Abstract
Purpose: :
Bone marrow (BM)-derived myeloid progenitors have been shown to have beneficial effects in retinal degenerative diseases. The majority of these studies have used developmental models including oxygen induced retinopathy and the rd/rd mouse, both of which involve injecting cells while the retina is still maturing. In mice, similar cells do not target the normal, healthy adult eye. However, techniques are required to facilitate targeting and maintenance in adult eyes if they are to be useful for treating ocular vascular disorders such as diabetic retinopathy. We demonstrate that low intensity laser stimulation of the retina can lead to large-scale, rapid targeting of myeloid progenitor cells.
Methods: :
After anesthesia and pupil dilation, retinas of rodents (8-10 week old mice and rats) were treated at the posterior pole adjacent to the optic nerve, taking care not to disrupt the major retinal vessels. Laser spots were created using a green wavelength diode laser (IRIS), with 200 mW power for 0.05 seconds creating spot sizes of ~50 microns. GFP expressing myeloid progenitors, or control populations of non-functional BM-derived cells, were injected intravitreally 4 hours following the laser burns and the retinas analyzed for GFP positive cells.
Results: :
Myeloid progenitor cells target in large numbers to sites of retinal low-grade laser application. These cells assume the typical microglia-like morphology in contrast to control cells that do not target to the retina nor change morphology.
Conclusions: :
Low-grade, non injury levels of laser treatment can be used to stimulate targeting of bone marrow-derived myeloid progenitors to the retina. Such techniques may be useful for targeting cells to the retina for long-term cell therapies designed to treat adult retinal vascular and neuronal degenerative disorders.
Keywords: laser • retinal neovascularization • microglia