Cerebral alloreactive T-cell infiltration leads to cell damage and cognitive deficits. (A) Histopathological CNS findings in syngeneic and allogeneic transplanted animals. Lethal GVHD (0.5 × 106 T cells) assessed at day 21 (Allo1 ) or nonlethal GVHD (0.25 × 106 T cells) assessed at days 42 (Allo2 ) and 63 (Allo3 ). Control groups received equal number of syngeneic T cells. GVHD score (0 within normal limits, ≥ 1 pathology) and estimated infiltration with lymphocytes (0 none/rare, 1 mild, 2 moderate, 3 marked, 4 severe) using immunohistochemistry for CD3. (B) Terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick end labeling staining in representative coronal brain sections 21 days after allo-HSCT in cerebellum gray matter (1, 2, 4), cortex (3), corpus callosum (5), hypothalamus (6), and hippocampus (7). (C) Wet brain weights after allo- and syn-HSCT (n = 13-14). (D) Accelerated Rotorod test measuring motor coordination by latency to fall. (E) Grip test measuring strength and neuromuscular function where latency to fall was measured. (F) Exploratory activity and anxiety was measured in an open field test where distance moved in center squares was measured. (G-H) Spatial memory and learning were assessed in the gold standard Morris water maze. (G) Time spent finding the platform over 5 consecutive days or (H) time spent in each quadrant were measured. (I) Motor function and mobility were assessed by measuring the total distance moved in the open field test. (J) Mobility was measured by examining the velocity in the Morris water maze. *Represents a comparison between syn-HSCT and allo=HSCT; ^Represents a comparison between untreated and allo-HSCT. For all behavioral tests, n = 20/treatment group. Bar graphs represent mean ± standard error of the mean of at least 2 independent experiments. *P < .05; **P < .01, ***P < .001.
