Wall thickness to lumen diameter ratios of arteries from SHR and WKY: comparison of pressurised and wire-mounted preparations.
Passive properties (diameter, wall-to-lumen ratio and axial length) of small mesenteric arteries from SHR and WKY rats were measured with the artery segments cannulated and pressurised, or mounted on wires in a myograph. The measurements were made with a range of distending pressures (or calculated equivalent distending pressures when wire-mounted) from 0 to 180 mm Hg. The axial length of artery segments increased with increasing distending pressure when cannulated, but not when wire-mounted. The axial extension was greater for arteries from WKY (up to 105%) than for arteries from SHR (up to 65%). The arteries from SHR had significantly smaller diameters and greater wall-to-lumen ratios than the arteries from WKY. However, the diameters calculated for the arteries when wire-mounted were less than the measured diameters, and the wall-to-lumen ratio was always greater when wire-mounted than when cannulated because of the underestimated diameter and the absence of axial extension. Wall-to-lumen ratios decreased with increased distending pressure; values at 180 mm Hg were only 18 and 25% of those at 0 mm Hg for WKY and SHR arteries, respectively. The large degree of variability of wall-to-lumen ratios obtained from the two different preparations and the large range of values that are obtained from a single artery at different distending pressures must call into question the validity of characterising vascular hypertrophy by any single estimation of this parameter.
Lew
M J
MJ
Baker Medical Research Institute, Prahran, Australia.
Angus
J A
JA
D000818:Animals; D001699:Biometry; D001794:Blood Pressure; D006984:Hypertrophy / Q000473:pathology; D008638:Mesenteric Arteries / Q000033:anatomy & histology*; D051381:Rats; D011918:Rats, Inbred SHR / Q000033:anatomy & histology*; D011921:Rats, Inbred WKY / Q000033:anatomy & histology*