| Cerebrovascular diseases are one of the causes of death and disability in the world,and they are closely related to disturbances of blood flow and ischemia. Recent studies found that ischemia brain damage is resulted from many reasons such as functional rearrangement of glia cellsan ion balance disorder,lipid peroxidation induced by free radicals,and changes of neurotransmitters.However the mechanisms underlying ischemia-induced cell death are currently unclar.The neural cell injury after studying a cerebral ischemia the occurrence mechanism and possible intervention factor of the harm,looking for the valid brain protection medicine,utmost reducing a neural cell of impatient and delayed neuronal death,protecting the brain function,are still a little bit hot and crux to study at present.There is the research enunciation,some neural cells of the central nervous system have selectivity to ischemia and is harmful easily.Among them most impressionable to ischemia is hippocampal CA1 region and take place time of the damage at the latest.The research notes that 12 hours after the global cerebral ischemia-reperfusion,the neurons in the rats hippocampal CA1 region has no variety.24 hours, the neurons pyramidal cells ranged regularly,but in the I/R 7 d,the number of normal neuron decreased,the cell body shrank,and the nucleus became out of shape,characterized by hippocampal structure destroyed,cell swelling,cell lysis,pyknotic nuelei,and vacuolization.So there were existed delayed neuronal death in the cerebral ischemia injury.Applying the intervention measure and reducing delayed neuronal death have important meaning.Chinese herbal medicine astragulas what apply history is long,have anti- inflammation,virussafe,anti-decrepitude, adjust-immunity,anti-tumor etc.And some experiment show a conclusion that astragulas have protection function in the global cerebral ischemia-reperfusion injury,being subjected to favor of cure the house.Combine owing to Chinese herbal medicine astragulas to cerebral disease many parts order the function characteristics of the treatment,To study the protective effects of astragulas against the whole cerebral ischemia and reperfusion injury and its mechanisms,becomes current medical science realm to study of a little bit hot.The research purpose of this experiment: Applications was established by four-vessel cerebral ischemia-reperfusion injury model to observe the cerebral ischemia-reperfusion 7 days,hippocampal CA1 neurons morphological and ultrastructural changes, the number of survival cells and apoptosis rate of change, and Cortex apoptosis-related protein P53, Bcl-2 expression changes.And application of astragalus to intervene, to change these indicators to compare and explore Astragalus reduce cerebral ischemia-reperfusion injury mechanism for Astragalus theoretical basis for clinical applications.Experimental methods:In this experiment we applicate the SD rat whose cost is low and who growing to fasten purely match sex good,its cerebral with mankind of the characteristic likeness to be used as the experiment animal;We adopt Pulsinelli four vessels occlusion for 15 min and reperfusion for 7d in rats.This experiment was performed to evaluate effects of astragulas injection.48 rats were randomly assigned to sham group,I/R model group,nimodipine group and astragulas injection group. And select the application of HE staining were observed under the optical microscope, hippocampal CA1 neurons in morphological changes and survival neuron counts;application of electron microscopy ultrastructure of hippocampal CA1 area;application of flow cytometry in hippocampal neuronal apoptosis rate; biochemical test kit cerebral ischemia in the cerebral cortex 7 days P53, Bcl-2 expression. Operations carried out in strict accordance with instructions.Examination result: (1)The morphologic characteristics of neurons in the rat hippocampal CA1 region:Sham group:In there were 3～4 layers neurons ranged regularly in hippocampal CA1 region,the nuclcus was big,round,and pellucid,which can be seen 1～2 nucleolus clearly.I/R model group: Neurons disordered and loose, wrinkled appearance, some cells drop out, deeply stained nuclear condensation, cytoplasmic cavitation, nuclear dissolution, nuclear realm unclear;neuron counts were significantly lower than the normal control group(P<0.01).Nimodipine group and Astragulas injection group: Most of the neurons to maintain a normal shape, cell arrangement of the basic rules,some intracellular staining, become darker in the majority of the remaining neurons was reversible ischemic changes in neurons counts were significantly higher than the I/R model group(P<0.01). (2) Hippocampal CA1 area ultrastructural changes of nerve cells: Sham group: 7 days after the neuron nucleus was oval, two clear and smooth membrane, perinuclear space uniform, evenly distributed nuclear chromatin, abundant cytoplasmic organelles,structural integrity, we can see the distribution of Golgi structure was parallel flat vesicles, mitochondria were round, oval shape, clearly visible cristae, matrix uniform, rough endoplasmic reticulum arranged in parallel, or scattered in a large number of glycogen particles present in the cell Pulp.I/R model group: nuclear membrane structure fuzzy,mitochondrial vacuolization evident, and the more heavier, irregular Golgi. Nimodipine group and Astragalus injection group compared with the I/R model group, hippocampus lesions lighter cytoplasmic organelles rich organelle structure is more complete, some degeneration of organelle structure. (3)Hippocampal neuronal apoptosis rate: Compared with sham group, neuronal apoptosis rate in I/R model group was obviously increased(P<0.01); Compared with I/R model group, Nimodipine group and Astragalus injection group of neuronal apoptosis rate was significantly reduced (P<0.01). Compared with nimodipine group, Astragalus injection group neuronal apoptosis rate was no significant change(P>0.05).(4) Cortex apoptosis-related protein P53, Bcl-2 expression: Sham group: P53 expression was not changed significantly, Bcl-2 expression of the more obvious. Compared with sham group, I/R Model group P53 expression was significantly increased, Bcl-2 expression was significantly reduced (P<0.01). Compared with I/R Model group,Nimodipine group and Astragalus injection group P53 expression were significantly inhibited, Bcl-2 expression were significantly increased(P<0.01). Compared with nimodipine group, Astragalus injection group P53, Bcl-2 expression was no significant change(P>0.05).Conclusion: Astragalus can significantly improve the cerebral ischemia-reperfusion in hippocampal CA1 neurons after the morphological and ultrastructural changes, reduction of neuronal loss, reduce the hippocampal neuronal apoptosis rate, reduce the expression of P53, increased expression of Bcl-2. Astragalus can protect the brain tissue.
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