Abstract
Purpose: :
To determine if bestrophin is present in the basal membrane of macular retinal pigment epithelium (RPE) and drusen of elderly monkeys with age related drusenoid maculopathy..
Methods: :
The macular region of the retina of three female rhesus monkeys (Macaca mulatta), 23-24 years of age with drusenoid maculopathy was dissected from eyes fixed with 4% para-formaldehyde. The macula was sectioned into rectangular pieces and the neural retina and sclera removed from each piece. Each segment was incubated with a goat polyclonal antibody to bestrophin, reacted with gold labeled rabbit antibody to goat IgG, silver enhanced and processed for transmission electron microscopy.
Results: :
Bestrophin labeled gold particles were found in quasi-linear arrays on the basal surface of the macular RPE and also within drusen where bestrophin was detected in curled segments of membranous-like material. The array density of the bestrophin linked gold particles gave a minimal value of about 100 bestrophin molecules/mm2 on the basal membrane of the RPE. Immuno-detection of bestrophin was most effective when examined in the RPE layer remaining attached to the neural retina, which exposes the basal surface of the epithelium more directly to the antibodies.
Conclusions: :
Bestrophin remains on the basal membrane of macular RPE of elderly monkeys with age related drusenoid maculopathy but is also found in membranous-like structures in drusen. This supports the hypothesis that segments of the basal membrane of the RPE comprise some of the material within drusen..
Keywords: immunohistochemistry • drusen • retinal pigment epithelium