Interleukin-6 and keratinocyte-derived chemokine concentrations in brain homogenates. Concentrations of IL-6 and KC were measured in brain homogenates and normalized to total protein concentrations. The graphs show the square root (SQRT) of IL-6 and KC concentrations in pg/mg at several time points from control, sham and MCAO mice. In sham mice, brain IL-6 and KC did not differ from control mice at any time points. (A) Brain IL-6 concentration in the hemisphere ipsilateral to the lesion in MCAO+vehicle mice increased at 7 h compared with control mice (0 h) and with the 4 h time point. A non-significant increase of brain IL-6 in MCAO+vehicle and MCAO+D-JNKI1 mice was seen at 48 h (MCAO+vehicle: P = 0.25; MCAO+D-JNKI1: P = 0.32; plain columns). There was no significant difference in brain IL-6 release between vehicle- and D-JNKI1-treated mice at any time points. In MCAO+D-JNKI1 mice, IL-6 concentrations at 48 h remained significantly higher than at 4 h and 7 h and decreased significantly at 5 d (P = 0.02). (B) Brain KC concentration in the ipsilateral hemisphere of MCAO mice increased slightly at 4 h in both groups (MCAO+vehicle: P = 0.08; MCAO+D-JNKI1: P = 0.04) and at 48 h (MCAO+vehicle: P = 0.27; MCAO+D-JNKI1: P = 0.17) compared with sham mice. KC concentrations in MCAO + D-JNKI1 mice at 48 h remained significantly higher than control mice and decreased significantly at 5 d (P = 0.006). Matched pairs analysis between the ipsilesional (ipsi, plain columns) and contralesional (contra, dashed columns) hemispheres showed that there is an increase in (A) brain IL-6 at 7 h and 48 h after MCAO in both groups and that (B) brain KC has already increased by 4 h and until 48 h in both MCAO groups compared with the contralesional hemisphere. Control mice: n = 3; sham mice: n = 3 to 5; MCAO + vehicle: n = 3 to 7; MCAO + D-JNKI1: n = 7 to 8. *P <0.05 and **P <0.02 indicates a significant difference. N.S.: not significant. Results are represented as mean ± SEM. When placed over a data point, ∞, ⊗ and × indicate a significant difference with concentrations in the same group at 0 h, 4 h and 7 h, respectively.