Figure 6

Immunohistochemical localization of Fas-ligand and TUNEL staining in the spinal cord tissue. Immunohistochemical analysis for Fas-ligand show positive staining localized in the inflammatory cells in the injured area from PPAR-αWT mice (panel A b, g). The intensity of the positive staining for Fas-ligand was markedly increased in tissue section obtained from injured-PPAR-αKO mice (panel A e, g). No positive staining for Fas-ligand was observed in tissue section from simvastatin-treated PPAR-αWT mice (panel A c, g). The genetic absence of the PPAR-α significantly blocked the effect of simvastatin treatment (panel A f, g). To test whether the tissue damage was associated with cell death by apoptosis, we measured TUNEL-like staining in the injured tissue. No apoptotic cells were detected in the spinal cord from sham-PPAR-αWT mice (panel B a, d and g). Tissue sections from PPAR-αWT animals at 24 h after SCI demonstrate a marked appearance of dark brown apoptotic cells (panel B b, g). Tissue sections from PPAR-αKO animals at 24 h after SCI demonstrate a marked appearance of dark brown apoptotic cells (panel B b, g). The genetic absence of the PPAR-α receptor significantly blocked the effect of simvastatin (panel B f, g). Densitometry analysis of immunocytochemistry photographs (n = 5 photos from each sample collected from all mice in each experimental group) for Fas-ligand from spinal cord tissues was assessed. Data are expressed as % of total tissue area. This figure is representative of at least 3 experiments performed on different experimental days. *P < 0.01 vs. Sham; °P < 0.01 vs. SCI-WT group; °°P < 0.01 vs. simvastatin-treated WT group. ND: not detectable.