FIG. 2.

Cross-section through the epicenter of a GFP-FSC transplant, 4 weeks after grafting. Donor tissue has filled the cavity, become confluent with host gray matter and contains mature astrocytes (white) and neurons (red), seen at high power in (C) and (D), respectively. In a different donor recipient, Ki-67 immunohistochemistry reveals a large number of cells still actively dividing at 1 month post-transplant (F–I). Whereas Ki-67–positive cells likely include both neurons and glia, one dividing, PRV-positive neuron (retrogradely labeled from the host phrenic motor pool) is visible (red arrow, I). (J–M) Transplanted tissue is well vascularized, and blood vessels appear to be continuous with those in the host, as seen by RECA immunolabeling (L, white). Scale is 500 um (A), 50 um (B–E), 50 um (F–I), and 500 um (J–M). 5HT, serotonin; FSC, fetal spinal cord; GFAP, glial fibrillary acidic protein; GFP, green fluorescent protein; NeuN, neuronal nuclear protein; PRV, pseudorabies virus; RECA, rat endothelial cell antigen. Color image is available online at www.liebertpub.com/neu