Postnatal development of the visual cortex is modulated by experience, especially during the critical period. In rats, a stable
neuronal population is only acquired after this relatively prolonged period. Vascular endothelial growth factor (VEGF) is
the most important angiogenic factor and also has strong neuroprotective, neurotrophic and neurogenic properties. Similar
effects have been described for rearing in enriched environments. Our aim is to investigate the vascular and neuronal effects
of combining VEGF infusion and environmental enrichment on the visual cortex during the initial days of the critical period.
Results showed that a small percentage of Cleaved Caspase-3 positive cells colocalized with neuronal markers. The lesion produced
by the cannula implantation resulted in decreased vascular, neuronal and Caspase-3 positive cell densities. Rearing under
enriched environment was unable to reverse these effects in any group, whereas VEGF infusion alone partially corrected those
effects. A higher effectiveness was reached by combining both the procedures, the most effective combination being when enriched-environment
rearing was introduced only after minipump implantation. In addition to the angiogenic effect of VEGF, applied strategies
also had synergic neuroprotective effects, and the combination of the two strategies had more remarkable effects than those
achieved by each strategy applied individually.
Keywords Critical period – Enriched environment – Neuroprotection – Neurovascular unit – VEGF – Visual system