干扰素α-2a与肝纤维化大鼠肝星状细胞的凋亡

Interferon alpha-2a and apoptosis of hepatic stellate cells in rats with hepatic fibrosis

背景:干扰素α-2a改善肝纤维化的机制直到目前仍尚未阐明。目的:进一步验证干扰素α-2a对CCl4诱导大鼠肝纤维化模型中肝星状细胞凋亡的影响。方法:建立CCl4诱导肝纤维化模型,健康SD雌性大鼠50只,采用随机对照原则将SD大鼠分成5组,即生理盐水对照组、纤维化模型组、6×104U/kg干扰素α-2a干预组、12×104U/kg干扰素α-2a干预组及6×104U/kg干扰素α-2a对照组。造模8周时取肝组织标本,分别进行肝纤维化指标检测;RT-PCR分析肝组织bcl-2、bax的表达;免疫组织化学染色用a平滑肌肌动蛋白对活化的肝星状细胞进行标记。结果与结论:肝组织病理形态显示CCl4诱导肝纤维化成功建立,表现为纤维化模型组汇管区周围纤维化明显,有芒状纤维和纤维间隔形成,各干扰素α-2a干预组肝纤维化有不同程度缓解。纤维化模型组有大量a平滑肌肌动蛋白阳性表达,6×104U/kg干扰素α-2a干预组a平滑肌肌动蛋白阳性表达较纤维化模型组减少,12×104U/kg干扰素α-2a干预组更少,6×104U/kg干扰素α-2a对照组未见a平滑肌肌动蛋白阳性表达。结果提示干扰素α-2a能下调CCl4诱导肝纤维化bcl-2的表达,及上调bax的表达。提示干扰素α-2a阻断CCl4诱导肝纤维化机制存在通过调节bcl-2、bax的表达,诱导肝星状细胞凋亡途径,该调节作用可能与干扰素α-2a剂量相关。

BACKGROUND： Up to now, the mechanism underlying interferon alpha 2a to improve hepatic fibrosis has not been clarified. OBJECTIVE： To investigate the effect of interferon alpha 2a on hepatic stellate cells apoptosis in the CC14-induced hepatic fibrosis rat model. METHODS： We established the CC14-induced hepatic fibrosis models in rats. Fifty healthy female Sprague-Dawley rats were equally and randomly divided into five groups, certainly each group included 10 Five groups were saline control group, hepatic fibrosis model group （model group）, 6×10^4 U/kg interferon alpha 2a intervention group, 12×10^4 U/kg interferon alpha 2a intervention group and 6×10^4 U/kg interferonalpha 2a control group. At 8 weeks after modeling, blood and liver tissues were collected to detect the indicators of hepatic fibrosis; the expression of bcl-2 and bax in the liver tissue was analyzed with semi-quantitative reverse transcription-PCR; and immunohistochemical staining was used to mark a-smooth muscle actin in activated hepatic stellate cells. RESULTS AND CONCLUSION： Pathological morphology of the liver tissue demonstrated that the hepatic fibrosis model was successfully established. The model group had fibrosis significantly around the portal area; in addition, Mans-like fibers and fibrous septa formed. Different interferon alpha 2a intervention groups had fibrosis relief to different extent, a-smooth muscle actin had a great amount of positive expression in the model group, while the positive expression of a-smooth muscle actin was lower in the interferon alpha 2a intervention groups, especially in the 12×10^4 U/kg interferon alpha 2a intervention group as compared the model group. In addition, there was no expression of a-smooth muscle actin in the 6× 10^4 U/kg interferon alpha 2a control group. Interferon alpha 2a could down-regulate bcl-2 expression and up-regulate bax expression in CC14-induced hepatic fibrosis models. These findings indicate that the mechanism of interferon alpha 2a blocking CC14-induced hepatic fibrosis is mainly present by regulating the expression of bcl-2 and bax to induce apoptosis of hepatic stellate cells, and this regulatory role is possibly related to interferon alpha 2a dose.