Table 1.
Cytokines and chemokines after SCI.
| Item | Detection timeframe | Roles | Reference |
|---|---|---|---|
| IL-1α | (i) Early 15 min, PL at 6 h AI | (i) Important alarmin that induces inflammatory response (ii) Enhances vascular permeability (iii) Augments lymphocyte recruitment |
[7, 88, 163] |
|
| |||
| IL-1β | (i) Its production starts from 3 to 24 h, PL 12 h AI (ii) Upregulation at 14 days |
(i) Astrocytic glutamate transporter inhibitor (ii) Vascular permeability enhancer and lymphocyte recruiter (iii) Low concentrations: (a) Induces adhesion molecules (b) Increases neurotrophin expression (c) Mediates leukocyte activation/recruitment (iv) High concentrations activate the expression of NFκβ, AP1, ATF, COX-2, iNOS, and proinflammatory proteases in astrocytes, neutrophils, monocytes, and microglia |
[104, 163] |
|
| |||
| IL-6 | (i) Early production at 15 min AI and could be found up to 3–24 h AI (ii) Detected serum levels 1 h AI, PL 24 h |
(i) Activates PMN, macrophages, and microglia (ii) Induces the following: (a) iNOS enzyme in astrocytes, neutrophils, monocytes, and microglia (b) IL-17 production (iii) IL1β-like effects |
[118, 136, 137] |
|
| |||
| TNFα | (i) Early production at 15 min AI (ii) Upregulated 1–3 h AI with PL at 1–3 days AI |
(i) Principal promoter of Wallerian degeneration (ii) Promotes immediate neutrophil recruitment to lesion site by the induction of adhesion molecules and IL-8 release (iii) iNOS induction in microglia, astrocytes, neutrophils, and monocytes |
[118, 136, 137, 148, 182–184] |
|
| |||
| LIF | (i) Upregulated from 3 to 24 h AI | (i) Microglia/macrophage activator (ii) Overexpression increases macrophage/microglia proliferation and astrocytic activation |
[24, 101] |
|
| |||
| IFNγ | (i) Detected from 1 to 12 h AI | (i) TCD8+ cytolytic response induction (ii) Principal inductor of MHCI (STAT1 phosphorylation) (iii) Promotes the following: (a) Proinflammatory cytokines and chemokines (b) CNS macrophage recruitment (c) Activation of CNS resident and infiltrating APC populations (iv) Low concentrations promote synaptic circuitry homeostasis |
[118, 192] |
|
| |||
| IL-4 | (i) High levels 24 h AI, concentrations remain during 7 days and decrease 3 days AI | (i) Neuroinflammatory regulation in various pathological conditions (ii) Confers regenerative properties to macrophages (iii) Controls free radical production in peripheral macrophages and microglia |
[166, 193–199] |
|
| |||
| IL-13 | (i) Detected 1 day AI | (i) Macrophage activation onto M2 phenotype | [166, 199] |
|
| |||
| IP-10/CXCL10 | (i) Expressed locally 30 min AI, increases at 1 h, PL at 6 h. Remains increased up to 5 days and decreases to the baseline by day 14 | (i) Recruits CD4 Th1 cells via CXCR3AR (ii) Inhibits angiogenesis, growth, and chemotaxis of endothelial cells via the CXCR3BR |
[95, 184, 200] |
|
| |||
| IL-17 | (i) Detected from 1 h AI, PL at 24 h, and barely detected up to 72 h AI | (i) Inflammation in autoimmune diseases | [201–204] |
|
| |||
| MIP-1α/CCL4 | (i) Locally produced from 30 to 60 min AI, PL 3–6 h, decreases by 1 day and remains barely detected up to 24 days AI | (i) Macrophage infiltration | [200, 205–207] |
|
| |||
| MIP-1β | (i) Detected 3–6 days AI, remains barely detected up to (ii) 24 days AI |
(i) Macrophage infiltration | [200, 205–207] |
|
| |||
| MCP1/CCL2 | (i) Detected from 1 h AI with PL at 24 h and remains low up to 24 days AI | (i) Macrophage and PMN infiltration mediator | [106, 184, 200, 205, 206] |
min: minutes; AI: after injury; PL: peak levels.