Morphologycal and morphometric analysis of Sural nerve in newly weaned spontaneously hypertensive rat (SHR) compared with normotensive Wistar Kyoto rat (WKY)

Abstract

Previous data from our laboratory showed that the sural nerve from 20 weeks old spontaneously hypertensive rat (SHR) present alterations of myelinated fibers and endoneural vessels. To investigate whether these differences were caused by hypertension or were due to strains differences, the aim of the present study was to compare the aspects of the sural nerve from newly weaned SHR, which had not developed hypertension, with WKY. Rats aged 5 weeks (N=6 in each group) were used. After arterial pressure and heart rate recordings, right and left sural nerves were removed and prepared for light microscopy. Morphometric analysis was performed with the aid of computer software. Arterial pressure levels were similar between SHR and WKY. There were no differences in morphological and morphometric parameters of fascicular area, myelinated fiber number and density in both strains. Nevertheless, the morphometric parameters of myelinated fibers were different between SHR and WKY, despite no alterations on the endoneural vascularization in both strains. These results are suggestive of intrinsic differences on the myelinated fibers between SHR and WKY even before the development hypertension.