Neurogenesis and angiogenesis are two important processes that may contribute to the repair of
brain injury after
stroke. This study was designed to investigate whether
transplantation of human embryonic neural stem cells (NSCs) into cortical peri-
infarction 24h after
ischemia effects cell proliferation in the subventricular zone (SVZ) and angiogenesis in the peri-
infarct zone. NSCs were prepared from embryonic human brains at 8 weeks gestation. Focal
cerebral ischemia was induced by permanent occlusion of the middle cerebral artery of adult rats. Animals were randomly divided into two groups (
n=30, each) at 24h after
ischemia: NSC-grafted and medium-grafted groups.
Toluidine blue staining and 5'-bromo-2'-deoxyuridine (
BrdU) or
von Willebrand factor (vWF) immunohistochemistry were performed at 7, 14 and 28 days after
transplantation. NSC
transplantation increased the number of
BrdU-positive cells in the ischemic ipsilateral SVZ compared with the medium control at 7 days (P<0.01). This difference in SVZ cell proliferation persisted at 14 days (P<0.01), but was not significant at 28 days (P>0.05). In addition, angiogenesis, as indicated by
BrdU and vWF staining in cortical peri-
infarct regions, was augmented by 46% and 65% in NSC-grafted rats versus medium-grafted rats at 7 and 14 days, respectively (P<0.05). However, this increase became non-significant at 28 days (P>0.05). Our results indicate that NSC
transplantation enhances endogenous cell proliferation in the SVZ and promotes angiogenesis in the peri-
infarct zone, even if it is performed in the acute phase of ischemic injury.