滤泡辅助性T细胞在急性肝衰竭小鼠模型中的变化及意义

目的:探讨滤泡辅助性T(T follicular helper,Tfh)细胞及相关细胞因子白细胞介素(interleukin,IL)-21在急性肝衰竭(acute liver failure,ALF)小鼠模型中的变化及意义。方法:将20只雌性C57BL/6小鼠随机分成2组,分别予脂多糖/D-氨基半乳糖或磷酸盐缓冲液(phosphate buffer solution,PBS)腹腔注射,6 h后采集血液、肝脏和脾脏组织标本。采用苏木精-伊红染色法分析肝脏病变情况;流式细胞术分析小鼠脾脏单个核细胞中Tfh细胞的频数;酶联免疫吸附试验分析血清中IL-21和肿瘤坏死因子α(tumor necrosis factorα,TNF-α)的水平。结果:ALF小鼠肝脏肿大而呈暗红色,肝细胞大量坏死和炎性细胞浸润,其血清中TNF-α及IL-21的水平均较正常对照组显著增高(P<0.01,P<0.05);而单个核细胞中CD4+CXCR5+、CD4+PD-1+、CD4+CXCR5+PD-1+T细胞频数亦较正常对照组显著升高(P<0.01)。结论:ALF小鼠脾脏单个核细胞中Tfh细胞频数显著增加,血清IL-21水平显著升高,推测Tfh细胞在ALF的发病过程中起重要作用,本研究结果可能为ALF的治疗提供新思路。

Changes and significance of T follicular helper cells in mice with acute liver failure

Objective： To investigate changes and significance of T follicular helper （Tfh） cells and related cytokine interleukin （IL）-21 in mice with acute liver failure （ALF）. Methods： Twenty female C57BL/6 mice were randomly divided into ALF group and PBS control group： mice were given lipopolysaccharide/D-galactosamine or PBS by intraperitoneal injection, respectively. Blood, liver and spleen samples were collected 6 h after the injection. Histological features of liver were examined using hematoxylin-eosin staining. Frequency of Tfh cells in mononuclear cells of spleen was detected by flow cytometry. Serum levels of cytokine tumor necrosis factor （TNF）-ot and IL-21 were measured by enzyme linked immunosorbent assay （ELISA）. Results： The liver of ALF group was dark red in color and enlarged; histopathologic examination showed significant hepatocellular necrosis and infiltration of inflammatory cells. Serum levels of TNF-α and IL-21 were significantly increased （P〈0.01） and frequencies of CD4＋CXCR5＋, CD4＋PD-1＋ and CD4＋CXCR5＋PD-1＋ T cells were significantly higher in mononuclear cells of spleen in ALF group （P〈0.001） when compared with control group. Level of serum IL-21 in ALF group was significantly higher than that in control group （P〈0.05）. Conclusions： Frequency of Tfh cells in mononuclear cells and level of serum IL-21 are significantly higher in ALF group. Abnormality in frequency of Tth cell and related cytokine might play an important role in the pathogenesis of ALF, and these might provide a new strategy for the treatment of ALF.