Histological, Immunocytochemical, and Morphometrical Analyses of Pancreatic Islets in the BSB Mouse Model of Obesity

Abstract

This article presents biochemical data on the BSB mouse model of multigenic obesity indicating increased percentage body fat, increased fasting plasma insulin, and increased insulin resistance in male and female obese mice compared with lean controls. Plasma glucose was significantly increased only in male obese mice. Morphological and morphometrical analyses of pancreatic islets showed increased islet size and number in all obese mice compared with lean controls. Immuno-staining results for insulin-positive islet cells showed greater levels of insulin in male and female obese versus lean mice, while the percent or proportion of insulin immuno-staining, as expected, was not significantly different between obese and lean. The percent or proportion of immuno-staining for islet glucagon and somatostatin showed reduced staining in islets from obese compared with lean mice. The significance of these findings shows, for the first time, the morphologic appearance of pancreatic islets and the quantitative distribution of the three major islet cell hormonal populations in BSB obese mice. The correlation between this descriptive information and physiological data might lend insights to the cause of obesity-related diabetes.