Abstract
Purpose: :
Olfactory ensheathing cells (OECs) are a unique type of glial cells. In situ they ensheath olfactory receptor axons from the nasal mucosa to the olfactory bulb, maintaining open channels for these continuously regenerating neurons. When transplanted into experimental spinal cord lesions OECs maintain their ensheathing and neurotrophic properties and enable axonal regrowth across glial scars. A previous study demonstrated that OECs delivered via a posterior transscleral and transretinal approach migrate towards the ONH and integrate into all retinal layers. The aim of the present study is to explore whether OECs injected intravitreally via an anterior approach more suitable for future translation to humans also follow the nerve fibre layer and potentially integrate into other retinal layers.
Methods: :
We isolated and cultured OECs from Brown Norway (BN) rats. We verified the presence of OEC characteristics by immunocytochemistry (ICC) and RT-PCR. Following staining with cell tracker dye CMFDA-SE we injected 20,000 cells into the vitreous of 4 adult BN rats via an anterior approach, 2mm posterior to the limbus. We perfusion-fixed the animals 3 weeks later and used immunohistochemical stains to visualise retina, optic nerve head and transplanted cells.
Results: :
ICC demonstrated the presence of the low affinity neurotrophin receptor, p75, on all cells in culture. In histological sections of eyes after transplantation OECs covered the nerve fibre layer, without signs of inflammation or rejection.
Conclusions: :
Olfactory ensheathing cells survive transplantation into the eye without host immunosuppression and associate with retinal ganglion cell axons. They may exert beneficial neurotrophic effects which will be the subject of further study by our group.
Keywords: cell survival • retina • neuroprotection