The Expression Of NPTX1in Neonatal Rats With Hypoxic Ischemic Brain Damage And Neuroprotection Of Puerarin

Objective To investigate the effects of puerarin on the expression of NPTX1in neonatal rats with HIBD and explore its possible protective mechanism of brain.at the same time,detect the changes of blood glucose of neonatal rats with HIBD after applying with Puerarin in order to provide some references on studing and researching in the relative investigations.Methods1. Establish HIBD model according to Rice:Neonatal Seven-day-old Sprague-Dawley (SD) rats were subjected to a middle anterior incision.The left common carotid artery was isolated and ligated, pups were then exposed to hypoxic environment, with constant flow0.5L/min of humidified8%O2balanced with92%N2for2hour, and the behavior of the rats was observed during hypoxia.2. Evaluate neurofunction of the rats:righting reflex and levorotary ability when their tails were gripped were observed before the experiment,1h after HI and24h、48h after the first i.p. therapy.3. General examination of the brain:observe of the brain after HI.4. Assay the expression of NPTX1using real-time RT PCR.48Seven-day-old Sprague-Dawley (SD) rats were divided randomly into sham control. HIBD and puerarin-treated group. Puerarin100mg/kg was intraperitoneally injected to puerarin group1h、24h and48h after HI respectively,equal volum NS was injected to the other groups. The rats were sacrificed24h and48h after operation. mRNA expression of NPTX1were evaluated by real time RT-PCR analysis.5. Detect the changes of blood glucose of neonatal rats before experiment,1h after HI,4h after the first treatment and4h after the second treatment.Results1. Neurofunction evaluation of the rats:before the experiment all rats were healthy.the rats in sham group were healthy at the other evaluation point,while the righting reflexs of12rats were positive,5rats became levorotary when their tails were gripped and15rats exhibited both behavior problems in the32rats which bared HI injury. After the first treatment, righting reflex of10out of16in puerarin group and8out of16in HIBD group recovered. Applying puerarin for a short time after HIBD could shorten the time of righting reflex.2. General examination of the brain:The ligated brain hemisphere of HIBD group showed pallor and edema at24h and necrosis lesion at48h after HI. Edema was not serious and disappeared quickly in the Puerarin-treated group.The two brain hemispheres of sham group were symmetric and showed no significant change.3. The expression of NPTX1were evaluated by real time RT-PCR analysis Compared with sham control, the expression of NPTX1in ischemic brain tissue after HIBD was markedly enhanced. Median and25th-75th percentile:24h247.03(138.28-271.55)vs4.60(3.16-14.07);48h87.03(79.45-94.83)vsl.49(1.00-1.89). Puerarin significantly reduced the expression of NPTX1in ischemic brain tissue after HIBD. Median and25th-75th percentile:24h45.70(44.41-56.28);48h24.08(23.09-25.50)(P＜0.05).4. There were no statistic differences in blood glucose among groups before experiment, the blood glucose of all rats were in normal range.The differences of blood glucose among groups1h after HI had no statistic significance, but there were6hyperglycemia and1hypoglycemia in puerarin group and HIBD group respectively,blood glucose of rats in sham group were all normal. Statistic differences were existed among groups4h after the first treatment.7out of8in HIBD group and6out of8in puerarin group were hyperglycemia. There were no statistic differences among groups4h after the second treatment.The blood glucose reference of neonatal rats was:5mml/L～7mmol/L.Conclusions1. The HIBD model was established successfully.2. NPTX1played an important role in HIBD, Puerarin attenuate HIBD by down-regulation the expression of NPTX1in ischemic brain tissue.3. Applying puerarin after HIBD could shorten-the-time-of righting reflex4. Applying puerarin for a short time after HIBD could not affect the changes of blood glucose further.