Fig. 2

Depiction of cytokine regulation following SCI in rodent models. A literature search was conducted and relevant data regarding significant cytokine regulation was collected at various timepoints. Data is presented as a percentage of studies that found significant changes in cytokine protein or mRNA expression levels compared to sham or naïve controls (p < 0.05). The number of papers used for each timepoint is listed at the top of each bar. A Changes in IL-1β levels after SCI [17, 21, 37, 38, 40,41,42,43, 45,46,47, 66,67,68, 85, 87,88,89, 94, 106, 107, 169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187]. The proinflammatory cytokine IL-1β shows consistent upregulation in the acute phase following SCI. However, there are some discrepancies as to whether IL-1β remains upregulated several days after injury and the second surge 14 days was only observed in mice. B Changes in TNFɑ levels after SCI [17, 36,37,38,39,40,41,42, 45,46,47,48, 66,67,68,69, 85, 87,88,89, 94,95,96, 107, 121, 169,170,171,172,173,174,175,176,177,178,179,180, 182,183,184,185,186,187,188,189]. The majority of studies show an upregulation of the proinflammatory cytokine TNFɑ immediately following SCI and persisting several days after injury. C Changes in IL-6 levels after SCI [17, 37, 38, 40,41,42, 45, 47, 66,67,68, 84, 85, 87,88,89,90, 93, 95, 96, 107, 121, 173, 174, 176, 178, 183, 184, 186,187,188,189]. Consistent upregulation of the proinflammatory cytokine is seen in the first 24 h following injury before returning to baseline levels by 7-day post-injury. D Changes in IL-1ɑ levels after SCI [17, 38, 40, 66, 84, 87, 90, 95]. The proinflammatory cytokine IL-1ɑ is upregulated in a similar manner to its isoform IL-1β, though IL-1β plays a more significant role following SCI [132, 133]. E Changes in IFN-γ levels after SCI [17, 38, 48, 87, 90, 95]. The relative change in IFN-γ expression following SCI remains controversial, as shown by the conflicting data presented. It appears to be upregulated in mice and downregulated in rats after 24 h. F Changes in MCP-1 levels after SCI [17, 38, 47, 84, 85, 87,88,89,90, 93, 121]. While there is some debate surrounding the regulation of the MCP-1 chemokine immediately after injury (1 h to < 6 h), nearly all data collected shows that MCP-1 expression levels elevate quickly and remain upregulated for several days. G Changes in IL-10 levels after SCI [17, 21, 38, 46, 47, 66, 85, 87,88,89,90, 96, 170, 173,174,175,176]. A delayed response is seen with IL-10 showing mixed results until upregulation at 3–7 days after injury. The anti-inflammatory cytokine returns to baseline levels by 14 days. H Changes in IL-4 levels after SCI [7, 17, 38, 47, 48, 66, 70, 87]. While some studies show increased expression of the anti-inflammatory IL-4, most researchers did not observe a change in IL-4 levels. I Changes in IL-13 levels after SCI [17, 38, 47, 48, 87, 90]. Previous studies display conflicting data surrounding the regulation of IL-13 after injury, where it was upregulated in mice and downregulated in rats 3 days hours post-injury