高迁移率族蛋白1在新生儿败血症中的表达与机制

目的 探讨高迁移率族蛋白1（HMGB1）在新生儿败血症中的表达与机制。方法 选取62例新生儿败血症患儿为败血症组，66例局部感染新生儿为局部感染组，70例健康新生儿为健康对照组。检测三组新生儿血清中IL-6、IL-8、IL-17、IL-23、C反应蛋白（CRP）和降钙素原（PCT）的含量，外周血单个核细胞中HMGB1、Toll样受体4（TLR4）、核转录因子κB（NF-κB）mRNA及TLR4、NF-κB蛋白的表达。将健康新生儿的外周血单个核细胞分为对照组、HMGB1处理组、HMGB1+TAK-242（TLR4抑制剂）组、HMGB1+PDTC（NF-κB抑制剂）组，检测各组TLR4、NF-κB、IL-8 mRNA及TLR4、NF-κB蛋白的表达。将健康新生儿的外周血单个核细胞分为对照组、LPS处理组、LPS+甘草甜素（HMGB1抑制剂）组，检测HMGB1、TLR4、NF-κB、IL-8 mRNA及TLR4、NF-κB蛋白的表达。结果 败血症组患儿血清中IL-6、IL-8、IL-17、IL-23、CRP、PCT含量均显著高于局部感染组和健康对照组（P < 0.05）。败血症组患儿外周血单个核细胞中HMGB1、TLR4、NF-κBmRNA及TLR4、NF-κB蛋白的相对表达量均显著高于局部感染组和健康对照组（P < 0.05）。HMGB1可以显著诱导外周血单个核细胞高表达TLR4、NF-κB mRNA及其蛋白（P < 0.05）；使用TAK-242可抑制TLR4、NF-κBmRNA及其蛋白的高表达，并进而抑制IL-8 mRNA的表达（P < 0.05）；使用PDTC可抑制NF-κB mRNA及其蛋白的高表达，并进而抑制IL-8 mRNA的表达（P < 0.05）。LPS可显著诱导HMGB1 mRNA，以及TLR4、NF-κBmRNA及其蛋白的高表达，进而刺激IL-8 mRNA的表达（P < 0.05）；使用甘草甜素可抑制HMGB1 mRNA的高表达，抑制TLR4、NF-κB mRNA及其蛋白的高表达，进而降低IL-8 mRNA的高表达（P < 0.05）。结论 HMGB1可能通过激活TLR4/NF-κB信号通路诱导IL-8等炎症因子的高分泌在新生儿败血症的发病中起重要作用，HMGB1阻断剂甘草甜素可抑制TLR4/NF-κB信号通路的活化及炎症因子的分泌。

Expression of high-mobility group box 1 in neonates with sepsis

Objective To study the expression of high-mobility group box 1 (HMGB1) in neonates with sepsis and its role in the pathogenesis of neonatal sepsis. Methods A total of 62 neonates with sepsis were enrolled as the sepsis group, 66 neonates with local infection were enrolled as the local infection group, and 70 healthy neonates were enrolled as the healthy control group. Serum levels of interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-17 (IL-17), interleukin-23 (IL-23), C-reactive protein (CRP) and procalcitonin (PCT) were measured. The mRNA expression of HMGB1, Toll-like receptor 4 (TLR4) and nuclear factor-kappa B (NF-κB) and the protein expression of TLR4 and NF-κB in peripheral blood mononuclear cells (PBMCs) were also measured. PBMCs from healthy neonates were divided into 4 groups:control, HMGB1 treatment, HMGB1+TAK-242 (a TLR4 inhibitor) treatment and HMGB1+PDTC (an NF-κB inhibitor) treatment, and the mRNA expression of TLR4, NF-κB and IL-8 and the protein expression of TLR4 and NF-κB were measured. PBMCs from healthy neonates were divided into another 3 groups:control, LPS treatment and LPS+glycyrrhizin (an HMGB1 inhibitor) treatment, and the mRNA expression of HMGB1, TLR4, NF-κB and IL-8 and the protein expression of TLR4 and NF-κB were measured. Results Compared with the local infection and healthy control groups, the sepsis group had significantly higher serum levels of IL-6, IL-8, IL-17, IL-23, CRP and PCT (P < 0.05), as well as significantly higher mRNA expression of HMGB1, TLR4 and NF-κB and protein expression of TLR4 and NF-κB in PBMCs (P < 0.05). HMGB1 significantly induced the mRNA and protein expression of TLR4 and NF-κB in PBMCs (P < 0.05). TAK-242 inhibited the mRNA and protein expression of TLR4 and NF-κB and mRNA expression of IL-8 (P < 0.05). PDTC inhibited the mRNA and protein expression of NF-κB and the mRNA expression of IL-8 (P < 0.05). LPS significantly induced the mRNA expression of HMGB1 and the mRNA and protein expression of TLR4 and NF-κB and then stimulated the mRNA expression of IL-8 (P < 0.05). Glycyrrhizin inhibited the mRNA expression of HMGB1 and the mRNA and protein expression of TLR4 and NF-κB and then reduced the mRNA expression of IL-8 (P < 0.05). Conclusions HMGB1 plays an important role in the pathogenesis of neonatal sepsis by activating the TLR4/NF-κB signaling pathway and inducing the secretion of inflammatory factors including IL-8. The HMGB1 blocker glycyrrhizin can inhibit activation of the TLR4/NF-κB signaling pathway and the secretion of inflammatory factors.