Basic NeuroscienceIn situ demonstration of Fluoro-Turquoise conjugated gelatin for visualizing brain vasculature and endothelial cells and their characterization in normal and kainic acid exposed animals

•The Fluoro-Turquoise conjugated gel (FT-gel) is a UV excitable dye that labels all the microvessels in the brain.•This fluorescent dye does not bleed through other filters making it ideal for multiple labeling studies.•Its intense brightness at low magnifications makes it ideal for whole brain imaging at low magnification.•FT gel is an ideal marker for neurovascular damage because of its ability to show changes following neurotoxic insult.

The present study describes a new method for the visualization of the vasculature lumen and endothelial cells and characterizes their morphology in the brains of normal and kainic acid (KA) treated rats. Herein, labeling was accomplished using Fluoro-Turquoise (FT), a novel reactive blue fluorochrome conjugated to gelatin. Strong blue fluorescence was observed throughout the brain vasculature following intra-cardiac perfusion with FT-gel in normal animals. However, in the brains of KA treated rats (hippocampus, midline and ventral thalamus, piriform cortex), the vascular lumen was typically constricted, sclerotic and only faintly stained. The advantages of FT-gel over other markers can be attributed to its unique chemical and spectral properties. Specifically, Fluoro-Turquoise is a very bright blue UV excitable dye that does not bleed through when visualized using other filters, making it ideal for multiple immunofluorescent labeling studies. Its brightness at low magnification also makes it ideal for low magnification whole brain imaging. Compared to alternative techniques for visualizing blood vessels, such as India ink, fluorescent dye-conjugated dextran, the corrosion technique, endothelial cell markers and lectins, the present method results in excellent visualization of blood vessels.