Comparisons of Cutaneous Microvessels from Spontaneously Hypertensive, Normotensive Wistar-Kyoto, and Normal Wistar Rats

Abstract

Samples of abdominal skin from SHR [spontaneously hypertensive], WKY [Wistar-Kyoto] and NW [normal Wistar] rats were examined to determine if gross strucural differences were apparent among the cutaneous vascular beds of the 3 strains of rats, and if the structural differences were generalized or localized to a specific level of the vascular tree. The most significant differences among the 3 strains of rats were at the level of the smallest (4th-order) arterioles. The SHR had 30% fewer of the smallest arterioles than WKY and 38% fewer than NW. The smallest arterioles from SHR had diameters 22 and 26% larger than similar vessels from WKY and NW, respectively. There were no significant differences in calculated resistance among vessels from the 3 strains of rats. No significant differences were found in the vessel branching angles among the 3 strains of rats. It could not be determined from these studies whether the genetic mechanism responsible for the differences in arteriolar numbers and diameters observed among these highly inbred strains of rats was related to the genetic mechanism responsible for hypertension in SHR.