Epididymal fat pad alterations in mice with spontaneous obesity and diabetes and with chemically induced obesity

Abstract

Pathologic alterations have been found in the epididymal fat pad of five strains of spontaneously obese or diabetic mice and in one strain of normal mice made obese by a single injection of goldthioglucose. - Histologic abnormalities were observed in the epididymal fat pad of all obese and diabetic mice. These abnormalities were at first characterized by a remarkable growth of the individual fat cell. Later, coinciding with a weight loss of the pad, and in some instances discoloration, the pad became hypercellular. A variable number of macrophages, mast cells and fibroblasts were observed occupying the intercellular spaces and a few fat cells appeared to be diminishing in size. - Overt necrosis and foci of acute inflammatory reaction of the epididymal fat pad was only seen in 9 month old T-KK mice. - "Lean" KK mice, having at all times an underdeveloped epididymal fat pad, were free of the lesions mentioned above. - Prediction of the character and degree of the pathologic changes in the early stages could not be made by gross observation of the fat pad. Histologie methods appear to be necessary to ascertain the condition of the epididymal fat pad of mice having abnormal body weight or abnormal plasma insulin levels. © 1974 Springer-Verlag.