Anti-LPA mAb (B3) is neuroprotective by reducing apoptotic neuronal death after SCI. One week after SCI, apoptotic cells were observed at the lesion site in isotype-treated control mice (A and B; box enlargement) compared with reduced TUNEL staining in B3 treatment (C and D; box enlargement). E–G: Colabeling of TUNEL staining with the neuronal marker NeuN shows apoptotic neurons (arrowheads). Immunostaining for active caspase-3 increased in control (H) compared with B3 (I) treatment and colocalized with NeuN (J–L). M: Quantitation of number of neuronal cells at the lesion site and 5 mm proximal (upstream of the lesion site) reveals that in B3 treatment, the number of neuronal cells at the lesion site was significantly higher than in controls. Results are the mean ± SEM of NeuN-positive cells in the field (n = 7 in each group). *P < 0.001 by two-tailed t-test, 95% confidence). Scale bars: 100 μm (A, B, H, and I); 50 μm (C–G and J–L).