Graft undergoing necrosis. Immunosuppressed rats were transplanted with viable hCNS-SCns into the right striatum and dead hCNS-SCns (three freeze–thaw passages) into the left striatum. Early loss of MR signal and graft volume indicates graft/cell death. (A–C) MRI showing a left sided intrastriatal graft of killed cells at days 2 (A), 7 (B), and 35 (C) after transplantation. Loss of graft signal and reduction in graft size is noted on the left side, whereas the right side remains unchanged. (D–F) Confocal immunofluorescence image (D), showing number and morphology of Iba-1-positive cells (green) in close relation to hCNS-SCns (red) in a viable graft. In the dead graft (E), morphologically activated Iba-1-positive cells (green) are more abundant and have phagocytosed hCNS-SCns (red) at 35 days after transplantation. (F) Iba-1 expression in healthy brain tissue (insert at higher magnification). Nuclei counterstained with DAPI (blue). (G) Volumes of dead grafts (filled bar) and viable grafts (open bar) based on MR images at 2, 7, and 35 days after transplantation clearly demonstrates the early volume loss (∗, P < 0.05). (H) quantification of Iba-1-positive cell density surrounding the dying grafts (DG), viable grafts (VG), and in normal parenchyma (NP) at 35 days after transplantation. Results are means ± SEM.