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Catalase and glutathione reductase co‐localize with insulin in pancreatic beta cells of normal and diabetic rats
Author(s) -
Adeghate Ernest,
Al Darmaki Reem,
Baniyas May,
D'Souza Crystal,
Lotfy Mohamed,
Tariq Saeed
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.511.5
Subject(s) - medicine , endocrinology , insulin , streptozotocin , glucagon , pancreas , immunoelectron microscopy , diabetes mellitus , pancreatic polypeptide , somatostatin , pancreatic islets , immunogold labelling , chemistry , glutathione reductase , oxidative stress , islet , biology , glutathione peroxidase , catalase , antibody , immunohistochemistry , immunology
Background Long‐term diabetes mellitus (DM) is associated with hyperglycemia. Hyperglycemia causes oxidative stress which may subsequently reduce the level of endogenous antioxidants. Hyperglycemia‐induced tissue stress has been implicated in the formation of advanced glycated end products and other factors responsible for the development of short and long‐term complications of DM. Aims Our study aims to determine whether catalase (CAT)‐ and glutathione reductase (GR) are present in pancreatic islet cells and if yes, which of the islet cells contain CAT and or GR? Methods DM was induced in adult male Wistar rats with streptozotocin (60 mg/kg body wt., intraperitoneal). Four weeks after the induction of DM, the rats were anesthetized and part of the pancreas was removed, incubated overnight in Zamboni's fixative and processed for double‐labelled immunofluorescence using antibodies against insulin, glucagon, somatostatin, pancreatic polypeptide, CAT and GR. A portion of the fresh pancreatic was also processed for immunoelectron microscopy using different gold particle sizes as probes for either pancreatic hormone or antioxidant. Results The number of insulin‐, CAT‐ and GR‐immunoreactive cells was significantly (p < 0.05) reduced after the onset of DM. In contrast, the percentage distribution of glucagon‐, somatostatin‐, and pancreatic polypeptide‐positive cells increased in pancreatic islets of diabetic rats, when compared to non‐diabetic controls. CAT and GR were observed in insulin‐containing pancreatic beta cells. A decrease in the number of insulin‐secreting cells was associated with a concomitant reduction in either CAT or GR. Immunoelectron microscopy showed that CAT‐ and GR‐labelled immunogold particles are present in association with insulin in secretory granules of pancreatic beta cell. The number of insulin‐, CAT‐ and GR‐coated gold particles was markedly (p < 0.05) reduced in pancreatic beta cells of diabetic rats. Conclusion Co‐localization of CAT and GR with insulin suggests that these antioxidants may play role in the maintenance of pancreatic beta cell structure and function. Support or Funding Information Supported by research grants from the CMHS (Grant # NP‐14‐32) NP and UAEU (Grant # ZCHS‐7‐2014) This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .