Exp Clin Endocrinol Diabetes 2010; 118(8): 467-472
DOI: 10.1055/s-0030-1252068
Article

© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

A Protective Effect of Endomorphins on the Oxidative Injury of Islet

L. M. Tian1 , J. Liu1 , X. L. Sun2 , C. X. Gao1 , Y. Fan3 , Q. Guo1
  • 1Department of Endocrinology, People's Hospital of Gansu Province, Lanzhou, PR China
  • 2Department of Endocrinology and Metabolism, Shandong University, Jinan, Shandong, PR China
  • 3Department of Life sciences, Lanzhou University, Lanzhou, PR China
Further Information

Publication History

received 16.03.2010

first decision 16.03.2010 accepted 25.03.2010

Publication Date:
28 April 2010 (online)

Abstract

The antioxidative capacity of endomorphins (EMs), endogenous μ-opioid receptor agonists, has been demonstrated by in vivo assays. In this study, we attempt to evaluate the effects of endomorphin 1 (EM1) and endomorphin 2 (EM2) on pancreatic islet injuries induced by streptozotocin (STZ), alloxan (ALX) and H2O2, respectively. Wistar rats’ islets were isolated and purified. The function of the islet cells, the insulin response to glucose stimulation was examined by insulin Radio Immuno Assay and the cell viability was measured by MTT assay. DNA fragments were performed to evaluate the apoptosis, while the cell cycle distribution was analyzed by PI staining flow cytometric analysis. Furthermore, the islet were treated with EM1, EM2 or ALX for 24 h, and the expression of p53 and p21 protein were determined by Western blot. The results showed that STZ, ALX, and H2O2 displayed clear concentration-dependent inhibitory effects on the pancreatic islet cells. While EMs improved the viability of islet induced by STZ, ALX or H2O2, and EMs enhanced insulin accumulation of the cell supernatant after ALX and STZ stimulation. Our data also showed both that EMs inhibited cell apoptosis and cell cycle G1 arrest induced by STZ and ALX through down-regulaing p53 and p21 expression. Taken together, these results demonstrate that EMs can protect islet cells from STZ, ALX and H2O2 induced injuries. Our observations imply that the endomorphins may have protective effects on islet cells oxidative injury.

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Correspondence

J. Liu

People's Hospital of Gansu Province Endocrinology

Donggang xilu 160

Lanzhou

730000 Lanzhou

China

Email: tlm6666@sina.com