Which staining method is used to visualize unsaturated lipids in tissue samples?

Which staining method is used to visualize unsaturated lipids in tissue samples?

• A. H&E
• B. OsO4
• C. Masson's trichrome
• D. Gram stain

Answer: (B)

Visualizing unsaturated lipids relies on a stain that reacts specifically with the carbon–carbon double bonds in fatty acids. Osmium tetroxide does exactly that by reacting with those double bonds to form dark, osmiophilic deposits that highlight lipid-rich areas. This makes structures like myelin, adipose tissue, and other membranes appear distinctly stained, helping lipids stand out in tissue sections. Other stains don’t target unsaturated lipids. Hematoxylin and eosin mainly color nuclei and cytoplasm for general morphology, not lipid content. Masson's trichrome emphasizes connective tissue. Gram stain is used for bacteria. So osmium tetroxide is the correct choice because it directly highlights unsaturated lipids through its chemical reaction with double bonds.

Visualizing unsaturated lipids relies on a stain that reacts specifically with the carbon–carbon double bonds in fatty acids. Osmium tetroxide does exactly that by reacting with those double bonds to form dark, osmiophilic deposits that highlight lipid-rich areas. This makes structures like myelin, adipose tissue, and other membranes appear distinctly stained, helping lipids stand out in tissue sections.

Other stains don’t target unsaturated lipids. Hematoxylin and eosin mainly color nuclei and cytoplasm for general morphology, not lipid content. Masson's trichrome emphasizes connective tissue. Gram stain is used for bacteria. So osmium tetroxide is the correct choice because it directly highlights unsaturated lipids through its chemical reaction with double bonds.