不同细胞表面TLR4表达对小鼠重症急性胰腺炎中性粒细胞招募的作用

Expression of toil-like receptor on different cell surface in PMN recruiting in severe acute pancreatitis

目的探索髓系细胞（中性粒细胞、血小板）及内皮细胞表面TLR4表达在重症急性胰腺炎中性粒细胞招募中的作用。方法采用C3H／He—J和C3H／He—N小鼠通过骨髓移植的方法制作“髓系细胞TLR4^-/-和内皮细胞TLR4^＋/＋”（A组）及“髓系细胞TLR4^＋/＋和内皮细胞TLR4^-/-”（B组）嵌合体小鼠及“髓系细胞TLR4^＋/＋和内皮细胞TLR4^＋/＋”（C组）及“髓系细胞TLR4^-/-和内皮细胞TLR4^-/-”（D组）纯合体小鼠，腹腔注射蛙皮素、尾静脉注射脂多糖复制SAP模型，检测血浆淀粉酶、PCR测外周血粒细胞TLR4、免疫组化检测胰腺组织内TLR4的表达、胰腺组织萘酚AS—D氯乙酸脂酶染色计数、MPO活性。结果各实验组小鼠血浆淀粉酶升高；B、C两组外周血粒细胞TLR4mRNA表达高于A、D两组（P〈0．05）；A、C两组胰腺组织内TLR4阳性，B、D两组阴性；A、C两组AS—D计数高于B、D两组；A、C两组MPO活性亦明显高于B、D两组（P〈0．05）。结论内皮细胞而非外周血粒细胞在重症急性胰腺炎中性粒细胞招募聚集中起关键作用。

Objective To investigate the significance of expression of toll-like receptor on medullary system cell and endothelial cell surface in PMN recruiting in severe acute pancreatitis. Method In this study,26 C3H/He-J mice and 26 C3H/He-N mice were devided into 4 groups by bone marrow transplantation：group A, mosaic of medullary system cell TLR4^ -/- and endothelial cell TLR4 ^＋/＋ , group B, mosaic of medullary system cell TLR4 ^＋/＋ and endothelial cell TLR4^-/- ;group C, homozygote of TLR4^＋/＋ ;group D, bomozygote of TLR4^-/-. SAP was induced to all these mice. Amylase, TRIA of granular cell in peripheral blood,TRIA expression in pancreas, Naphthol AS-D ehloroacetate esterase, MPO activity were tested. Results Amylase level increased in all mice, there was no differences of the amylase level among groups, TRIA of granular cell in peripheral blood in group B and C was significant higher than A and D（P 〈0.05）, TLR4 in pancreas were positive in group A and C, negative in group B and D, AS-D count and MPO activity in group A and C were higher than that in group B and D （ P 〈 0.05 ）. Conclusions It was endothelial cell, not peripheral blood granulocyte, that plays a key role in recuiting neutrophils that triggers severe acute pancreatitis.