Study of vascular microdensity in areas of cerebral ischemia on experimental model

Stroke is the third leading cause of death and the first cause of disability with an increasing incidence, especially of the ischemic type. There is no effective curative treatment for stroke and therefore the therapy for this disease currently relies on identifying patients at risk and instituting preventive measures. Since ischemic stroke in middle cerebral artery territory (and with preferential localization in the striated nuclei) is the main type of stroke in humans, animal models obtained by surgical ligation of the middle cerebral artery (MCAO) are valuable tools for the fundamental study of this disease. In this study, we investigated the morphological and immunohistochemical remodeling of the tissue after stroke and in particular the vascular component in a MCAO murine model. The analysis included the sequential sacrificing of animals at 1, 14, 28 and 60 days post-stroke and brain processing for paraffin embedding and sectioning. Our results show a gradual revascularization of the lesion as we move away from the time of the surgical intervention. This effect is accompanied by the development of an increasingly dense glial scar at the periphery of the lesion. The perilesional area itself, the penumbra, is characterized by minimal histological changes (such as eosinophilic neurons), but also by an increased expression of activated caspase 3 as a sign of apoptotic neurons and glial cells. Our study confirms the potential of the organism in its attempt to revascularize the injured area, and raises questions on the role of the glial scar in limiting the process of neovascularization.