Investigating the impact of subchronic exposure to e-cigarette vapor on occludin expression in the blood-CSF barrier of C57BL6/J mouse.

E-cigarette (EC) usage is a significant public health concern; however, its effects on various organ systems, including the brain, remain poorly understood. Despite this, studies are beginning to link EC usage to downregulation of tight junctions (TJ) in epithelial barriers. Occludin is a TJ protein that plays a key role in maintaining blood-CSF barrier (BCSFB) integrity and selective permeability. Downregulation of TJ proteins, including occludin, help regulate paracellular transport across the choroid plexus epithelium. Dysregulation of this barrier can compromise brain homeostasis. This study investigated the impact of subchronic EC vapor exposure on occludin within the BCSFB of C57BL6/J mice. Brains from adult males and females exposed to tropical rainbow blast-flavored EC vapor were processed for occludin immunohistochemistry. Periventricular regions will be imaged using a Motic BA210E compound microscope at 40x. Integrated density values were determined using imageJ to compare occludin levels. We hypothesize that treatment mice will have lower integrated density values than controls, indicating possible BCSFB disruption following subchronic EC vapor exposure.