September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
Distribution of γ-glutamyltranspeptidase, aldose reductase, and biomarkers of oxidative stress in STZ-induced diabetic rat lens.
Author Affiliations & Notes
  • Marlyn P Langford
    Ophthalmology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States
  • Randa Eshaq
    Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States
  • Thomas B Redens
    Ophthalmology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States
  • Norman R Harris
    Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, United States
  • Footnotes
    Commercial Relationships   Marlyn Langford, None; Randa Eshaq, None; Thomas Redens, None; Norman Harris, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 2506. doi:
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      Marlyn P Langford, Randa Eshaq, Thomas B Redens, Norman R Harris; Distribution of γ-glutamyltranspeptidase, aldose reductase, and biomarkers of oxidative stress in STZ-induced diabetic rat lens.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2506.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : To investigate gamma-glutamyl transpeptidase (GGT, key to glutathione recapture and cell transformation), aldose reductase (AR, converts excess glucose to sorbitol) and oxidative stress markers, [8-OHdG (8-hydroxy-2’-deoxyguanosine, oxidized DNA marker) and annexin V (indicative of apoptosis)] expression in streptozotocin (STZ)-induced diabetic cataractous and normal rat lens.

Methods : Gross ocular examinations were performed and blood glucose levels were determined on adult control and diabetic [STZ-injected] Wistar rats. Bilateral eye enucleations were performed post euthanasia at 8 weeks and the eyes placed in 70% ethanol. Gross histopathology was determined on paraffin-embedded sections stained with hematoxylin and eosin. DAPI-treated sections were reacted with antibody to AR, GGT, 8-OHdG, and/or annexin V, the corneal and lens distributions were visualized using the immunofluorescent antibody method, and digital images captured for comparative analysis.

Results : Gross cytopathological changes consistent with lens epithelial cells disorganization and sub-capsular lens fiber cell hyperplasia were noted in the cataractous lens of hyperglycemic STZ-injected rats. In control rat lens, GGT was prominently expressed by epithelial cells and diminished to undetectable levels within 1 mm (cortical zone) of the lens surface. GGT was not detected in the lens core of control rat lens. AR and oxidized DNA (8-OHdG) were detected in normal lens beneath the lens cortex within the lens fibers (1 mm from the surface) and core. Weak annexin V reactivity was detected in the lens epithelium. In the diabetic rat lens, GGT expression in epithelial cells was decreased, while GGT expression was increased on sub-capsular hyperplastic lens fiber cells. GGT was not detected in the diabetic lens nucleus. Increased AR expression and oxidized DNA (8-OHdG) were detected in the sub-capsular hyperplastic lens fiber cells of diabetic rat lens. Oxidized DNA was detected in annexin V-positive lens epithelial cells of some diabetic lenses.

Conclusions : The sub-capsular cataractogenic changes in STZ-induced hyperglycemic diabetic rats were associated with increased expression of AR and GGT with oxidized DNA-positive hyperplastic lens fiber cells. The results support hyperglycemia-induced lens fiber cell dedifferentiation and oxidative epithelial cell death as evidenced by annexin V expression.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

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