Influence of Glutathione on the Electroretinogram in Diabetic and Non-diabetic Rats

Abstract

Aims: The purpose of this study was to investigate the influence of glutathione on the electroretinogram (ERG) in diabetic and non-diabetic rats.Materials and Methods: Streptozotocin (STZ: 60 mg/kg) was injected into male RCC Wistar rats to induce hyperglycemia, with buffer instead of STZ injected into age-matched non-diabetic controls. After 8 weeks, ERG measurements were obtained at seven different scotopic flash intensities on the two groups of anesthetized, dark-adapted rats (controls, STZ). Following ERG measurements, eyes were enucleated for measurements of retinal/vitreous GSH and glutathione disulfide (GSSG).Results: Diabetic rats produced delayed b-wave ERG signals (increased implicit times), but had normal a-wave and b-wave amplitudes, a-wave implicit times, and oscillatory potentials. No differences were observed in retinal GSH or GSSG between controls and diabetics; however, correlations between GSH and all ERG parameters (with the exception of b-wave implicit times) were noted, and were not significantly altered by the presence of hyperglycemia.Conclusions: GSH is likely to play an important role in retinal function as assessed by the ERG, with this role not substantially altered in rats diabetic for 8 weeks.