Effect of hypertension on blood-brain barrier. Change after restoration of blood flow in post-ischemic gerbil brains. An electronmicroscopic study.

Abstract

SUMMARYThe effect of induced hypertension on the blood-brain barrier (BBB) change in Mongolian gerbils exposed to various periods of ischemia was studied. EVANS blue dye was used to determine the BBB change In animals subjected to different levels of hypertension after 3 h ischemia. Horseradish peroxidase (HRP) was used in electronmicroscopic studies of animals subjected to 30 min, 1,3 or 6 h ischemia and subsequently exposed for 30 min to varying periods and sequences of nonno-and hypertension. Furthermore, HRP-labeled vesicle counts were performed in animals from the 30-min ischemia group.Our findings revealed that hypertension, after blood flow restoration following ischemia, induces and/or accelerates BBB damage by enhancing endotheiial vesicular and/or tubuio-channel transport.Stroke, Vol 11, No 6, 1980WHETHER AN INCREASE of blood pressure has a beneficial effect on the ischemic brain is still a matter of debate in clinical studies.1 -* The ischemic brain has been reported to be highly-resistant to blood-brain barrier (BBB) M change which induces vasogenic edema.8 However, it has been reported that a BBB change can occur after restoration of the blood flow to the ischemic brain. "10 The present study was undertaken to determine how a slight change in blood pressure after blood flow restoration might affect the BBB after ischemia, and to elucidate the ultrastructural mechanisms of this BBB change.The results of this line of inquiry may be of clinical importance in managing patients after the surgical restoration of blood flow to ischemic brain, and in the treatment of cerebral apoplexy without angiographic evidence of vascular obstruction 11 '1J and/or with evidence of rich collateral circulation. Materials and MethodsIschemia was produced in adult Mongolian gerbils of either sex under light ether anesthesia by clipping the left carotid artery with Scovill's aneurysmal clip. Polyethylene tubing (PE 10, Clay-Adams, USA) was inserted through the femoral artery to the abdominal aorta of all ischemia-sensitive animals, selected according to previously described criteria."• M Systemic arterial blood pressure was monitored continuously on a Statham transducer. Under pentobarbital anesthesia (1 mg/100 g body weight, i.p.), 0.1-0.5 mg/kg body weight metaraminol bitartrate was repeatedly injected i.v. to maintain the mean arterial blood pressure (MABP) at different levels of elevation. In each animal, MABP was measured at 5 min intervals after blood flow restoration. BBB Change after 3 h Ischemia Demonstrated by Evans Blue PermeabilityAll animals received an i.v. injection of 0.1 ml/100 g body weight of 2% Evans blue dye immediately before clip release. They were sacrificed 5 min to 5 h thereafter by 10% buffered paraformaldehyde perfusion. Abnormal permeability of the BBB to the dye was assessed by visual inspection of coronal blocks of the perfused brains.The animals were divided into 4 groups according to the different levels of MABP (table). Animals were considered to be positive for BBB change when a blue spot ...

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Inflammatory Markers in Matched Plasma and Cerebrospinal Fluid from Patients with Alzheimer’s Disease

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