Effects Of Puerarin On The Expression Of MMP-2,MMP-9 After Focal Ischemic Damage In Rats

Ischemic cerebralvascular disease is a common disease with high morbidity and death rate.Vasogenic brain edema (VBE) is very important pathological change after cerebral ischemia, which can aggravate the ischemic damage. The VBE can be caused by the damage of blood brain barrier (BBB). BBB is made up of cerebral microvascular endothelial cell, basal lamina and neuroglia. The basal lamina and extracellular matrix (ECM) in the intercellular substance is important structure in keeping the integrity of the BBB. Matrix metalloproteinase (MMP) is a family of proteolyticthe enzyme which can resolve the ECM. MMP-2, MMP-9 play important role in the pathology of the cerebralvascular disease. In the commom brain tissue, the expression of MMP is low. The gene expression of MMP gets increase in the pathological condition. Focal ischemia can cause the change of permeability of the basal lamina. The degradation of the basal lamina can cause the cell edema and death. The loss of the basal lamina is the most important cause of microvascular hemorrhage. MMP destroy and get the BBB open to cause the brain edema. At the same time, it can destroy the extracellular matrix and cause the death of the neurons. The excessive expression of MMP plays important role in the destroy of BBB and VBE.The Anti-MMP antibody can lessen the ischemic damage. 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. But the mechanism of the neuroprotective effects is not sure. In this project, we take the molecular technology to explore the mechanism to its neuroprotective effects. 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 MMP-2,MMP-9 in focal ischemic tissue of different times after MCAO was assayed by RT-PCR. The neurological defects and cerebral pathological changes are observed. Results: The results of RT-PCR revealed that the expression of MMP-2mRNA and MMP-9mRNA is low in the common brain tissue. The gene expression of MMP-2mRNA and MMP-9mRNA in the controlled and treatment group increased from 6h after the MCAO, and reached their peaks at the time of 5d/72h after ischemia respectively, then declined gradually. The gene expression of MMP-2mRNA and MMP-9mRNA was normal after 2 weeks. The gene expression of MMP-2mRNA and MMP-9mRNA in the treatment group is less than that of controlled group. Conclusion: Puerarin can ease the neurological defects of the animal models, ameliorate the pathological changes of the ischemic tissues, reduce the gene expression of MMP-2mRNA and MMP-9mRNA. It is neuroprotective and is good to the rehibition of the neurological function. The experiment focused on the recent development of the studies of focal cerebral ischemia, and studied further on the expression of MMP in the focal cerebral ischemia of MCAO model using modern molecular biological techniques. The gene expression of MMP-2 and MMP-9 in the treatment group is less than that of controlled group. Combined with our experiment, we are certain that Puerarin has neuroprotective effects to the ischemic damage. Further study of the mechanism of how Puerarin functions in the focal ischemia and then exploring new effective ways to treat cerebralvascular diseases in the early stage is our next aim.