Structural alterations of resistance vessels of spontaneously hypertensive rats and protective effects of captopril.
OBJECTIVE
To observe the structural alterations of resistance vessels in spontaneously hypertensive rats (SHRs) and to evaluate the effects of captopril on them.


METHODS
15-week-old male SHRs were treated with oral captopril (100 mg/kg/day) for 12 weeks. Age- and sex-matched SHRs and Wistar-Kyoto rats (WKY) were fed under the same conditions without captopril administration for the same duration. All rats were killed at the age of 27 weeks. The structural parameters included media width, lumen diameter, media-lumen ratio, vascular collagen area (VCA) and vascular collagen density (VCD). The media width, lumen diameter and media-lumen ratio were measured in hhematoxylin and eosin staining sections under a direct light microscope and VCA and VCD in picrosirius red staining sections under a polarizing light microscope. All the values were processed with a computer image analyzer.


RESULTS
There were thicker media width, smaller lumen diameter, higher media-lumen ratio and larger VCA in untreated SHRs than in WKY. Captopril inhibited media thickening, with lumen diameter decreasing, media-lumen ratio increasing and VCA enlarging. There was no significant difference in VCD among the three groups.


CONCLUSIONS
Adverse structural alterations occur in resistance vessels of SHRs and captopril may prevent their progression.
Chen
Y
Y
Department of Cardiology, Rui Jin Hospital, Shanghai Second Medical University.
Gong
L
L
Yu
J
J
Gu
D
D
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D002216:Captopril / Q000494:pharmacology*; D003094:Collagen / Q000378:metabolism; D006973:Hypertension / Q000473:pathology*; D007091:Image Processing, Computer-Assisted; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000473:pathology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D014655:Vascular Resistance
D000806:Angiotensin-Converting Enzyme Inhibitors; D003094:Collagen; D002216:Captopril