Evaluation of Müller Cells in Retinal Detachment of the Pig

Abstract

Purpose: : Detachment of the neural retina from the pigment epithelium causes photoreceptor deconstruction, neuronal cell remodeling, and activation of glial cells. It has been suggested that gliosis contributes to the impaired recovery of vision after reattachment surgery that may involve both formerly detached and non–detached retinal areas. To determine whether gliosis is present in detached and non–detached retinal areas, we monitored Müller and microglial cell reactivity in a pig model of rhegmatogenous retinal detachment.

Methods: : Local detachment in pig eyes was created by subretinal application of hyaluronate. Retinal slices were immunostained against various glial proteins. In retinal wholemounts, ATP–induced intracellular Ca²⁺ responses were recorded in Müller cells, and microglial cells were stained. K⁺ currents were recorded in isolated Müller cells.

Results: : At 3 and 7 days after surgery, Müller glial cells showed pronounced gliosis, as revealed by the increased expression of the intermediate filaments glial fibrillary acidic protein and vimentin, by the decrease of Kir4.1 immunoreactivity and of the whole–cell K⁺ currents, and by the increased incidence of cells that showed Ca²⁺ responses to ATP. The increased expression of intermediate filaments, and the increased Ca²⁺ responsiveness, were observed in both detached and non–detached retinal areas. The density of microglial cells at the inner surface of the retinas increased in detached and non–detached areas.

Conclusions: : Reactive responses of Müller and microglial cells are not restricted to detached retinal areas but are also observed in non–detached regions of the pig retina.

Keywords: retinal detachment • Muller cells • microglia