ABSTRACT
AIM: To explore the structural changes of brain microvasculature and mechanism in microvascular lesion after focal cerebral ischemia with reperfusion. METHODS: Using the techniques of immunohistochemical staining, in situ hybridization,optical microscopy and transmission electron microscopy, the expression of uPA, uPA mRNA, and changes in miocrovascular structure were examined in ischemic focus and perifocal areas after focal cerebral ischemia 2 hours with various time points of reperfusion in stroke-prone renovascular hypertensive rats (RHRSP). RESULTS: The brain edema and hemorrhage were severe 12 hours to 3 days after reperfusion. Ultrastructural change showed that the damage characterizations of the basement membrane were degradation, defection, and exfoliated of basement membrane, while uPA, which attack the basememt membrane around cerebral capillaries and extra-cellular matrix, and uPA mRNA expression increased significantly in ischemic and perifocal areas 12 hour to 3 day after reperfusion. CONCLUSION: The main pathologic mechanism of brain edema and hemorrhage after cerebral ischemia with reperfusion may result from the basement membrane lesion of brain microvasculature. The increase in the expression of uPA in reperfusion area may be the main cause of the basement membrane lesion .