before the experiment all rats were healthy. 1h after HI,the rats in sham group were still healthy,while out of 48 rats which bared HI injury 12 rats could not turn themselves over,18 rats became levorotary when their tails were gripped and 18 rats exhibited both behavior Problems.2.General examination of the brain:The ligated brain hemisphere of HI group Showed obvious pallor and edema at 24h.The PACAP group showed no significant change or little edema.The two brain hemispheres of sham group showed no pathological change.3.Expression of SOD and MDA:Compared to the sham group,the injured brain tissue of HI group showed increased expression of MDA(p＜0.01) and decreased expression of SOD significantly(p＜0.01).Compared to the HI group,the injured brain tissue of all PACAP gruops showed decreased expression of MDA(all p＜0.01) and increased expression of SOD significantly(all p＜0.01).4.Expression of caspase-3mRNA and XIAPmRNA:Compared to the sham group,the injured brain tissue of HI group showed increased expression of both caspase-3 mRNA and XIAP mRNA significantly(all p＜0.01).Compared to the HI group,the injured brain tissue of all PACAP gruops showed decreased expression of caspase-3mRNA(all p＜0.01) and increased expression of XIAPmRNA significantly (all p＜0.01).Conclusions1.The HIBD model was successfully established.2.After HIBD,the expression of MDA increased and the total SOD activity decreased,which indicated the Oxygen free radical injury after HI.The expression of both caspase-3mRNA and XIAPmRNA increased,which suggested the apoptosis and self-regulation of anti-apoptosis after HI.3.PACAP might protect the brain tissue after HI at three doses(10-8mol,10(-9)mol and 10(-12)mol) through protecting SOD inhibiting MDA,up-regulating XIAP and inhibiting caspase-3 which can decrease the apoptosis of neuron.Our conclusion may be useful for the clinical treatment of HIE. |
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