Abstract
Hypertension results in microvascular rarefaction in various organs. In this study,
we investigated the pathogenesis of microvascular rarefaction in hypertensive rat
brain. Light microscopy of the arterioles showed hyalinosis and fibrinoid changes.
X-ray images of rat brain injected with barium exhibited a decrease of microvessels.
Scanning electron microscopy using casting method showed a decrease of microvessels
and the presence of blind end structures. Scanning electron microscopy without casting
method showed leukocyte and platelet adhesion to the endothelial cells of arterioles.
Transmission electron microscopy of the hypertensive rat arterioles revealed fibrinoid
deposits in the intima with luminal narrowing and thrombotic occlusion. The muscle
cells in the arteriolar media had disappeared, and cell debris and a lamellarly increased
basement membrane were observed. The capillaries of the hypertensive rats sporadically
showed collapse and thrombotic occlusion. The basement membrane of the capillaries
was mildly thickened and occasionally duplicated. The pericytes of hypertensive rats
showed irregular profile, islet-like fragmentation of their cytoplasmic processes
and large defect of them around the capillaries. The basement membrane of the pericytes
was thickened, and rarely found cell debris in it. We conclude that microvascular
rarefaction in hypertensive rat brain results from both an elevated arteriolar and
capillary pressure, which induces secondary arteriolar, capillary, and pericyte lesion
via overperfusion. Copyright © 2003 by National Stroke Association
Keywords
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Article info
Publication history
Accepted:
October 14,
2002
Received in revised form:
October 10,
2002
Received:
August 13,
2002
Footnotes
*Address reprint requests to: Keiji Suzuki, MD, Division of Histopathology, Department of Laboratory Sciences, Gunma University School of Health Sciences, 3-39-15 Showamach, Maebashi, Gunma 371-8514, Japan.
Identification
Copyright
© 2003 National Stroke Association. Published by Elsevier Inc. All rights reserved.
