Effect of genistein on the pancreas of streptozotocin-induced diabetic male rats: light and electron microscopic study

ABSTRACT

Diabetes mellitus is a worldwide serious health problem. The critical need for novel therapeutic approaches to treat diabetes mellitus is clear. Genistein, a natural soy isoflavone, have numerous health benefits attributed to multiple biological functions. To investigate the effect of genistein on the structure of pancreatic beta cells and acinar cells in streptozotocin-induced diabetic rats. Thirty adult male albino rats were classified into group I [control], group II in which diabetes was induced by a single intraperitoneal injection of streptozotocin [STZ] [80 mg/kg] and group 111 in which the diabetic rats were injected subcutaneously with genistein [0.25 mg/kg/day] Alter 3 months, blood glucose concentrations were assessed and pancreas specimens were processed lor light and electron microscopic study. Immunohistochemical insulin reactivity and morphometric analysis of the islet diameter were also studied. STZ, in group II rats, caused shrinkage of the pancreatic islet and induced beta cell damage in addition to weak insulin immunoreactivity and elevated blood glucose level. Many Icinar cells of this group showed accumulated zymogen granules, pleomorphic mitochondria and small lipid droplets. Genistein, in group III rats, preserved beta cell mass as evidenced by the large islets with strong insulin immunoreactivity and the significant reduction in blood glucose level. Ultrastructurally, beta cells of group III rats had numerous secretory granules and well developed Golgi bodies. Iknvever, the acinar cells of genistein treated rats exhibited more structural changes than group II with loss of the normal polarity and marked damage of mitochondria. Zymogen granules exhibited low electron density with frequent docking to the lateral plasma membrane and granule-granule fusion. Genistein protected the beta cells against STZ-induced damage. However its deleterious effect on the pancreatic acinar cells might limit its benefit as a promising therapy for diabetes mellitus