Abstract
Abstract: :
Purpose:Pericytes play important roles in maintaining the normal function of retinal vasculature. NG2, a membrane bound proteoglycan, was shown to be expressed in mural cells during vascular morphogenesis. We have examined the use of NG2 as a marker for pericytes in developing and mature retinal vasculature. Methods:Retinas from mice of different age (from postnatal day 2 to adult) as well as those treated with 75% oxygen for 5 days and then recovered in room air for 5 days were stained with anti-NG2, isolectin-IB4 and anti-GFAP. The identity of NG2 positive cells in retinal vasculature was further determined with elastase-digested retina preparations. Samples were examined with conventional microscopy and confocal microscopy. Results:The NG2 positive cells appear early in developing retina. The staining is primarily associated with vasculature. In adult retinal vasculature, some NG2 positive cells displayed a distinct «bulging» shape, which is typical of pericytes. The identity of these cells is further confirmed in elastase digested retinal preparation. In oxygen-induced neovascularization, new vessels are strongly stained with NG2 but bulging staining pattern is absent. Conclusion: In adult mice, the retinal pericytes can easily be identified by NG2 antibody showing a characteristic bulging shape. Anti-NG2 also stains new capillaries induced by hypoxia condition or of developing retina. The possibility of proliferating endothelial cells expressing NG2 will be discussed.
Keywords: 614 vascular cells • 554 retina • 474 microscopy: light/fluorescence/immunohistochemistry