TNF-α and IL-17A act synergistically to induce CXCL-1 expression in astrocytes. (A) Relative gene expression of CXCL-1 and CCL2 in the stroked brain. RNA was obtained from the affected hemisphere 6, 12, and 24 hours after MCAO (n = 6 mice). (B) Relative gene expression of CXCL-1 and CCL2 in the stroked brain of wt, Rag1^−/−, Tcrd^−/−, and Il17ra^−/− mice. RNA was obtained from the affected hemisphere 24 hours after MCAO (n = 6 mice). (C) Changes in CXCL-1 and CCL-2 RNA expression in primary astrocytes 24 hours after stimulation with TNF-α, IL-17A, or both. (D) Quantification of CCL-2 and CXCL-1 secreted by primary astrocytes 24 hours after cytokine stimulation by ELISA. Graphs show means ± SDs of 5 independent experiments and the statistical significance. (E) Frequency of neutrophils eluted from the ischemic hemispheres of Cxcr2^−/− mice in comparison with wt mice 3 days after MCAO. The graphs show the means ± SDs of 9-12 animals per group analyzed 3 days after MCAO in 3 or 4 independent experiments. A representative dot plot displaying gated CD45⁺ cells is shown in the right panel. (A-D) One-way ANOVA with Bonferroni posthoc test. *P < .05, **P < .01, ***P < .001. (E) Student t test with **P < .01.