PURPOSE Sciatic symptoms due to lumbar disc herniation are likely to be caused not solely by mechanical compression of the nerve root, but also by pain-inducing elements from inflammatory processes. Key components in the inflammatory reaction are M1 and M2 macrophages, with the M1 type being associated with pro-inflammatory processes and M2 with anti-inflammatory-processes. METHOD The present systematic review summarizes all studies on associations between M1 and M2 macrophages and their related inflammation factors and pain symptoms in lumbar disc herniations. Literature search was performed using an optimally sensitive search string. Studies were selected for inclusion by means of predefined inclusion and exclusion criteria and subsequently graded for risk of bias. A total of 14 studies were included. Overall risk of bias was moderate (8/14), and three studies had high risk of bias and three has low risk of bias. RESULTS Regarding M1-related cytokines, high levels of TNF-α, TNFR1, IL-6, IL-8, and IFN-γ were all associated high VAS scores. In contrast, high levels of TNFR2 were associated with lower VAS scores. Moreover, no associations were found for IL-1a and IL-1β. Results regarding M2-related cytokines revealed the opposite: high levels of both IL-4 and IL-10 were associated with lower VAS scores. No associations were established for TGF-β. Moreover, the presence of macrophages (CD68) was negatively associated with VAS scores. CONCLUSION While M1-related pro-inflammatory cytokines worsen pain symptoms, M2-related anti-inflammatory cytokines alleviate pain symptoms. Nevertheless, the present evidence is limited, and further research on the underlying pathophysiological mechanism in sciatica is required. These slides can be retrieved under Electronic Supplementary Material.

中文翻译：

---

巨噬细胞相关的细胞因子表达在腰椎间盘突出症中的矛盾作用：系统评价。

目的腰椎间盘突出症引起的坐骨神经痛症状可能不仅是由于神经根的机械压迫引起的，而且还可能是由炎症过程引起的疼痛引起的。炎症反应的关键成分是M1和M2巨噬细胞，其中M1类型与促炎过程相关，而M2与抗炎过程相关。方法本系统综述总结了关于M1和M2巨噬细胞及其相关炎症因子与腰椎间盘突出症疼痛症状之间关联的所有研究。使用最佳敏感的搜索字符串进行文献搜索。通过预定义的纳入和排除标准选择要纳入的研究，然后对偏倚风险进行分级。总共包括14个研究。总体偏见风险为中等（8/14），三项研究有偏见的风险高，三项研究有偏见的风险低。结果关于M1相关的细胞因子，高水平的TNF-α，TNFR1，IL-6，IL-8和IFN-γ均与高VAS评分相关。相反，高水平的TNFR2与较低的VAS分数相关。此外，未发现与IL-1a和IL-1β相关。关于M2相关细胞因子的结果显示出相反的结果：IL-4和IL-10的高水平与较低的VAS分数相关。没有建立与TGF-β的关联。此外，巨噬细胞（CD68）的存在与VAS评分呈负相关。结论虽然M1相关的促炎细胞因子可减轻疼痛症状，但M2相关的消炎细胞因子可缓解疼痛症状。但是，目前的证据是有限的，尚需进一步研究坐骨神经痛的潜在病理生理机制。这些幻灯片可以在电子补充材料下找到。