Purpose:
The use of lasers is becoming increasingly widespread. Accordingly, a growing number of occupational eye accidents involve laser injuries, which are at present untreatable and the photoreceptor loss irreversible. Here we investigate the integration, differentiation and connectivity of murine GFP-positive RPCs transplanted into the subretinal space of mice with laser-induced damage to the outer retina.
Methods:
RPCs harvested from the neural retinas of postnatal day 1 enhanced GFP mice were grown in neurobasal medium supplemented with epidermal growth factor (20ng/ml). Photocoagulation was performed using a diode laser. Two µl of GFP donor cell suspension, containing ~2 x 105 cells, were injected into the subretinal space. Mice were sacrificed 2 to 6 weeks after transplantation. Immunohistochemistry study was performed with the following primary antibodies GFP, rhodopsin, recoverin, bassoon, peripherin-2, rom-1, protein kinase C (PKCα), mGluR-8, mGluR-6, GFAP. Retinal sections were viewed on a confocal microscope. Cell morphometry was performed to assess the integration of donor cells.
Results:
Two to six weeks after transplantation, substantial numbers of cells had migrated and incorporated into the recipient neural retina(Figure). Most of these integrated cells were correctly oriented within ONL around the retinal laser lesion, and had developed morphological features typical of mature photoreceptors. Some of the integrated cells in the ONL were double-labeled with GFP and photoreceptor-associated markers, including rhodopsin, recoverin, peripherin-2, and rom-1. Some of the integrated cells expressed the ribbon synapse protein bassoon, and made synaptic contact with rod bipolar cells, identified by immunostaining with PKC.
Conclusions:
Transplanted cells migrate and integrate into ONL of the retina with laser injury, differentiate into photoreceptors, and seem to form synaptic connections. This study suggests that cell replacement therapy may be used as a treatment for retinal laser injury.
Keywords: transplantation • retina • regeneration