Purpose
To compare the long term transplantation of acutely purified retinal ganglion cells (RGCs) onto normal and optic nerve crushed retina both ex vivo and in vivo.
Methods
Optic nerve crush was performed on Sprague-Dawley rats. RGCs from postnatal 4 (P4) transgenic β-actin-GFP mice were acutely purified by sequential immunopanning, transplanted onto retina explants at different time points and co-cultured for 7days. Also, RGCs were injected intravitreally and animals survived for 28 days. After immunostaining, transplanted RGC survival was quantified by nuclear morphology. Migration into the ganglion cell layer was quantified with 3D Z-stack projections using confocal fluorescence microscopy.
Results
Ex vivo transplanted RGCs to the 21, 30, and 41 days-post-axotomy damaged retina survived, migrated, and extended neurites more than controls or 14 days-post axotomy, at increasing times after optic nerve crush. The transplanted RGCs gave much more neurites and migrated deep into the retina, and also we found more cells clustered. In vivo, more cells survived in the 30 day-post axotomy eyes. About 35% of transplanted RGCs migrated under the ganglion cell layer or even into inner nuclear, compared to about 6% in normal eyes. In the inner retinal layers, donor RGCs demonstrated typical RGC morphology, extending long axons and short dendrites, in the previously axotomized but rarely in normal eyes.
Conclusions
After optic nerve injury, transplanted purified RGCs can survive and migrate better both ex vivo and in vivo compared to transplant into normal eyes. Ex vivo, donor cells elaborate more neurites in shorter times, whereas in vivo, cells migrate deeper and demonstrate more typical neurite morphology.
Keywords: 531 ganglion cells •
741 transplantation •
494 degenerations/dystrophies