TLR4 expression at 24 h after traumatic brain injury (TBI) and the effect of combination of progesterone and vitamin D (VDH) on TLR4 expression. A. Protein expression of TLR4 assessed by western blot. B. Adjusted density of TLR4. n=5, α: p < 0.05 vs. Sham; β: p < 0.05 vs. TBI. C. Immunostaining of TLR4 (indicated by arrows). D. Double-labeling of TLR4/GFAP, TLR4/MAP2, TLR4/CD31, and TLR4/CD68. Scale bar is 20 μm. Sham: sham with vehicle treatment; TBI: TBI with vehicle treatment; TBI+P: TBI with progesterone treatment; TBI+D: TBI with vitamin D treatment; TBI+P+D: TBI with progesterone and VDH combination treatment, n=5.