Which stain is used to visualize neutral fats that appear pinkish red?

Sudan IV is a dye specifically designed to visualize neutral fats within tissues. This stain is hydrophobic, allowing it to dissolve in lipids, which results in fatty tissues and structures becoming distinctly colored. When tissues containing neutral fats are stained with Sudan IV, they typically appear pinkish-red, which can be easily recognized under a microscope.

This property makes Sudan IV particularly valuable in histopathological studies where lipid content is of interest, such as assessing adipose tissue or identifying fat deposits in pathological conditions. Other staining methods listed are used for different types of cellular components, and do not specifically stain neutral fats. For example, Nile blue sulfate is used primarily for identifying cellular structures based on their lipid content, but it does not produce the characteristic pinkish-red color associated with neutral fats. The Feulgen stain is focused on DNA visualization, while Rhodamine B is typically used for fluorescent staining of proteins and other biomolecules, making Sudan IV the most appropriate choice for visualizing neutral fats.