Confocal microscopic characterization of a lesion in a cerebral vessel of the stroke-prone spontaneously hypertensive rat.
OBJECTIVE
Hypertension is a major risk factor for stroke and is associated with alterations in vascular structure and function. The aim of this study was to determine vascular function, wall morphology, and vascular smooth muscle cell (VSMC) arrangement in basilar arteries from stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive control strain Wistar-Kyoto rats (WKY). The effect of perindopril treatment on SHRSP structure and function was also assessed.


METHODS
VSMC orientation was determined with laser-scanning confocal microscopy and computer-assisted image processing in basilar arteries stained with 5(6)-carboxyfluorescein (wavelengths: excitation, 488; emission, 515) or propidium iodide (excitation, 529; emission, 550). Measurements of wall morphology and functional responses to serotonin and KCl were assessed with wire myography.


RESULTS
In the WKY basilar arteries, VSMCs were uniformly oriented perpendicular to the longitudinal axis of the vessel, whereas in the SHRSP there were localized foci of VSMC geometric disorganization, with a significant deviation from 90 degrees. The SHRSP basilar arteries also showed structural remodeling and reduced contractile responses to serotonin and KCl. Perindopril treatment normalized blood pressure, prevented wall morphology alterations, and improved function but had no effect on VSMC disorganization.


CONCLUSIONS
This is the first demonstration of lesions of VSMC geometric disorganization in a cerebral artery from a stroke-prone genetically hypertensive rat strain. These structural abnormalities are independent of blood pressure. Their functional sequel may play a role in the pathogenesis of stroke in this model.
Arribas
S M
SM
Clinical Research Initiative in Heart Failure, University of Glasgow, UK. s.arribas@biomed.gla.ac.uk
Gordon
J F
JF
Daly
C J
CJ
Dominiczak
A F
AF
McGrath
J C
JC
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001488:Basilar Artery / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects; D002561:Cerebrovascular Disorders / Q000473:pathology* / Q000503:physiopathology; D004396:Coloring Agents; D005260:Female; D005452:Fluoresceins; D005456:Fluorescent Dyes; D007091:Image Processing, Computer-Assisted; D007211:Indoles / Q000494:pharmacology; D008297:Male; D018613:Microscopy, Confocal; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D020913:Perindopril; D011189:Potassium Chloride / Q000494:pharmacology; D011419:Propidium; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012701:Serotonin / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D004396:Coloring Agents; D005452:Fluoresceins; D005456:Fluorescent Dyes; D007211:Indoles; D014662:Vasoconstrictor Agents; C024098:6-carboxyfluorescein; D012701:Serotonin; D011419:Propidium; D011189:Potassium Chloride; D020913:Perindopril