Fig. 2

Age exacerbates inflammatory gene signatures after TBI. Overall, the aged TBI group had exacerbated responses, whether up- or downregulated, to TBI when compared to their young TBI counterparts. Select genes from each of the three clusters were validated using n = 8/group. a Genes from the “green” hierarchical cluster aligned with pooled responses observed in the array. Specifically, detailing that age significantly affected, via downregulation, gene expression of CD163, CX3CL1, and JAK2, but not JMJD3, which had only a visual trend. b Genes selected from the “red” cluster for analysis showed marked upregulation of CD86, CCL5, CCL8, and CCL7 in the aged TBI group. c Similarly, genes from the “aquamarine” hierarchical cluster all displayed significant upregulation in expression response as a function of age, compared to young TBI. YT young TBI; magenta, AS aged sham; aquamarine, AT aged TBI; orange. Young sham expression values are equivalent to zero. Data were analyzed using two-way ANOVA with Tukey’s PSD for multiple comparisons and presented as mean + SEM. *p < 0.05, **p < 0.01 comparing young TBI to young sham. ^# p < 0.05, ^## p < 0.01 comparing aged TBI to young TBI