Department of Orthopedics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China.
Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Shanghai Institute of Traumatology and Orthopedics, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Eur Spine J. 2018 Oct;27(10):2506-2517. doi: 10.1007/s00586-017-5363-5. Epub 2017 Oct 31.
Propionibacterium acnes may be considered a new pathogeny for disc degeneration, but its pathological role has remained unclear. This study was designed to determine whether the latent infection of P. acnes was associated with chronic inflammation in degenerated intervertebral discs via quantification of the levels of a series of cytokines and neutrophils.
Here, 76 degenerated intervertebral discs were harvested from patients with lower back pain and/or sciatica. Discs with and without P. acnes infection were distinguished and identified using anaerobic culture combined with 16S rDNA PCR and histological examination. Then, cytokines of TNF-α, IL-1β, IL-6, IL-8, MCP-1, MIP-1α, and IP-10, and the numbers of neutrophils were quantified and compared. The severity of disc degeneration and the prevalence of Modic changes were also evaluated between discs with and without P. acnes.
After anaerobic culture and PCR examination, 15 intervertebral discs were placed in the P. acnes-positive group. Another 15 discs were selected from the remaining bacteria-free samples and formed a matched P. acnes-negative group. IL-8, MIP-1α, MCP-1, IP-10, TNF-α, and neutrophils were much higher in P. acnes-positive group than that in the matched P. acnes-negative group. However, only IL-8, MIP-1α, and neutrophils were statistically significant. Furthermore, 7 of 15 P. acnes-positive samples were histologically positive and a subgroup analysis suggested that both histological and PCR-positive samples had the highest concentrations of cytokines of IL-8, MIP-1α, TNF-α, and MCP-1 and the greatest numbers of neutrophils. PCR-positive but histologically negative samples showed the second-greatest, and matched P. acnes-negative samples showed the fewest. However, the difference was only statistically significant between samples found positive under both histology and PCR and samples found negative for P. acnes. Finally, P. acnes-positive group had significantly lower height of intervertebral discs and there was a trend with higher proportion of Modic changes in P. acnes-positive group, but without statistical results.
Latent P. acnes infection was associated with chronic inflammation in degenerated intervertebral discs, especially in the samples with visible bacteria in histology, which manifested as increased numbers of cytokines and neutrophils. Discs with P. acnes infection had much severer disc degeneration and P. acnes-associated chronic inflammation may be the reason.
痤疮丙酸杆菌（Propionibacterium acnes）可能被认为是椎间盘退变的新病因，但它的病理作用仍不清楚。本研究旨在通过定量检测一系列细胞因子和中性粒细胞，确定痤疮丙酸杆菌的潜伏感染是否与退变椎间盘的慢性炎症有关。
本研究共采集 76 例腰痛和/或坐骨神经痛患者的退变椎间盘。通过厌氧培养结合 16S rDNA PCR 和组织学检查，区分和鉴定有无痤疮丙酸杆菌感染的椎间盘。然后，定量比较肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）、白细胞介素-8（IL-8）、单核细胞趋化蛋白-1（MCP-1）、巨噬细胞炎性蛋白-1α（MIP-1α）和干扰素-γ诱导蛋白-10（IP-10）的水平以及中性粒细胞的数量。比较有无痤疮丙酸杆菌感染的椎间盘的椎间盘退变严重程度和 Modic 改变的发生率。
经厌氧培养和 PCR 检查，15 个椎间盘被归入痤疮丙酸杆菌阳性组。从其余无菌样本中选择了另外 15 个椎间盘组成匹配的痤疮丙酸杆菌阴性组。与匹配的痤疮丙酸杆菌阴性组相比，痤疮丙酸杆菌阳性组的 IL-8、MIP-1α、MCP-1、IP-10、TNF-α 和中性粒细胞明显升高。然而，只有 IL-8、MIP-1α 和中性粒细胞有统计学意义。此外，15 个痤疮丙酸杆菌阳性样本中有 7 个组织学阳性，亚组分析表明，组织学和 PCR 均阳性的样本中 IL-8、MIP-1α、TNF-α 和 MCP-1 的细胞因子浓度最高，中性粒细胞数量最多。PCR 阳性但组织学阴性的样本次之，匹配的痤疮丙酸杆菌阴性样本最少。但只有组织学和 PCR 均阳性的样本与痤疮丙酸杆菌阴性样本之间的差异有统计学意义。最后，痤疮丙酸杆菌阳性组的椎间盘高度明显降低，且痤疮丙酸杆菌阳性组 Modic 改变的比例有升高趋势，但无统计学结果。
潜伏的痤疮丙酸杆菌感染与退变椎间盘的慢性炎症有关，尤其是在组织学可见细菌的样本中，表现为细胞因子和中性粒细胞数量增加。感染痤疮丙酸杆菌的椎间盘退变更严重，痤疮丙酸杆菌相关的慢性炎症可能是其原因。
