Figure 2

Blood brain barrier integrity in organotypic slices. (A) Schematic representation of the NVU. Brain vessels are composed of endothelial cells joined together by TJ proteins namely ZO-1, claudin-5 and occludin but also by adherens junctions (AJs) with cadherin/catenin complex. Occludin and claudin-5 are membrane proteins responsible for junction formation and ionic transport. ZO-1 and catenin bind membrane proteins and actin. ZO-1 is responsible for the presence of TJ proteins at the membrane. Endothelial cells are surrounded by end-feet of astrocytes and by pericytes, both essential for the maintenance and regulation of the NVU. Neurons and microglia are also present in the NVU. Many transporters are present at the BBB, including P-glycoprotein (P-gp) and Glucose transporter-1 (Glut-1). All transporters are involved in nutrient passage and brain detoxification, and play an important role in the pharmaco-resistance. (B) Blood vessel (laminin- red) and astrocyte (GFAP- green) staining in control slices, or 24 hours after treatment with bicuculline or kainate. Arrows represent astrocyte end-feet. Scale bar: 50 μm. (C) Quantification of western blot for claudin-5, occludin and ZO-1, 24 hours after bicuculline or kainate seizures. Results are expressed in percent of control. ** p<0.01 (D) Photomicrographs of ZO-1 (green) and laminin (red) staining in control slices and 24 h after bicuculline or kainate in vitro seizures. Scale bar: 10 μm.