title: Rapid microvessel rarefaction with elevated salt intake and reduced renal mass hypertension in rats.
abstract: To identify the sequence of events associated with the development of reduced vessel density (rarefaction) in hypertension, microvessel density and ultrastructure were assessed in the cremaster muscle of rats subjected to a 75% surgical reduction of renal mass and normotensive sham-operated control rats. Rats with reduced renal mass (RRM rats) and sham-operated rats were then maintained on either a high salt (4.0% NaCl) or a low salt (0.4% NaCl) diet for 3 days. Acute exposure to the high salt diet significantly increased mean arterial pressure in RRM rats but did not affect sham-operated control rats. Quantitative fluorescence microscopy of cremaster muscle whole mounts using rhodamine-labeled Griffonia simplicifolia I lectin revealed substantial rarefaction of microvessels in both RRM hypertensive rats and normotensive sham-operated rats on a high salt diet relative to corresponding control rats on a low salt diet. Confocal microscopy revealed a heterogeneous distribution of microvessels in RRM rats on a high salt diet, with some areas largely devoid of vessels. RRM and sham-operated rats on a high salt diet both exhibited changes in arteriolar ultrastructure, which included a loss of basement membranes and a dissociation of the endothelial and smooth muscle components of the vascular wall, resulting in a loss of vessel integrity. These observations demonstrate that a rapid loss of microvessels can occur not only in rats with RRM hypertension but also in normotensive rats on a high salt diet. This loss of microvessels results from structural alterations, which differ from the degenerative processes associated with microvascular rarefaction in rats with chronic RRM hypertension.
authors: Department of Physiology, Medical College of Wisconsin, Milwaukee 53226, USA.
authors: F M
authors: FM
authors: Hansen-Smith
authors: L W
authors: LW
authors: Morris
authors: A S
authors: AS
authors: Greene
authors: J H
authors: JH
authors: Lombard
mesh_terms: D000818:Animals; D001794:Blood Pressure; D001808:Blood Vessels / Q000473:pathology; D001835:Body Weight; D006339:Heart Rate; D006973:Hypertension / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009132:Muscles / Q000098:blood supply*; D009392:Nephrectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D012965:Sodium Chloride