Oil Red O (CAS 1320-06-5)

Oil Red O is a lysochrome (fat-soluble dye) predominantly used in histology for staining neutral triglycerides and lipids in tissues, marking it as a valuable tool in the study of fat metabolism and storage within cells. This diazo dye is insoluble in water but soluble in fats and alcohols, which explains its specificity for lipid-rich environments. The staining mechanism of Oil Red O involves the physical adherence of the dye to lipid droplets within cells or tissues, facilitated by its solubility properties. When applied to a sample, typically a frozen tissue section, Oil Red O is usually dissolved in a mixture of isopropanol and distilled water, which helps it to stain lipid structures red, while the nuclei are often counterstained with hematoxylin for contrast. This specific affinity for lipids makes Oil Red O a critical stain in the identification and visualization of adipocytes (fat cells) and other lipid-containing cells in research focused on obesity, lipid metabolism disorders, and other conditions involving lipid accumulation. Furthermore, its application extends into nutritional studies where it helps delineate the effects of various diets on fat storage. Oil Red O has also found utility in the examination of atherosclerotic plaques, providing insights into the lipid composition of these plaques which are pivotal in cardiovascular research. Thus, Oil Red O serves as an essential staining agent in both basic biological research and broader studies of pathological processes involving lipid dynamics.