The protective or damaging effect of Tumor necrosis factor-α in acute liver injury is concentration-dependent.
The protective or damaging effect of Tumor necrosis factor-α in acute liver injury is concentration-dependent.
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DOI：
10.1186/s13578-016-0074-x
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发表时间：
2016
影响因子：
7.5
通讯作者：
Wei L
中科院分区：
文献类型：
--
作者：
Dong Y;Liu Y;Kou X;Jing Y;Sun K;Sheng D;Yu G;Yu D;Zhao Q;Zhao X;Li R;Wu M;Wei L
炎性细胞因子在调节损伤性疾病中是重要的。肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）是一种强有力的炎性细胞因子，在机体防御反应中起主导作用。然而，TNF-α在急性肝损伤中的具体作用尚不清楚。本文报道了肿瘤坏死因子-α（TNF-α）对四氯化碳（CCl_4）所致急性肝损伤的具体作用及其可能机制。将SD雄性大鼠等分为9组。大鼠皮下注射CCl_4（1 ml/kg）。在注射CCl 4前15 min腹腔注射TNF-α抑制剂Enbrel，剂量分别为0、0.25、0.5、1、2、4和8 mg/kg。24 h后处死大鼠。用全自动生化分析仪测定血清ALT和AST。ELISA法测定血清TNF-α水平。HE染色观察肝组织形态学变化。免疫组化法和Tunnel试剂盒检测肝细胞凋亡。采用RT-PCR方法检测IL-4、IL-6、IL-8、IL-β和IFN-γ等炎症因子的表达。Western blotting和RT-PCR检测NF-κB信号通路和抗凋亡基因Bcl-2、Bcl-XL、FHC、XIAP的表达。肝功能的变化在持续增加Enbrel的整个过程中呈明显的“V”形。随着Enbrel剂量从0逐渐增加到1 mg/kg，血清TNF-α被阻断，ALT和AST随着TNF-α的增加而逐渐降低，肝细胞凋亡数也逐渐减少，在1 mg/kg时降至最低。随着Enbrel从1 mg/kg逐渐增加到8 mg/kg，ALT、AST和肝细胞凋亡反而增加，并在8 mg/kg Enbrel时达到最大。HE染色显示，急性肝损伤中，Enbrel 8 mg/kg组肝细胞脂肪变性程度最重，0 mg/kg组次之，1 mg/kg组最轻。Western-blotting和RT-PCR显示，随着TNF-α浓度的增加，NF-κB、p-IκBα和抗凋亡基因Bcl-XL、FHC、XIAP、Bcl-2表达减少。提示TNF-α在急性肝损伤中具有双重作用。其调控可能是通过NF-κB信号通路和抗凋亡的共同作用。同时，本研究结果为急性肝损伤的临床治疗提供了参考。本文的在线版本（doi：10.1186/s13578-016-0074-x）包含补充材料，可供授权用户使用。
Inflammatory cytokine is important in modulating injured diseases. Tumor necrosis factor-α (TNF-α), one of potent inflammatory cytokines, plays a dominant role in host defense reaction. However, the concrete effect of TNF-α on acute liver injury is totally unclear. Here we reported the concrete effect and possible mechanisms of TNF-α on acute liver injury induced by carbon tetrachloride (CCl4). SD male rats were equally divided into nine groups. CCl4 (1 ml/kg) was subcutaneously injected into the rats. Enbrel, a TNF-α inhibitor, were intraperitoneally injected at dose of 0, 0.25, 0.5, 1, 2, 4 or 8 mg/kg 15 min before the CCl4 injection. 24 h later, rats were sacrificed. Serum ALT and AST were measured with an autoanalyzer. Serum TNF-α were measured by ELISA. HE staining was used to observe the liver tissue morphology. Hepatocellular apoptosis were tested by immunochemistry and Tunnel kit. Inflammatory factors, involve IL-4, IL-6, IL-8, IL-β and IFN-γ were detected by RT-PCR. The NF-κB signal pathway and anti-apoptotic genes include Bcl-XL, FHC, XIAP and Bcl-2 were measured by western-blotting and RT-PCR. The change of liver function presented an obvious “V” shape in the whole process of persistently increased Enbrel. As Enbrel was increased gradually from 0 to 1 mg/kg, serum TNF-α were blocked, ALT and AST were gradually decreased as TNF-α as well as the numbers of hepatocellular apoptosis, and were declined to the minimum at 1 mg/kg Enbrel. As Enbrel was increased gradually from 1 to 8 mg/kg, ALT, AST and hepatocellular apoptosis were increased instead, and reached to the maximum at 8 mg/kg Enbrel. HE showed that the seriousness of hepatocellular steatosis was the most at 8 mg/kg Enbrel, and second at 0 mg/kg, the weakest at 1 mg/kg in the acute liver injury. Western-blotting and RT-PCR showed NF-κB, p-IκBα and antiapoptotic genes include Bcl-XL, FHC, XIAP, Bcl-2 were decreased as TNF-α was blocked by increased Enbrel. Our results suggested that TNF-α had a dual role in acute liver injury. It was regulated might via the corporate effect of NF-κB signal pawahway and anti-apoptosis. Meanwhile, our findings provide a reference for clinical treatment of acute liver injury. The online version of this article (doi:10.1186/s13578-016-0074-x) contains supplementary material, which is available to authorized users.