| With recent progress in machanism of cerebral ischemic damage, neuroprotective therepy has been an innovative conception in clinical therepy. The synthetic and release of excitory amino acids are greatly increased after cerebral ischemia and the balance btween excitory amino acids and inhibitory acids are broken. With the increase of excitory amino acids after cebral ischemia, the concentration of inhibitory acids such as γ-amino acid has been also increased to resist the toxicity of the excitory amino acids .The γ-aminobutyric acid is synthesized from glutamate in a reaction catalyzed by glutamic acid dezarboxylase (GAD). GAD is the rate-limiting enzyme and can directly affect the concentration of GABA in the brain. GAD is distinctively located in the end of GABAergic neurons and distributed consistently to the GABAergic neurons in the brain. GAD can be regarded as the distinct mark of the GABAergic neurons. Only GABAergic neurons is posotive in the expression of GAD. GADmRNA can be the mark of the survival of the GABAergic neurons, and the GADmRNA is more steady than GABA in the brain. The level of transcription of GADmRNA is consistent to the immuniactivites of it, so we can measure the activities of GAD or the amount of the GAD+ neurons to reflect the function of GABAergic neurons in the central nervous system. GABA is resitent to the toxicity of the excitory amino acids because it can promote the conduct of Cl-, prevent the depolarization of the postsynaptic inhibition effectively and the open of Ca2+-gated channel, reduce the metabolic rate of the ischemic nurons. The gene expression of vascular endothelial growth factor is very low in the common tissue of the humans and annimals, but can be evoked in the pathological conditions such as the cerebral ischemia. VEGF can increase the proliferation of the endothelial cell, induce the angiogenesis, prevent the disappearance of the capillary vessel and the programmed death of endothelial cell, stimulate the growth of axon. VEGF is neuroprotective to the ischemic neurons. Methods: 168 healthy Wistar rats (weight from 250g to 300g) were recruited to establith the middle cerebral artery occlusion (MCAO) model by the ligation of the right carotid artery. The focal ischmic tissue was fixed, dehydrated, and paraffin-embedded in regular way at the time 6h, 1d, 3d, 5d, 7d, 14d after the occlusion of MCA respectively. The gene expression of GAD in focal ischemic tissue of different times after MCAO was assayed by in situ hybridization (ISH). We also used RT-PCR method to detect the expression of VEGF. The neurological defects and cerebral pathological changes are observed. Results: The results of ISH and RT-PCR revealed that the expression of GAD mRNA and VEGF mRNA is not so high in the common brain tissue. The gene expression of GAD,VEGF in the controlled and treatment group increased from 6h after the MCAO, and reached their peaks at the time of 72/24h after ischemia respectively, then declined gradually. The gene expression of GAD was higher than normal after 2 weeks, but the gene expression of VEGF became normal after 7 days. The gene expression of GAD,VEGF in the treatment group is more than that of controlled group. Conclusion: Puerarin can ease the neurological defects of the animal models, ameliorate the pathological changes of the ischemic tissues, promote the gene expression of GAD and VEGF. It is neuroprotective and is good to the rehibition of the neurological function. Puerarin is widely used in the prevention and treatment of cardiocerebralvascular diseases in the recent years because it can ameliorate microcirculation, increase the blood supply of the focal tissues. It also can prevent the production of the free radicals and has neuroprotective effects. The experiment focused on the recent development of the studies of focal cerebral ischemia, and studied further on the expression of GAD and VEGF in the focal cerebral ischemia of MCAO model using modern molecular biological techniques. The gene express...
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