Stroke is one of the leading causes of disability and death globally with a lack of effective therapeutic strategies.
Catalpol is a bioactive compound derived from the
traditional Chinese medicine Rehmannia glutinosa and it has been shown to be protective against various neurological diseases. The potential roles of
catalpol against
ischemic stroke are still not completely clear. In this study, we examined the effect and mechanism of
catalpol against
ischemic stroke using in vivo rat distal
middle cerebral artery occlusion (dMCAO) and in vitro
oxygen-
glucose deprivation (OGD) models. We demonstrated that
catalpol indeed attenuated the neurological deficits caused by dMCAO and improved neurological function.
Catalpol remarkably promoted angiogenesis, promoted proliferation and differentiation of neural stem cells (NSCs) in the subventricular zone (SVZ), and prevented neuronal loss and astrocyte activation in the ischemic cortex or hippocampal dentate gyrus (DG) in vivo. The
vascular endothelial growth factor receptor 2 (KDR, VEGFR-2) inhibitor
SU5416 and
VEGF-A shRNA were used to investigate the underlying mechanisms. The results showed that
SU5416 administration or
VEGF-A-
shRNA transfection both attenuated the effects of
catalpol. We also found that
catalpol promoted the proliferation of cultured brain microvascular endothelial cells (BMECs) and the proliferation and differentiation of NSCs subjected to OGD insult in vitro. Interestingly, the impact of
catalpol on cultured cells was also inhibited by
SU5416. Moreover,
catalpol was shown to protect NSCs against OGD indirectly by promoting BMEC proliferation in the co-cultured system. Taken together,
catalpol showed therapeutic potential in
cerebral ischemia by promoting angiogenesis and NSC proliferation and differentiation. The protective effects of
catalpol were mediated through
VEGF-A/KDR pathway activation.