Abstract
Abstract: :
Purpose: Nestin, an intermediate filament, is an established marker of neural progenitor cells. We investigated changes in nestin expression in the retina during postnatal development and after EGF (epidermal growth factor) treatment in the adult. Methods: Transgenic mice expressing GFP (green fluorescent protein) under the control of regulatory regions of the nestin gene were used for the studies. The mice were sacrificed on P (postnatal day) 0, 2, 4, 8, 15, 28, and 42, and the eyes were histologically examined, including immunohistochemistry for nestin and vimentin. In addition, EGF in Hank's balanced solution (100ng x 2 with a interval of 5 days) or control solution was injected into eyes of the mice at 6 weeks of age. These eyes were also examined histologically. Results: At P 0, intense GFP expression was observed in many cells of the immature retina. Most of the cells showed radial glia-like morphology with radially oriented long processes that extended from the inner surface to the outer surface of the retina. The GFP expression gradually decreased over time, and largely disappeared by day 42. The GFP positive cells began to show Müller cell-like morphology, and became positive for vimentin (a marker for Müller cells) after P5-8. In adult mice that received EGF treatment, strong GFP expression was observed in subpopulation of Müller cells. GFP positive cells were stained by immunohistochemistry for nestin. GFP expression was a better marker than nestin immunohistochemistry, as GFP filled the entire cell body of nestin expressing cells, while nestin staining was confined to discrete regions of these cells. Conclusion: Nestin-GFP mice are useful for examining nestin expression in the developing retina. During postnatal development, nestin appeared to be expressed mostly in precursors of Müller cells. In the adult, nestin was upregulated in the Müller cells by EGF treatment.
Keywords: 479 Muller cells • 564 retinal development • 606 transgenics/knock-outs