Purchase this article with an account.
L. Wu, S. Park, J. Cao, S. Chang, M. Forbes, J. C. Tsai; Exogenous Erythropoietin Increased Retinal Superficial Vascular Density in Episcleral Venous Ligation Model of Aging Rats. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5683.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
(1) To evaluate the morphology and density of retinal microvascular networks in young (3 months) and aged (11 months) rats. (2) To evaluate the effects of a single intravitreal injection of erythropoietin (EPO, 200ng) on retinal microvascular networks in aged rat eyes with transient ocular hypertension produced by Episcleral Venous Ligation (EVL).
Twenty-six retinas of normal young (n=6), normal aged (n=6), EVL aged (n=8) and EVL+EPO (n=6) aged rat eyes stained by transcardiac perfusion of Rhodamine ConA-lectin were prepared as whole flatmounts. A total of 269 images in the normal young and aged rats, and 265 images in the EVL and EVL+EPO rats were evaluated by Axioplan II fluorescence microscopy utilizing automated computer-assisted imaging analysis software (AxiaVison 4.3). The density of retinal microvascular networks was expressed as the percentage of the stained area. Two-way ANOVA was performed.P-values less than 0.05 were considered statistically significant.
(1) In the retina of young normal rats, a fine meshwork appearance was observed in the superficial and deep retinal vascular networks. In contrast, the normal aged retina displayed vascular degenerative changes including rigid and tortuous capillaries, microaneurysms, and non-perfused capillaries, especially in the deep capillary network. Based on quantitative analysis, there was no significant difference in the superficial vascular density between young and aged rats (16.41 % vs. 14.07%, p>0.05), but there was a significant decrease in the density of the deep retinal capillaries in aged rats compared to young rats (10.78% vs. 22.03%, P <0.001). (2) The total retinal vascular density in aged EVL-EPO eyes was significantly higher than that in aged EVL eyes (31.39 % vs. 25.93 %, p<0.05). (3) There was no difference in the retinal superficial vascular density between aged EVL eyes and normal aged eyes (16.66 % vs.14.07%, p>0.05). However, there was a very significant increase in the superficial retinal vascular density in aged EVL-EPO eyes compared to normal aged eyes (23.23% vs.14.07%, p<0.01).
In aged rats, the deep retinal capillary networks appear vulnerable to degeneration (compared to young rats) whereas no such degeneration was observed in the superficial retinal vasculature. In the aged EVL rat retina, exogenous erythropoietin appears to increase superficial retinal vascular density, but has no significant effect on the degenerated deep capillary vasculature.
This PDF is available to Subscribers Only