A novel methodology for NETs visualization under light microscopy

Neutrophils are the most abundant leukocytes in the bloodstream and are very important for the resolution of infection. One of the strategies used by neutrophils to eliminate a microorganism is the formation of extracellular traps. Different methods for neutrophil extracellular traps (NETs) visualization have been described along the years, usually requiring the use of a fluorescent, confocal or scanning electron microscope. This research aimed to visualize NETs using light microscopy as another way to study NETs prior to using the more expensive techniques, making NETs research more cost effective. We evaluated neutrophil purity, viability and function by analyzing the formation of NETs comparing DAPI with safranin. When evaluating NETs formation, neutrophils that were not stimulated did not form NETs and when neutrophils were exposed to PMA or S. aureus NETs were formed and visualized with safranin under light microscopy and DAPI under fluorescence microscopy. Our method demonstrates another way to visualize NETs that can be added to the standard methods of visualization of NETs, increasing the opportunities to generate knowledge in the topic in any lab around the world.