TLR4信号转导通路活化在皮瓣缺血再灌注损伤中的作用

The role of toll like receptor-4 signal pathways activation in ischemia-reperfusion injury of island skin flap

目的探讨Toll样受体4（Toll—like receptors4，TLR4）在皮瓣缺血再灌注（ischmeia-reperfusion，I／R）损伤中的意义。方法将50只雄性sD大鼠进行编号，盲视下随机分为：假手术组（10只）、I／R组（20只）、TLR4抑制剂组（20只）。制备右下腹岛状皮瓣I／R模型。TLR4抑制剂组处理组于再灌注前静脉注射E5564（5mg／kg），分别于缺血再灌注后1、2、4和6h，采用免疫组化学法检测TLR4在皮瓣组织中的表达及分布，并行组织学观察。于术后7d，应用图像分析软件计算皮瓣存活比例。应用SPSS18．0进行统计分析，两组间比较采用F检验。结果免疫组织化学法显示I／R组比TLR4抑制组TLR4表达明显增强，且阳性部位主要是血管壁细胞及中性粒细胞。TLR4抑制剂组再灌注后TLR4活性受到抑制，中性粒细胞浸润及组织水肿程度较I／R组明显改善。术后7dI／R组皮瓣存活比例为（51．70±7．62）％，TLR4抑制剂组皮瓣存活比例明显增高，达（80．31±11．63）％，与I／R组比较差异有统计学意义（P〈0．01）。结论大鼠皮瓣缺血再灌注损伤后，皮瓣组织TLR4的表达上调中性粒细胞浸润增多。E5564能通过抑制TLR4活化，减少中性粒细胞浸润，减轻皮瓣I／R损伤。

Objective To determine the role of toll like receptor-4 signal pathways activation in ischemia-reperfusion injury of island skin flap. Methods A totol of 50 adult male SD rats were randomized into 3 groups ： sham-operated group （ n = 10）, ischemia/reperfusion group （ n = 20） and TLR4 inhibitor-eritoran tetrasodium （E5564）-treated group（n =20）. The inguinal island skin flaps models were set up. A bolus of E5564 （5 mg/kg） was infused intravenously 60 min before reper fusionm. TLR4 binding activity in flap tissue was analyzed at 1, 2, 4 and 6 h of reperfusion by immunohistochemical technique and flaps were assessed histologically at 6 h of reperfusion. The viability of flaps was assessed 7 days postoperatively. Results Exprerssion TLR4 in skin flap tissue was significantly increased in I/R group, compared with E5564-treated group. Immunohistochemical exam showed TLR4 mainly expressed in skin flap vessel wall and PMN membrane. Marked neutrophil infiltration and edema was observed in I/R group, while less neutrophil infiltration was observed in E5564-treated group. In the E5564-treated group, the survival of flaps was （80.31 ＋ 11.63 ） % , which was significantly greater than that in the I/R group （51.70 ~ 7.62） % （P 〈 0.01 ）. Conclusion After ischemia-reperfusion injury in rats, the expression of TLR4 increased in the skin flap tissue with excessive neutrophil infiltration. Administration of E5564 can significantly improve flap survival by regulating the early activation of TLR4 and suppressing neutrophil infiltration within the flap.