摘要目的 探讨四氯化碳(CCl4)诱导的肝纤维化模型大鼠血清辅助性T细胞1型和2型(Th1/Th2)细胞因子平衡对其肝脏β-连环蛋白(β-catenin)表达的影响.方法 将75只大鼠分为对照组、己酮可可碱干预实验组和肝纤维化模型组,采用ELISA法检测各组大鼠血清中Th1型细胞因子(IFN-γ,TNF-α)、Th2型细胞因子(IL-4,IL-6)和Ⅳ型胶原的水平;免疫组织化学法检测各组大鼠肝脏β-catenin的表达和分布及Ⅳ型胶原占肝组织面积的百分比;单向方差分析描述细胞因子的变化规律,并借助双变量相关分析研究β-catenin的表达与细胞因子以及肝纤维化的相关关系.结果 模型组大鼠血清Th2型细胞因子水平明显高于实验组,更高于对照组,其积分光密度(ILD)分别为50 043.6,34 256.7,10 101.5(F=71.260,91.732,均P<0.05);而其血清Th1型细胞因子水平明显低于实验组,更低于对照组(F=50.420,10.625,均P<0.05),细胞因子发生了Th2极化;其肝纤维化程度明显高于实验组,更高于对照组;模型组大鼠肝脏β-catenin的表达明显高于实验组,更高于对照组(=92.030,均P<0.05).β-catenin在3组肝组织中的表达强度与其血清Th2细胞因子水平及其肝脏Ⅳ型胶原面积百分比均呈显著正相关关系(r=0.560,P<0.01;r=0.757,P<0.01).结论 大鼠血清细胞因子的Th2极化上调其肝脏β-catenin的表达,促进肝纤维化的发生和发展;β-catenin可作为肝脏纤维化严重程度的反应指标.

abstractsObjective To investigate the effect of the balance between helper T lymphocyte (Th) 1 cytokines and Th2 cytokines in the serum of hepatic fibrosis rats induced by CCl4 on the expression of β-catenin in their livers. Methods Seventy-five rats were divided into control group,treatment group and model group. Hepatic fibrosis models were built by subcutaneous injection of CCl4in male Wistar rats, then rats in treatment group were treated with pentoxifylline(PTX) by intragastric administration. The model rats without PTX treatment served as treatment control. The serum levels of Th1 cytokines(interferon-γ, IFN-γ; tumor necrosis factor-α, TNF-α), Th2 cytokines (interleukin-4,IL-4;interleukin-6,IL-6) and type Ⅳ collagen were measured by enzyme-linked immunosorbent assay (ELISA). The expression and distribution of β-catenin in liver tissue and the percentage of area of type Ⅳ collagen accounted in the liver were analyzed by immunohistochemical analyses. The changes in serum cytokines were depicted by using One-way ANOVA, and the correlation between β-catenin expression and cytokines levels or hepatic fibrosis development was elucidated by Bivariate.Results The serum levels of Th2 cytokines in model group were significantly higher than those in treatment group, and even higher than those in control group (F=71. 260,91. 732, all P＜0.05).However, the levels of Th1 cytokines in model group were significantly lower than in treatment group while even lower than those in control group(F= 50. 420,10. 625, all P＜0.05). Serum cytokines came out to be Th2 polarized. Meanwhile, the percentage of type Ⅳ collagen area accounted in the liver,which was corresponding to the degree of liver fibrosis, was lower in the treatment group than the model group and even lower in control group (F=3 000,both P<0.05). β-catenin expression in the liver of model group was stronger than that in the treatment group, and even stronger than that in normal group (F=92. 030, both P＜0. 05). According to β-catenin immunohistochemical analyses based on patho-photos, livers from the model group showed dark color in both cell cytoplasm and nucleus, while the liver from the treatment group only showed weak color in cytoplasm and no straining color in nucleus and the liver from normal group showed colors neither in cytoplasm nor in the nucleus.The expression of β-eatenin had a positive correlation with either the level of Th2 cytokines in serum of rats (r=0. 560,P＜0.01) or the percentage of area of type Ⅳ collagen accounted in the liver of rats (r=0. 757, P＜0. 01). Conclusions Th2 polarization in serum cytokines can aggravate the development of liver fibrosis by inducing the expression of β-catenin, which in the livers of rats is a reflection of the degree of the liver fibrosis.