Dynamics of dystroglycan complex proteins and laminin changes due to angiogenesis in rat cerebral hypoperfusion

Permanent bilateral carotid occlusion is a well known cerebral hypoperfusion model in rats. The aim of our study was to investigate the different stages of vascular reaction by detecting changes in the extracellular martix proteins and to examine their relationship to angiogenesis after occlusion. Experiments were performed on adult male rats. Brain samples were investigated from day 1 to day 30 post-surgery. Immunohistochemical analysis was performed on the whole hippocampus and on the adjacent cortex in order to investigate extracellular martix proteins, such as the markers of dystroglycan complex (β-dystroglycan, α-dystrobrevin and utrophin) and a marker of basal lamina (laminin). The levels of the proteins were estimated by western blot analysis. Vascular density as well as blood-brain barrier permeability were studied on brain slices from the same regions. Our results showed altered laminin and β-dystroglycan immunoreactivity beginning 2 days after the onset of occlusion followed by an increased utrophin immunoreactivity without blood-brain barrier disruption 5 days later. By day 30 of hypoperfusion, when increased vascular density was detected, all changes returned to baseline levels. Western blot analysis showed significant differences in β-dystroglycan and utrophin expression. Our results indicate that the different stages of neovascularisation resulting from cerebral hypoperfusion can be well defined by the markers laminin, β-dystroglycan, and utrophin and that these markers are more likely to correlate with glio-vascular decoupling than does altered blood-brain barrier function.