Impaired apparent ion demand in experimental diabetic retinopathy: correction by lipoic Acid - PubMed (original) (raw)

Purpose: To test the hypothesis that early in the course of diabetes, apparent ion demand within the retina is impaired and may be corrected by alpha-lipoic acid (LPA), a drug that inhibits vascular histopathology.

Methods: Intraretinal manganese ion uptake and retinal thickness were measured from high-resolution manganese-enhanced MRI (MEMRI) data of control and streptozocin diabetic male Sprague-Dawley (SD) rats and of control and diabetic female Lewis rats with and without treatment with LPA. In a subgroup of male SD rats, blood-retinal barrier (BRB) integrity was also assessed with dynamic contrast-enhanced MRI. In addition, ion-coupled plasma-mass spectrometry (ICP-MS) was used to measure baseline whole manganese levels from retinas of control and diabetic rats.

Results: Manganese ion uptake by receptor and postreceptor retina was subnormal in each untreated diabetic groups, and these deficiencies could be corrected with LPA treatment. ICP-MS studies found no differences in baseline retinal manganese concentration between control and diabetic rats. In 3-month-old diabetic male SD rats, total and postreceptor retinal thickness increased (P < 0.05) without loss of BRB integrity. In contrast, in untreated and treated diabetic female Lewis rats, retinal thicknesses were normal.

Conclusions: The present results support the hypothesis that LPA can correct the impaired apparent ion demand in experimental diabetic retinopathy.