Effects of DHA on astrocyte activation and TNF-α expression in spinal cord tissue. Spinal cord sections were processed 24 h after SCI to determine the immunohistological staining for GFAP and TNF-α expression. Sham animals never express GFAP (A, see densitometry analysis G), the number of GFAP+ cells was significantly increased upon induction of SCI, due to astrocytes proliferation around the central canal (B, see densitometry analysis G).Treatment with DHA significantly decreased the activation of astrocyte-GFAP+ cells (C, see densitometry analysis G).Moreover, no positive staining for TNF-α was found in the spinal cord tissue from sham-operated mice (D, see densitometry analysis H). A substantial increase in TNF-α expression was found in spinal cord tissues from SCI mice 24 h after SCI (E, see densitometry analysis H). DHA treatment significantly attenuated TNF-α levels in the spinal cord (F, see densitometry analysis H). (G,H) Densitometry analysis of immunohistochemistry photographs (n = 5 photos from each sample collected from all mice in each experimental group) for GFAP and TNF-α from spinal cord tissues. The figure is representative of at least three experiments performed on different experimental days. For each SCI group see the high magnification of the images. Data are expressed as percentage of total tissue area. Data are mean ± SEM of ten mice for each group.*P < 0.05 vs. Sham. °P < 0.01 vs. SCI. ND: not detectable.