Systemic administration of erythropoietin inhibits retinopathy in RCS rats

Weiyong Shen; Sook H Chung; Mohammad R Irhimeh; Shiying Li; So-Ra Lee; Mark C Gillies

doi:10.1371/journal.pone.0104759

Systemic administration of erythropoietin inhibits retinopathy in RCS rats

PLoS One. 2014 Aug 13;9(8):e104759. doi: 10.1371/journal.pone.0104759. eCollection 2014.

Authors

Weiyong Shen¹, Sook H Chung¹, Mohammad R Irhimeh¹, Shiying Li², So-Ra Lee¹, Mark C Gillies¹

Affiliations

¹ Save Sight Institute, the University of Sydney, Sydney, Australia.
² Save Sight Institute, the University of Sydney, Sydney, Australia; Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, China.

Abstract

Objective: Royal College of Surgeons (RCS) rats develop vasculopathy as photoreceptors degenerate. The aim of this study was to examine the effect of erythropoietin (EPO) on retinopathy in RCS rats.

Methods: Fluorescein angiography was used to monitor retinal vascular changes over time. Changes in retinal glia and vasculature were studied by immunostaining. To study the effects of EPO on retinal pathology, EPO (5000 IU/kg) was injected intraperitoneally in 14 week old normal and RCS rats twice a week for 4 weeks. Changes in the retinal vasculature, glia and microglia, photoreceptor apoptosis, differential expression of p75 neurotrophin receptor (p75NTR), pro-neurotrophin 3 (pro-NT3), tumour necrosis factor-α (TNFα), pigment epithelium derived factor (PEDF) and vascular endothelial growth factor-A (VEGF-A), the production of CD34(+) cells and mobilization of CD34(+)/VEGF-R2(+) cells as well as recruitment of CD34(+) cells into the retina were examined after EPO treatment.

Results: RCS rats developed progressive capillary dropout and subretinal neovascularization which were accompanied by retinal gliosis. Systemic administration of EPO stabilized the retinal vasculature and inhibited the development of focal vascular lesions. Further studies showed that EPO modulated retinal gliosis, attenuated photoreceptor apoptosis and p75NTR and pro-NT3 upregulation, promoted the infiltration of ramified microglia and stimulated VEGF-A expression but had little effect on TNFα and PEDF expression. EPO stimulated the production of red and white blood cells and CD34(+) cells along with effective mobilization of CD34(+)/VEGF-R2(+) cells. Immunofluorescence study demonstrated that EPO enhanced the recruitment of CD34+ cells into the retina.

Conclusions: Our results suggest that EPO has therapeutic potentials in treatment of neuronal and vascular pathology in retinal disease. The protective effects of EPO on photoreceptors and the retinal vasculature may involve multiple mechanisms including regulation of retinal glia and microglia, inhibition of p75NTR-pro-NT3 signaling together with stimulation of production and mobilization of bone marrow derived cells.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Apoptosis / drug effects
Blotting, Western
Diabetic Retinopathy / prevention & control*
Erythropoietin / administration & dosage
Erythropoietin / pharmacology*
Flow Cytometry
Fluorescein Angiography
Fluorescent Antibody Technique
Image Processing, Computer-Assisted
In Situ Nick-End Labeling
Neuroglia / drug effects
Rats
Rats, Mutant Strains
Receptor, Nerve Growth Factor / metabolism
Retina / cytology*
Retina / drug effects
Retinal Vessels / drug effects*
Tumor Necrosis Factor-alpha / metabolism

Substances

Receptor, Nerve Growth Factor
Tumor Necrosis Factor-alpha
Erythropoietin

Grants and funding

This study was supported by grants from National Health and Medical Research Council (632839) and Ophthalmic Research Institute of Australia. Mark Gillies is a fellow of Sydney Medical School Foundation and supported by a National Health and Medical Research Council (Australia) Practitioner Fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.