Histological dissociation between intra- and extraparenchymal portion of perforating small arteries after experimental subarachnoid hemorrhage in dogs

Ohkuma, H Suzuki, S

H. Ohkuma et S. Suzuki, Histological dissociation between intra- and extraparenchymal portion of perforating small arteries after experimental subarachnoid hemorrhage in dogs, ACT NEUROP, 98(4), 1999, pp. 374-382

26

INGLESE

Article

Neurosciences & Behavoir

ACTA NEUROPATHOLOGICA

0001-6322 → ACNP

98

4

1999

374 - 382

ISI

0001-6322(199910)98:4<374:HDBIAE>2.0.ZU;2-O

This study was conducted to investigate whether the intraparenchymal and ex traparenchymal portions of small cerebral arteries show different histopath ological changes after subarachnoid hemorrhage (SAH). SAH was produced in d ogs by a two-hemorrhage method, and the dogs were perfusion-fixed at 7 and 14 days after SAH. Normal untreated animals were also examined to determine whether or not the histological and morphological changes in the perforati ng arteries were affected by the perfusion pressure during perfusion-fixati on. Control dogs, which received cisternal injection of saline, and untreat ed normal dogs, which were divided into two groups depending on the perfusi on pressure during perfusion-fixation, were also examined. Microvascular co rrosion casts produced by arterial injection of polyester resin were examin ed by scanning electron microscopy (SEM) with morphometric analysis of the caliber of the small perforating arteries. Slices sectioned parallel to the pontine surface were examined by SEM and by light microscopy with morphome tric analysis of the luminal diameter and wall thickness of the small perfo rating arteries. Corrosion casts showed irregular width with folds in the p erforating arteries 7 days after SAH. Sectioned slices showed an increased wall thickness of the perforating arteries with intimal corrugation 7 days after SAH. Morphometric analysis revealed that the extraparenchymal portion of the perforating arteries showed no significant differences between any of the groups tested; however, the intraparenchymal portion showed a signif icant decrease of luminal diameter 7 days after SAH, and a significant incr ease of wall thickness 7 and 14 days after SAH. The perfusion pressure duri ng perfusion-fixation did not affect the histological changes in the perfor ating arteries. The results of this study showed that the vasoconstrictive response of the perforating arteries to SAH was different between the extra parenchymal and the intraparenchymal portion, and showed that the intrapare nchymal portion of the perforating arteries constrict after SAH, which may affect cerebral ischemia during cerebral vasospasm by increasing total cere brovascular resistance.