Toll样受体4参与小鼠肝脏缺血/再灌注损伤

Toll-like receptor 4 involvement in hepatic ischemia/reperfusion injury in mice.

作者信息

Wu He-Shui, Zhang Jin-Xiang, Wang Lin, Tian Yuan, Wang Hui, Rotstein Ori

机构信息

Department of General Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.

出版信息

Hepatobiliary Pancreat Dis Int. 2004 May;3(2):250-3.

PMID:15138120

Abstract

BACKGROUND

Toll-like receptor 4 (TLR4) is involved in innate immunity by recognizing endotoxin resulting in a burst of inflammatory cascade. We investigated the relation between activation of TLR4 and liver injury in partial hepatic ischemia/reperfusion (I/R) injury in mice.

METHODS

TLR4-deficient mice (C3H/Hej) and wild type mice (WT, C3H/Heouj) were used in the model of I/R injury. Partial hepatic ischemia was produced by occlusion of inflow to the median and left lobes for 45 minutes. Blood was drawn at 1 and 3 hours after reperfusion. The blood was analyzed for aspartate aminotransferase (AST) and tumor necrosis factor alpha (TNF-alpha). TNF-alpha mRNA expression and myeloperoxidase (MPO) level in the ischemic lobes were examined by northern blot and myeloperoxidase assay respectively.

RESULTS

AST levels were significantly decreased in TLR4deficient mice compared with WT mice at both time points (WT: 1215.5+/-174.03, 2958.17+/-186.81 IU/L at 1 and 3 hours respectively vs TLR4def: 661.83+/-106.09, 1145.17+/-132.43 IU/L at 1 and 3 hours, mean+/-SD, 6 mice/group, t=-6.65 and -5.57, P<0.001). Consistent with the role of TNF-alpha in hepatic I/R, serum TNF-alpha was decreased in TLR4 deficient mice at 3 hours after reperfusion compared with WT (152.39+/-43.3 vs 249.12+/-51.89, n=6, t=-3.13, P<0.05). MPO level in the ischemic lobes in TLR4 deficient mice at 3 hours after reperfusion was significantly lower than that in WT mice (0.059 +/-0.004 vs 0.173+/-0.025, n=6, F=33.49, P<0.001). This difference appears to be mediated at the gene level since TLR4 deficient mice had decreased TNF-alpha mRNA expression at 1 hour after reperfusion compared with WT mice (80.3+/-28.8 vs 189.4+/-24.6, t=-3.25, P<0.05).

CONCLUSIONS

Compared with WT mice, TLR4-deficient mice appear to have a mild I/R injury. Regulation of TNF-alpha at mRNA level seems to have a critical effect. These suggest TLR4 be involved in the mechanism of hepatic I/R injury in mice.

摘要

背景

Toll样受体4（TLR4）通过识别内毒素参与固有免疫，从而引发炎症级联反应。我们研究了TLR4激活与小鼠部分肝脏缺血/再灌注（I/R）损伤中肝损伤之间的关系。

方法

将TLR4缺陷小鼠（C3H/Hej）和野生型小鼠（WT，C3H/Heouj）用于I/R损伤模型。通过阻断中叶和左叶的血流45分钟造成部分肝脏缺血。再灌注后1小时和3小时采集血液。分析血液中的天冬氨酸转氨酶（AST）和肿瘤坏死因子α（TNF-α）。分别通过Northern印迹法和髓过氧化物酶测定法检测缺血叶中TNF-α mRNA表达和髓过氧化物酶（MPO）水平。

结果

在两个时间点，TLR4缺陷小鼠的AST水平均显著低于WT小鼠（WT：1小时和3小时分别为1215.5±174.03、2958.17±186.81 IU/L，而TLR4缺陷小鼠：1小时和3小时分别为661.83±106.09、1145.17±132.43 IU/L，均值±标准差，每组6只小鼠，t=-6.65和-5.57，P<0.001）。与TNF-α在肝脏I/R中的作用一致，与WT小鼠相比，TLR4缺陷小鼠在再灌注后3小时血清TNF-α降低（152.39±43.3对249.12±51.89，n=6，t=-3.13，P<0.05）。再灌注后3小时，TLR4缺陷小鼠缺血叶中的MPO水平显著低于WT小鼠（0.059±0.004对0.173±0.025，n=6，F=33.49，P<0.001）。这种差异似乎是在基因水平介导的，因为与WT小鼠相比，TLR4缺陷小鼠在再灌注后1小时TNF-α mRNA表达降低（80.3±28.8对189.4±24.6，t=-3.25，P<0.05）。