急性坏死性胰腺炎时肠道Toll样受体4的表达及其意义

Expression and significance of Toll-like receptor 4 in distal ileum in rats with acute necrotizing pancreatitis

目的:探讨急性坏死性胰腺炎(ANP)末端回肠组织中Toll样受体4(TLR4)的表达及其意义。方法:采用逆行胰胆管注射5%牛磺胆酸钠制作大鼠ANP模型(设为ANP组,40只),假手术组(20只)仅轻轻翻动胰腺3次后关腹。应用实时定量PCR检测不同组、不同时点末端回肠组织TLR4 mRNA表达变化,应用Western blot和免疫组化分析各组TLR4蛋白表达变化及组织学定位。结果:ANP组末端回肠组织TLR4 mRNA的表达为2.470±0.275,而假手术组为1.264±0.219,ANP时明显升高(P<0.05)。与假手术组相比,ANP组蛋白表达水平也显著升高(P<0.05)。TLR4 mRNA表达水平与肠黏膜通透性呈正相关(r=0.38,P<0.05),也和肠黏膜的病理学评分相关(r=0.47,P<0.01)。ANP组回肠黏膜表面,黏膜固有层的T淋巴细胞、B淋巴细胞、单核细胞、中性粒细胞、嗜酸粒细胞,黏膜下层的动静脉、纵形和环形肌层等处都有较强的TLR4的表达。结论:ANP时,末端回肠组织内TLR4 mRNA和蛋白表达上调,可能与ANP肠黏膜的病理改变及肠源性感染的发生、发展有关。

Objective To investigate changes and pathophysiological roles of the Toll-like receptor 4 gene （TLR4） in distal ileum in rats with acute necrotizing pancreatitis （ANP）. Methods Sixty SD rats were randomly divided into ANP group （n = 40） and sham-operation group （n=20）, TLR4 mRNA expression in distal ileum were measured by real-time quantitative reverse transcriptase polymerase chain reaction （RT-PCR）, and its protein expression and localization were determined by immunohistochemistry and Western blot. Results Compared to sham-operation group, TLR4 mRNA and protein level of ANP group increased significantly （ P 〈 0.05 ）. Western blot analysis demonstrated that the TLR4 protein level of ANP group also increased significantly （ P 〈 0.05 ）. The TLR4 mRNA level was correlated with pathological score of intestinal mucosa （r = 0.38 ,P 〈 0.05 ） and intestinal mucosa permeability （r = 0.47 ,P 〈 0.01 ） in ANP. Immunohistochemistry revealed that in ANP group, TLR4 protein were expressed with high positive rate in rat ileum mucosa surface, T and B lymphocyte, histoleucocyte and eosinocyte in lamina propria, arteriovenous in submucosa and longitudinal and annuliform musculus. Conclusion Expression of TLR4 gene mRNA and protein increases in the tissure of ANP distal ileum, its overexpression may correlate with intestinal mucosa injury and the development of enterogenic infection.