肿瘤坏死周子-β1对脓毒症大鼠Toll样受体R4及核周子-κB表达的影响

Effects of tumor necrosis factor-β1 on expression of monocyte Toll-like receptor-4 and hepatic nuclear factor-κB in sepsis： experiment with rats

目的动态观察TGF-β1对脓毒症大鼠外周血单核细胞Toll样受体（Toll-likereceptor）TLR4、TNF-α及肝脏NF-κB表达的影响。方法120只SD大鼠接受盲肠结扎穿孔法（CLP）建立脓毒症模型，并随机均分为10组：脓毒症模型2h、6h、12h、24h、和48h组（造模后0．5h尾静脉注射生理盐水1m1），TGF-β1干预2h、6h、12h、24h、和48h组[造模后0．5h尾静脉注射TGF-β120ng／（ml·250g）]。另12只SD大鼠用作对照组。于各时间点分别处死大鼠，利用流式细胞术检测外周血单核细胞表面TLR4表达变化，酶联免疫吸附分析法（ELISA）检测外周血TNF-α、肝脏NF-κB浓度。结果CLP术后6～12hTLR4在外周血单核细胞表达明显减少，12h最低；肝脏组织中NF-κB的浓度从术后6h起即显著高于对照组，24h时达到最高并维持到48h后。TGF-β1干预组单核细胞TLR4表达显著低于脓毒症模型组，伴随肝脏表达NF-κB减少，但外周血TNF-α浓度明显升高。结论在脓毒症，TGF-β1能下调单核细胞TLR4及肝脏NF-κB的表达，但TNF-α的生成增加。TGF-β1在脓毒症炎症反应过程中发挥复杂作用，可能并非通过TLR4来影响炎症因子的生成。

Objective To investigate the effects of tumor necrosis factor （TGF）-β1 on the expression of monocyte Toll-like receptor-4 （TLR-4） and hepatic nuclear faetor-κB （NF-kB） in sepsis. Method 120 SD rats underwent cecal ligation puncture （CLP） to establish models of sepsis and randomly divided into 10 equal groups： sepsis model 2 h, 6 h, 12 h, 24 h, and 48 h groups undergoing injection of normal saline via the caudal vein 0.5h after the CLP, and TGF-β1 intervention 2 h, 6 h, 12 h, 24 h, and 48 h groups undergoing injection of TGF-β1 20 ng/ml · 250 g via the caudal vein 0.5 h after the CLP. Another 12 rats were used as normal control guoup. At the different above-mentioned time points 12 rats from each sub-group were killed. Flow cytometry was used to detect the variation of monocyte TLR-4 levels in peripheral blood, enzyme linked immunosorbent assay （ELISA） was used to detect the variation of TNF-α level in peripheral blood and variation of NF-κB in hepatic cells. Results The peripheral blood monocyte TLR-4 expression decreased since 6h after CLP and minimized 12h after CLP. The TLR-4 level of the TGF-β1 intervention 2 h, 24 h, and 48h subgroups were all significantly lower than those of the corresponding sepsis model subgroups （all P 〈 0.05）. The NF-K B level in hepatic cells increased since 6h after CLP and maximized 12-48h after CLP. The liver tissue NF-κB levels 6, 12, and 24h after CLP of the TGF-β1 subgroups were all significantly higher than those of the corresponding sepsis subgroup （allP〈 0.05）. The TNF-α levels in peripheral blood 2-48 h after CLP were all significantly higher than those of the control group , with 2 peaks at the 2h and 12h time points （all P〈 0.05）. The TNF-α levels at different time points of the TGF-β1 subgroups were all significantly higher than those of the sepsis subgroups （all P〈 0.05）.Condusion TGF-β1 down-regnlates the monocytes TLR4 expression and hepatic NF-κB expression, and facilitates the formation of the proinflammatory mediator TNF-α. However, its modulating mechanism is complicated, the change of TNF-α may not be caused through direct regulation on the monocyte TLR4 level in peripheral blood.