Purchase this article with an account.
HoanVu Nguyen, David Williams, Jesse Schallek; Density and distribution of NG2+ pericytes in the living mouse retina. Invest. Ophthalmol. Vis. Sci. 2013;54(15):4878.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Understanding the role of retinal pericytes in health and disease has been limited to ex vivo investigation because pericytes are small and provide poor optical contrast with conventional fundoscopy. Here, we image mice expressing fluorescent pericytes using fluorescence adaptive optics scanning laser ophthalmoscopy (FAOSLO) to characterize the distribution and morphology of retinal pericytes in the living animal.
Mice hemizygous for the NG2 DsRed transgene (Jackson Labs) were imaged with a FAOSLO at two wavebands simultaneously. A reflectance channel recorded blood flow and vascular anatomy with 789nm light. A second channel imaged DsRed fluorescence in pericytes (514 nm exitation, 579+-22 nm emission). Pericyte topography relative to the optic disc was quantified in vivo and confirmed with ex vivo histology of retinal flat mounts.
1) Images of NG2+ cells in the living retina show classic features of pericytes that have been described ex vivo, including banded morphology on arterioles and stellate morphology on venules, with both often clustered at branching points. Fluorescence pervaded soma and dendritiform processes in pericytes that ensheath capillaries. Axial sectioning in vivo was sufficient to reveal labeled cells at each of three capillary stratifications in the mouse retina. Strong fluorescence was seen at all ages imaged from 1.5 months-1.65 years. 2) Ex vivo counts corroborated in vivo counts with estimated densities not significantly different with the two methods. NG2+ cells were densely packed on arterioles and venules and with sparse distribution on capillaries. 3) Capillary pericytes were relatively uniform in density across the retina, 669+-309 cells/mm2, (+- 1SD, N=3). Peak density was at 0.6 mm from the optic disc and waning density with greater eccentricity. The ratio of the pericytes to retinal neurons was constant across the retina. For example, the ratio of ganglion cells to pericytes was 10-15:1.
We provide the first characterization and density measures of retinal pericytes in the NG2 DsRed transgenic mouse. High resolution fluorescence imaging and histology has revealed the subcellular structure of individual pericytes as well as the first estimates of their topography in the living eye. Together, these data provide the foundation for studies that measure changing pericyte structure and density in mouse models of vascular disease such as diabetic retinopathy.
This PDF is available to Subscribers Only