The Effect And Mechanism Of Nerve Growth Factor Intervention On Apoptotic Neuron In Hippocampus Of Immature SD Rats After Status Epilepticus

BackgroundStatus epilepticus is a very common emergency in clinical departments, especially in pediatric neurological department. International League Against Epilepsy(ILAE) define that a seizure lasting 30 minutes or more, or repeated episodes of lasted 30 minutes and interictal consciousness can not return to the baseline state attack. Revelant animal experiments confirmed that if the SE last 30 min, neurons begin to die and the apoptosis is the main form and plays an important role in cerebral neuronal death.In 1972, Kerr first proposed the concept of the death of cells, according to the different characteristics of the ultrastructure of the cells, and divided it for necrosis and apoptosis.Early studies are mostly concentrated in neurons of normal developmental processes. Numbers studies showed the number of survived cell after traumatic brain injury has a directly relation to the neurons apoptosis and palyed very important role in the prognosis after brain injury. The apoptosis of nerve cells depends on the anti apoptotic factors inhibitory and apoptosis inducing factors.Related stadies and animal researches proved that there are at least three signal transduction pathway involved in the apoptosis.The activation and inhibition of Cysteinyl aspartate enzyme family of caspase are involved in the pathway of apoptosis;the protease system is located in the intersection of many apoptotic pathways,resulting in the disintegration of cell apoptosis.Caspase9 is the most important apoptosis initiation factor,at the top of Caspase "waterfall". Related research found that Human inhibitor of apoptosis proteins(IAPs) were unique among the intracellular anti-apoptotic protein family. X-IAP was the only anti-apoptotic protein which combined with start-apoptotic factors Caspase9 and effecter Caspase3. Evidences showed that activation of Caspase-9 and Caspase-3 and the release of cytochrome C were involved in ischemia-induced neuronal apoptosis. Lots stadies proved that: NGF played a positive role in promoting the recovery of neurological function after injury. NGF on cerebral ischemic neuronal degeneration, necrosis, protect and repair. NGF normal neuronal apoptosis inhibition, anti-injury can enhance the ability of nerve cells.The current international and domestic have not substantive breakthrough in the specificity targets of apoptosis, to study the upper regulator caspase9 and may found specificity targets anti apoptotic drugs has excellent prospects. ObjectiveBuild the lithium-pilocarpine SE model.To explore the effect and mechanism of NGF intervention by tested the expression of Caspase3 ? Caspase9 and XIAP in the hippocampus of immature SD rats after status epilepticus, and then to find the target upstream and provide a theoretical basis for clinical treatment. Methods1.SD male rat pups were randomly divided into nine groups,(1)NG;(2)4h group after SE,(3)8h group after SE,(4)24h group after SE,(5)72h group after SE;The NGF intervention group:(6)4h group after NGF,(7)8h group after NGF,(8)24h group after NGF,(9)72h group after NGF?2.Use TUNEL method to examine the apoptosis cells and use the immunohistochemistry method to detect the expression of Caspase3?Caspase9?XIAP. Results1.Few TUNEL-positive cells were found in normal group; In the SE group, TUNEL positive cells are significantly increased after 8 hours and reached the peak at 72 hours. In the NGF group,the trend of the expression of TUNEL-positive cells was similar to the SE group, but the number of positive cells was less than the SE group.2.In the normal group, few positive cells can be found in the hippocampal; compared with the normal group, the positive cells of the SE group were significantly increased, and reached the peak at 24 h, slightly reduced at 72 h. In the NGF group, the trend of positive cells of the Caspase3 were the same as the SE group, but significantly reduced compared with SE group at the corresponding time points. The trend of expression of positive cells of Caspase9 were similar with the Caspase3 in SE group and NGF group, but the protein of Caspase9 was less than the SE group at the 24 h and 72 h.3.The positive cells of the XIAP in the hippocampus of the nucleus or cytoplasm stained yellow. Few positive cells were found in the normal group; In the control group, the positive cells increased significantly and the degree of dyed cells were heavier than the normal group, the expression began to increase at 4h, and reach the peak at 8h; In the NGF group, the expression of XIAP was similar to the SE group, but the expression of XIAP were significantly more than the SE group. Conclusions1.The status epilepticus can lead to apoptosis of neuronal cells in the acute period of SE, with the time delay, the more apoptotic cells.2.The apoptosis occued may be because the activation of caspase3 and caspase9, which can lead to activation of cell apoptosis; when apoptosis occurs, XIAP expression due to stress and for inhibition of apoptosis proteins.3.NGF may play a role in protecting Central Nervous System through inhibited the expression of the caspase3 and caspase9 and increased the expression of the XIAP.