A new procedure for multiple intraretinal transplantation into mammalian eyes

A new method of intraretinal grafting is described which avoids opening the globe and allows direct visual control of the transplant by observing placement of the graft through the host pupil. A microsyringe with a bevelled needle partially ensheathed in plastic tubing in order to limit penetration was used to inject dissociated donor cells into 2 to 4 pre-selected points of the sub-retinal space of adult rats. The needle tip was inserted through the scleral and choroidal tissue, and observed through the animal's pupil as it reached into the sub-retinal space. Donor cells were then injected into several sites of the retina. Results, using ophthalmoscopy as well as light and electron microscopy, confirmed the atraumatic nature of this technique and the survival of grafted cells. Intraretinal injection of colloidal carbon visually illustrated the effectiveness of this method in covering an extended portion of the host retina. The procedure, which is virtually free of complications has enabled us to perform multisite intra-ocular grafting in a safe, easy, and reliable fashion, under direct visual control.