脓毒症小鼠脾脏、肾脏及心脏PD-L1表达变化

Changes of PD-L1 expression in the spleen,kidney and heart of septic mice

目的观察脓毒症小鼠脾脏、心脏和肾脏组织程序性细胞死亡配体-1(programmed cell death ligand-1,PD-L1)表达变化。方法 40只C57BL/6小鼠随机分为脓毒症模型组及假手术组,每组20只。采用盲肠结扎穿孔法造模,造模成功后两组小鼠分别在24 h(n=10),48 h(n=10)时间点处死。取脾脏、心脏和肾脏组织用免疫组化法检测各组织PD-L1表达;用流式细胞仪检测各组外周血单核细胞PD-L1表达;收集腹水用酶联免疫吸附法检测腹水内毒素水平。结果模型组24 h和48 h脾脏、肾脏PD-L1表达明显增高,与假手术组比较差异有统计学意义(P<0.05);各组心肌细胞未见PD-L1表达。模型组脾脏PD-L1阳性细胞出现在红髓和脾小体,肾脏阳性细胞是肾小管上皮细胞。模型组24 h和48 h单核细胞PD-L1的表达均较假手术组升高(P<0.01)。模型组腹水内毒素水平均较假手术组高(P<0.01)。结论脓毒症小鼠脾脏和肾脏PD-L1表达升高,PD-L1可能参与脓毒症发生发展。

Objective To explore the changes of PD-L1 expression in the spleen,kidney and heart of septic mice. Methods Forty C57 mice were randomly divided into： sepsis model group and sham group（ n = 20 in each group）. Sepsis model was induced by cecal ligation and puncture. The mice were sacrificed at 24 h（ n = 10） and 48 h（ n = 10） in two groups,respectively. Spleen,kidney and heart at 24 h and 48 h were obtained to detect the PD-L1 expression by immunohistochemistry. Peripheral blood samples at 24 h and 48 h were taken to detect the PD-L1 expression in monocytes by flow cytometry. Ascites at 24 h and 48 h were collected to detect the endotoxin level by enzyme-linked immunosorbent assay. Results Compared with sham group,PD-L1 expression in the spleen and kidney was increased at 24 h and 48 h in sepsis model group（ P 〈0. 05）. PD-L1 expression was not observed in the heart in sepsis model group and sham group. Positive cells of PD-L1 expression were found in the red pulp,splenic corpuscle and renal tubules in sepsis model group. Compared with sham group,PD-L1 expression in the monocytes was increased in sepsis model group（ P〈 0. 01）,and the endotoxin level in ascites was also increased（ P〈 0. 01）. Conclusion PD-L1 expression is increased in spleen and kidney of sepsis mice. Increased PD-L1 expression may be involved in the development of sepsis.