New method of transplanting purified glial cells into the brain

This paper describes a new transplantation method for testing the ability of purified populations of glial cells to support axonal growth in the brains of adult animals. Thin tubes, rolled from porous polycarbonate film, are coated with poly-L-lysine and filled with cultured Schwann cells. Schwann cell-filled tubes or control tubes (poly-L-lysine coated only) are then implanted into the brains of adult rats so that one end of the tube is in the thalamus and the other extends extracranially. After survival times of 4-16 weeks horseradish peroxidase (HRP) is applied to the extracranial end of the tube. One or two days later the animal is perfused and the brain is sectioned and processed histochemically. Results show that tubes containing Schwann cells are densely filled with tissue and are well vascularized. Further, neurons in the central nervous system are retrogradely labeled with HRP and most labeled cells are concentrated in regions of the diencephalon near the end of the tube. Control tubes contain very little tissue and show no evidence that they support axonal growth. These results are consistent with the hypothesis that Schwann cells can support axonal growth in the brains of adult rats.