Blood-brain Barrier Permeability And Matrix Metalloproteinase-9 Expression In A Rat Model Of Vascular Cognitive Impairment

Partâ… Blood-brain barrier permeability and matrix metalloproteinase-9expression in a rat model of vascular cognitive impairment Objective: To observe blood-brain barrier (BBB) permeability and matrix metalloproteinase-9 (MMP-9) expression in a rat model of vascular cognitive impairment.Methods: Male Wistar rats were randomly divided into 2 groups as following: chronic cerebral hypoperfusion group (performed by bilateral common carotid artery ligation), and normal group. BBB permeability was observed by injecting with horseradish peroxidase (HRP) as an indicator of BBB function. Levels of MMP-9 were measured by immunohistochemistry. The changes of hippocampal neurons and neurofibrillary were observed by HE stain and the modified Bielschowsky silver stain.Results: Compared with the normal rats, the reaction product of HRP and expression of MMP-9 were most intensely localized to the vessels in the hippocampal fissure of the model groups, and occurred to a small degree at 3 hours, 24 hours, 48 hours, markedly on days 3, but reduced on days 7 and 14. We also discovered the degeneration of hippocampal neurons and neurofibrillary.Conclusion: In a rat model of vascular cognitive impairment, expression of MMP-9 increased, which is related to the BBB disruption and the degeneration of hippocampal neurons and neurofibrillary. Partâ…¡MMP-9 plays a critical role in blood-brain barrier disruption in a rat model of vascular cognitive impairmentObjective: To determine the role of matrix metalloproteinase-9 (MMP-9) in blood-brain barrier (BBB) disruption in a rat model of vascular cognitive impairment.Methods: Male Wistar rats were randomly divided into 3 groups as following: chronic cerebral hypoperfusion group (performed by bilateral common carotid artery ligation), BB-94 treatment group (50 mg/kg, bid, ip) and normal group. After 3 days, BBB permeability was observed by injecting with horseradish peroxidase (HRP) as an indicator of BBB function; Levels of MMP-9 were measured by immunohistochemistry; the changes of hippocampal neurons were observed by HE stain. These models were checked by using Morris water maze for behavior ability of learning and memory on the 1 month after operation.Results: Compared with the model rats, the reaction product of HRP was significantly lower, the degeneration of hippocampal neurons was significantly less severe, and the result of water maze experiment was improved in BB-94 treatment group. Compared with the normal rats, the reaction product of HRP, hippocampal neurons, and the escape latency time were not significantly changed in BB-94 treatment group.Conclusion: In a rat model of vascular cognitive impairment, the higher expression of MMP-9 can promote the damage of the BBB and the degeneration of hippocampal neurons, which contribute to cognitive dysfunction. MMP-9 inhibitor can protect the BBB, and checks development of disease.