April 2011
Volume 52, Issue 14
Free
ARVO Annual Meeting Abstract  |   April 2011
Early Visual Acuity Deficits in a Rat Model of Diabetic Retinopathy
Author Affiliations & Notes
  • Moe H. Aung
    Neuroscience/Ophthalmology, Biomedical Laboratory Research and Development,
    Emory University, Atlanta, Georgia
  • Moon K. Kim
    Neuroscience/Ophthalmology, Biomedical Laboratory Research and Development,
    Atlanta VA Medical Center, Decatur, Georgia
  • Darin E. Olson
    Neuroscience/Ophthalmology, Biomedical Laboratory Research and Development,
    Endocrinology, Rehabilitation Research and Development,
    Emory University, Atlanta, Georgia
    Atlanta VA Medical Center, Decatur, Georgia
  • Peter M. Thule
    Neuroscience/Ophthalmology, Biomedical Laboratory Research and Development,
    Endocrinology, Rehabilitation Research and Development,
    Emory University, Atlanta, Georgia
    Atlanta VA Medical Center, Decatur, Georgia
  • Machelle T. Pardue
    Neuroscience/Ophthalmology, Biomedical Laboratory Research and Development,
    Endocrinology, Rehabilitation Research and Development,
    Emory University, Atlanta, Georgia
    Atlanta VA Medical Center, Decatur, Georgia
  • Footnotes
    Commercial Relationships  Moe H. Aung, None; Moon K. Kim, None; Darin E. Olson, None; Peter M. Thule, None; Machelle T. Pardue, None
  • Footnotes
    Support  Research to Prevent Blindness, Department of Veterans Affairs
Investigative Ophthalmology & Visual Science April 2011, Vol.52, 5960. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Moe H. Aung, Moon K. Kim, Darin E. Olson, Peter M. Thule, Machelle T. Pardue; Early Visual Acuity Deficits in a Rat Model of Diabetic Retinopathy. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5960.

      Download citation file:


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

      ×
  • Supplements
Abstract

Purpose: : Vascular abnormalities define clinical diabetic retinopathy (DR). However, studies increasingly suggest that neuronal dysfunction precedes retinal vascular changes. Previously, we reported delays in the scotopic ERG following 4 weeks of hyperglycemia in steptozotocin (STZ) treated rats and mice. Here we assess visual acuity in STZ rats and examine its correlations with cataract formation, retinal dysfunction, and duration of diabetes.

Methods: : Retinal function (monthly dark-adapted ERGs), cataract formation (biweekly slit lamp exam), and visual acuity (weekly optokinetic tracking) was assessed longitudinally for 12 weeks in two groups of pigmented Long-Evans rats: control (n=8) and diabetic (n=8). Diabetes was induced by STZ injection (100 mg/kg, i.v) and confirmed through serially elevated blood glucose (>250 mg/dl). Only responses from the right eye were analyzed and compared between the two groups.

Results: : As early as 5 week post-STZ, diabetic animals exhibited an average 25% decreased visual acuity (Two-way RM ANOVA, p=0.005). Diabetic rats also exhibited significantly higher cataract score (indicating denser cataract formation) compared to controls (p=0.002), starting at 6 week post-STZ. Similar to our previous reports, the latency to a dim flash (0.02 cd sec/m2) of summed oscillatory potentials (OPs) was significantly delayed in diabetic rats compared to controls (p<0.001) as early as 4 week post-STZ. Importantly, the magnitude of all deficits significantly increased with the duration of diabetes (p<0.05). In contrast, both the amplitudes and implicit times of a-wave and b-wave did not consistently differ between control and diabetic animals. While none of the variables examined correlated with visual acuity in control rats, cataract score correlated most strongly with visual acuity changes among diabetic rats (Pearson correlation, r2 = 0.534, p<0.0001).

Conclusions: : Diabetes markedly reduces visual acuity in STZ rat, as early as 5 week post-STZ. Although the visual defects may be related to previously reported retinal neuronal changes in STZ rats, such as inner retinal dysfunction, it is important to note that cataract formation may be another contributing factor to the deficit.

Keywords: diabetic retinopathy • electroretinography: non-clinical • visual acuity 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×