A method to fix lipids for staining fat embolism in paraffin sections

Abstract

To develop a method to preserve lipids in formalin-fixed tissues for staining in paraffin sections, and to illustrate its use in lung and brain of a fat embolism case, and in examples of fatty liver and atheroma. A saturated solution of linoleic acid in 70% ethylene glycol was prepared and tissues were exposed to this for 3 days at 56 degrees C. These tissues were treated with 2% chromic acid at 4 degrees C for 24 h followed by 24 h in 5% sodium bicarbonate, with appropriate rinsing between solutions. Paraffin sections of these tissues were stained with a lipid-soluble dye such as Oil Red O. Examples of fat embolism, fatty liver, and atheroma were shown photographically as illustrations of expected results. The demonstration of fat embolism with good quality tissue detail is made practical by the method, which is convenient and inexpensive. The method appears to be generally applicable to tissue lipids of various sorts, as exemplified by adipose tissue, fatty liver, and atheroma.