T. Mori et al., SEQUENTIAL MORPHOLOGICAL-CHANGES OF THE CONSTRICTIVE BASILAR ARTERY IN A CANINE MODEL OF EXPERIMENTAL CEREBRAL VASOSPASM BY TALC INJECTION, Journal of veterinary medical science, 56(3), 1994, pp. 535-540
To demonstrate the possible role of foreign-body reaction to extravasa
ted blood in provoking chronic cerebral vasospasm, talc (crystallized
hydrous magnesium silicate) was injected as a non-biologic foreign mat
erial into the canine cisterna cerebellomedullaris, and pathologic cha
nges were followed. Angiographically, this cisternal talc injection in
duced delayed and prolonged constriction of the basilar artery, withou
t any evidence of so-called early phase cerebral vasospasm that should
occur shortly after an insult. Pathologically, around the spastic art
ery in the subarachnoid space with talc injection, the appearance of a
moderate cellular migration coincided with cerebral vasoconstriction,
which took place 2 days after talc injection. In the spastic basilar
arterial wall, marked constrictive and degenerative changes including
myonecrosis and subintimal proliferation were induced by cisternal tal
c injection as early as on day 2, and the changes were progressive wit
h time. These pathologic changes were extremely analogous to those of
the human autopsy cases with chronic cerebral vasospasm (chronic VS) b
ut more prominent than those observed in the experimental autologous b
lood-induced model. The present study demonstrated that a foreign-body
reaction to talc alone could induce chronic VS in the absence of extr
avasated blood. Thus, it is possible to consider that inflammatory rea
ctions to extravasated autologous blood in subarachnoid hemorrhage may
give rise to chronic VS.