Fold changes of TLRs after TBI and treatment with PROG. The figure shows the fold changes of Toll-like receptors (TLRs) after traumatic brain injury (TBI) compared with the sham group. In the 10 detected TLRs, compared to sham controls, TLR1 and TLR2 genes were significantly up-regulated (A, B). The TLR4 gene was up-regulated 1.9-fold (C). Progesterone (PROG) did not inhibit the increased TLRs, but significantly up-regulated the expression of TLR9 in mice with and without TBI (D). Note: a: compared with Sham; b: compared with Sham+P; d: compared with TBI; ≥2-fold, p < 0.05; Sham: n = 3; Sham+P: n = 3; TBI: n = 5; TBI+P: n = 3.