Dendritic
and synaptic plasticity in the penumbra are important processes and are
considered to be therapeutic targets of ischemic stroke. Treadmill
exercise is known to be a beneficial treatment following stroke.
However, its effects and potential mechanism in promoting dendritic and
synaptic plasticity remain unknown. We have previously demonstrated that
the caveolin-1/VEGF signaling pathway plays a positive role in
angiogenesis and neurogenesis. Here, we further investigated the effects
of treadmill exercise on promoting dendritic and synaptic plasticity in
the penumbra and whether they involve the caveolin-1/VEGF signaling
pathway. A middle cerebral artery occlusion (MCAO) animal model was
established, and rats were randomly divided into eleven groups. At
2 days after MCAO, rats were subjected to treadmill exercise for 7 or
28 days. Daidzein (a specific inhibitor of caveolin-1, 0.4 mg/kg) was
used to confirm the effect of caveolin-1/VEGF signaling on
exercise-mediated dendritic and synaptic plasticity. Neurobehavioral
performance, tissue morphology and infarct volumes were detected by
Modified Neurology Severity Score (mNSS), Hematoxylin-eosin (HE), and
Nissl staining, while neural plasticity and its molecular mechanism were
examined by Golgi-Cox staining, transmission electron microscopy,
western blot analysis and immunofluorescence. We found that treadmill
exercise promoted dendritic plasticity in the penumbra, consistent with
the significant increase in caveolin-1 and VEGF expression; improved
neurological recovery; and reduced infarct volume. In contrast to the
positive effects of the treadmill, a caveolin-1 inhibitor abrogated the
dendritic and synaptic plasticity. Furthermore, we observed that
treadmill exercise-induced improved dendritic and synaptic plasticity
were significantly inhibited by the caveolin-1 inhibitor, consistent
with the lower expression of caveolin-1 and VEGF, as well as the worse
neurobehavioral state. The findings indicate that treadmill exercise
ameliorates focal cerebral ischemia/reperfusion-induced neurological
deficit by promoting dendritic and synaptic plasticity via upregulating
caveolin-1/VEGF signaling pathways.
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