TLR4-/- mice displayed attenuations in the neurological deficit and cell death. (A) A coronal brain slice showing an obvious cavity (marked by an asterisk) in the injured cortex. The tissue examined in the experiment is marked by a box. (B) Time-dependent protein expression of TLR4 in the injured tissue. (C) The neurological deficit score of TLR4-/- mice was significantly lower than that of wild-type (WT) mice at 24 hours post-trauma. (D) Representative TUNEL-stained and 4',6-diamidino-2-phenylindole (DAPI)-stained brain sections at 24 hours post-trauma. (E) Representative Fluoro-Jade B (FJB-stained) brain sections at 24 hours post-trauma. (F) Quantification analysis indicated that TLR4-/- mice had significantly fewer TUNEL-positive cells in the pericontusional tissue than WT mice post-trauma. The percentage of TUNEL-positive cells is expressed as the number of TUNEL-stained nuclei divided by the total number of DAPI-stained nuclei. (G) Quantification showed that TLR4-/- mice had significantly fewer degenerating neurons than WT mice in the pericontusional tissue. The total number of FJB-positive cells is expressed as the mean number per field of view. Values (mean ± SD) are representative of three independent experiments (n = 3 *P < 0.05, **P < 0.01. Bar = 20 μm.