Alterations in rat pancreatic islet beta cells induced by Keshan disease pathogenic factors: protective action of selenium and vitamin E.

Keshan disease (KD) is an endemic cardiomyopathy occurring in certain areas of China. A combined deficiency of selenium (Se) and vitamin E (VE) has been implicated in the development of KD. In this study, morphological and functional alterations in the islet beta cells of rats fed grain from an endemic area with KD were investigated. Serum insulin levels and glutathione peroxidase (GSH-Px) activity were markedly lower in rats on the experimental diet compared with controls. In pancreatic islet beta cells of rats on the experimental diet, a vacuolation of the Golgi apparatus, slight dilation of the endoplasmic reticulum, and decrease in the number of secretory granules were seen. Supplementation of either 100 mg/kg VE (alpha-tocopherol) and/or 0.1 mg/kg Se (as 0.22 mg/kg sodium selenite) to the experimental diet prevented these islet beta-cell alterations and returned serum insulin to normal levels. Our results demonstrate that the pathogenic factors of KD can induce alterations in islet beta cells, and Se and VE provide protective effects against these pathogenic factors.