A Reliable Photomicrographic Method for Determining Fat Cell Size and Number: Application to dietary obesity

SummaryRat and human isolated adi-pocyte sizes were determined by both the measurement of their diameter on photomicrographs and by electronic counting of osmium-fixed cells. The average cell size was 0.348 and 0.353 μg of lipid/cell, respectively. The agreement between the two methods was excellent over a wide range of cell sizes (0.15-0.09 μg of lipid/cell). The photomicrographic method was applied to a morphological study of epididymal adipose tissue in Wistar rats fed a high-fat diet for either 1 or 10 months. The enlargement of the adipose depot induced by 1 month of the high-fat diet was achieved by an increase of fat cell size only. Ten months of high-fat feeding induced either a moderate obesity with only hypertrophy of the adipocytes or a severe obesity with apparent hyper-trophic-hyperplastic changes.