肝脏自然杀伤细胞对梗阻性黄疸小鼠模型急性肝损伤的影响及其机制

Effect of liver natural killer cells on acute liver injury in mice with obstructive jaundice and its related mechanisms

目的探讨肝脏自然杀伤（NK）细胞对梗阻性黄疸小鼠模型急性肝损伤的影响及其机制。方法将80只小鼠随机分为A组：手术±聚肌胞（PolyI：C）组（n=20）、B组：手术±磷酸盐缓冲液（PBS）组（n=20）、C组：假手术±PolyI：C组（n=20）、D组：假手术±PBS组（n=20）。手术组行胆总管双重结扎术构建梗阻性黄疸模型，假手术组仅游离胆总管。A、C组腹腔注射PolyI：C，B、D组注射等量PBS作为对照。于第7天比较各组血清丙氨酸转氨酶（ALT）、肝组织病理学及实时荧光定量聚合酶链反应检测肝脏NK细胞表面标志（NK1．1）、肿瘤坏死因子相关凋亡诱导配体（TRAIL）及肿瘤坏死因子（TNF）-α mRNA表达量变化。结果手术组血清ALT[A：（562．33±173．28）U／L，B：（383．09±144．56）U／L]高于假手术组[C：（26．204-3．97）U／L，13：（25．38±4．63）U／L]，A组较B组升高（P〈0．05）。肝脏HE染色A组较B组坏死面积增大。NK1．1mRNA相对表达量A组为159．96±17．26、B组为36．04±4．42、C组为87．79±6．68、D组为1．00±0．25，各组比较差异有统计学意义（P〈0．01）。TRAILmRNA与TNF—αmRNA表达量分别为A组11．83±0．88、5．79±0．94，B组1．96±0．29、3．03±0．60，C组1．05±0．17、1．47±0．06，D组1．104-0．12、1．00±0．13，A组高于B组（P〈0．01），C组与D组比较差异元统计学意义（P〉0．05）。结论PolyI：C诱导小鼠NK细胞活化及肝内聚集，加重梗阻性黄疸小鼠肝损伤，其可能通过TRAIL途径参与梗阻性黄疸小鼠模型急性肝损伤。

Objective To explore the effect of liver natural killer （NK） cells on acute liver injury in mice with obstructive jaundice and its related mechanisms. Methods Eighty mice were randomly divid- ed into 4 groups： group A, operation ± polyinosinic- polycytidylic acid （Poly I： C） group; group B, op- eration ± phosphate buffer （PBS） group; group C, sham- operation ± Poly I： C group; group D,sham- operation ± PBS group. Operation groups underwent common bile duct ligation （BDL） to establish ob- structive jaundice models, and sham - operation groups only underwent dissociation of common bile duct. Poly I： C was injected to activate and induce accumulation of NK cells in mice livers. All the mice were sacrificed at 7th day after operation, the level of serum alanine aminotransferase （ALT） was detected, and the liver tissue received hematoxylin and eosin （HE） stain as well as the NK1.1, tumor necrosis factor- related apoptosis- inducing ligand （TRAIL）, and tumor necrosis factor （TNF） -α mRNA expression in the liver was analyzed by real - time polymerase chain reaction （PCR）. Results The levels of serum ALT were significantly higher in operation groups [A： （562. 33 ±173.28） U/L, B： （383.09 ± 144. 56） U/L] than those in sham - operation groups [ C ： 26. 20 ±3.97 ） U/L, D ： 25.38 ± 4. 63 ） U/L, P 〈 0. 01 ], and significantly higher in operation ± Poly I： C group than in operation ± PBS group （P 〈 0. 05 ）. Histologi- cal examination suggested hepatic tissue necrosis area increased in operation ± Poly 1： C group than in op- eration ± PBS group. The expression levels of NK1.1 mRNA showed significant difference among groups （A： 159.96±17.26, B： 36.04±4.42, C： 87.79±6.68, D： 1.00±0.25） （P〈0.01）. The relative expression levels of TRAIL, and TNF - α mRNA were highest in group A （ 11.83 ±0. 88 and 5.79 ± 0. 94）, followed by those in group B （ 1.96 ±-0. 29 and 3.03 ±0. 60）, group C （ 1.05 ±. 17 and 1.47 ± 0. 06 ） , and group D （ 1.05 ± 0. 17 and 1.47 -i-- 0.06 ）. There was no significant difference between group C and group D （ P 〉 0.05 ）. Conclusion Poly I： C activated and induced accumulation of NK cells in mouse livers, which aggravates acute liver injury in mice with obstructive jaundice. NK ceils might participate in acute liver injury in TRAIL - del±endent manner.