Effects Of Deferoxamine On Expression Of BrdU And GFAP In Brain Of Neonatal Rat With Hypoxic-ischemic Brain Damage

Objective In this study we investigate the effects of deferoxamine (DFO) on the expression of 5-bromo-deoxyuridine (BrdU) and glial fibrillary acidic protein (GFAP) in subgranular zone (SGZ) and CA1 region after hypoxic-ischemic brain damage (HIBD) in neonatal rats, to explore the neuroprotective effects of deferoxamine according to the regeneration of nerve cells and the improvement of learning and memory capability by using the Morris water maze, in order to obtain the experimental evidences of prevention and cure for hypoxic-ischemic encephalopathy of neonates. Methods Thirty two HIBD models of neonatal Wistar rats were made by shearing right arteria carotis communis and then breathing 8%O2+92%N2 for one hour. The models were divided into two groups randomly:the trial group of DFO and the control group of normal sodium. The other sixteen neonatal Wistar rats were taken into the sham operation group. Expressions of BrdU and GFAP on dentate gyrus (SGZ) and the CA1 region were examined with immunofluorescence technique staining and image quantitative analysis at the 4th days after the operation. Pathological change of brain was investigated with microscope. Each group's spatial cognitive capability was evaluated by using the Morris water maze also. Results 1.Pathological change of brain:There were no anomaly in the sham operation group found. The hippocampus pyramidal cell layers were decreased and the cells arranged in disorder in the control group of HIBD, lots of neurocytes were karyopycnosis and nuclear fragmentation in hippocampal CA1 region of rats. Compared with the control group of HIBD, the damages in DFO treated group are mild.2. Expression of BrdU: BrdU-positive cells were mainly distributed SGZ area at the 4th days after the operation. The expression of BrdU in SGZ region of rats was significantly difference in three groups (P＜0.05). The number of BrdU-positive cells of control group of HIBD was obviously more than the sham operation group (P＜0.05), and that of DFO treated groups increased compared with the control group of HIBD(P＜0.05), and that of DFO treated groups significantly increased compared with sham operation group (P＜0.05).3. Expression of GFAP:GFAP-positive cells were mainly distributed in the hippocampal CA1 and CA3 regions at the 4th day after the operation, the expression of GFAP in CA1 region and CA3 regions of rats was significantly difference in three groups (P＜0.05). The number of GFAP-positive cells in the control group of HIBD was obviously more than the sham operation group (P＜0.05), and that of DFO treated groups was significantly increase compared with the control group of HIBD(P＜0.05), the number of GFAP-positive of DFO treated groups significantly increase compared with sham operation group (P＜0.05).4. Determination of Morris water maze:(1) Learning ability:The latency to escape was significantly difference in three groups (P＜0.05), the sham group is the shorter compared with the DFO treated groups, the control group of HIBD is the longest. (2) Memory capacity:The memory ability was significantly different in three groups (P＜0.05), the frequency of passing the platform of the control group of HIBD was the minimum. But there was no significant difference between the sham operation group and the DFO treated group(P＞0.05). Conclusions 1. Exogenous DFO could relieve the pathological damage of brain due to cerebral anoxia and cerebral ischemia in neonatal rats.2. The expression of GFAP and BrdU increased in CA1 region of neonatal rats with HIBD, show that the existence of the regeneration of neurocytes in neonatal rat brain after HIBD, it may be involved in the regeneration of neurocytes and activation of neural stem cells after HIBD.3. DFO early intervention can promote regeneration and restoration of damaged nerve cells of neonatal Wistar rats with HIBD.4. DFO early intervention can improve the ability of learning and memory in the neonatal Wistar rats with HIBD.