Alterations of Tyrosine Hydroxylase and Choline Acetyltransferase in the Retina of the Diabetic Rat / 대한해부학회지

ABSTRACT

To investigate the effect of hyperglycemia on the visual system, we investigated the retinal dopaminergic and cholinergic systems using tyrosine hydroxylase (TH) and choline acetyltransferase (ChAT) in the rat retinas of streptozotocin (STZ)-induced diabetes. Diabetes was induced by a single intraperitoneal injection of STZ (50 mg/kg) to Sprague-Dawley rats (250~300 g). We first analyzed morphologic thickness changes in the several retinal layers of 6-week-old control and STZ-diabetic rats after H & E staining. To confirm whether TH and ChAT protein expressions changed, we carried out immunohistochemistry analysis and Western blotting. After induction of diabetes, significant changes were not shown in the retinal thickness at 6 weeks. TH and ChAT immunoreactivities were clearly detected in amacrine cells and sublaminas in the inner retina of both control and diabetic rats, showing continuously reduced positive amacrine cells in the retinas during diabetes. In addition, the decline in TH and ChAT protein expression was already present to a significant extent in the retina at 6 weeks in early diabetes. Our present study demonstrates the possibility that the observed alterations in TH and ChAT in the diabetic retina may cause the visual system changes in the retinal pathophysiology associated with diabetes mellitus.