内毒素受体在肝星状细胞的表达及其作用

目的了解内毒素受体在肝星状细胞活化中的变化和作用。方法分离正常大鼠的肝星状细胞，以逆转录聚合酶链反应法检测其在体外培养过程中内毒素受体（CD14和TLR4）mRNA的表达变化。以细胞免疫染色法检测肝星状细胞内毒素受体CD14的表达。制作肝纤维化和肝硬化的大鼠模型，免疫组织化学法动态检测肝组织内CD14和α平滑肌肌动蛋白的表达变化和定位。结果初分离的肝星状细胞表达低水平的CD14 mRNA，不表达TLR4 mRNA，培养活化的肝星状细胞内毒素受体的表达增强，内毒素可上调这种表达。体外培养10d的肝星状细胞表达CD14蛋白，内毒素作用后CD14表达更明显。在肝纤维化的发展过程中，肝组织内CD14阳性细胞增多，阳性细胞多分布于肝窦周围，晚期CD14阳性细胞聚集在纤维隔内，与α平滑肌肌动蛋白阳性细胞的分布一致。结论肝星状细胞在体内外的活化过程中内毒素受体的表达增强，因此，内毒素受体可能参与肝星状细胞在肝脏炎症和纤维化中的作用。

Expression of endotoxin receptors on hepatic stellate cells during their activation

OBJECTIVE: To investigate the role of endotoxin receptor expression in the activation of hepatic stellate cells (HSCs). METHODS: HSCs were isolated from normal rats and the expression of endotoxin receptors on quiet HSCs and in vitro activated HSCs was determined using RT-PCR and immunocytochemical staining methods. A rat model of liver fibrosis and cirrhosis was established. The expressions of CD14 and alpha-SMA in liver tissues were detected by immunohistochemical staining. RESULTS: Freshly isolated HSCs had a low level of CD14 mRNA expression and no expression of TLR4 mRNA was detected. The in vitro activated HSCs had increased expressions of CD14 mRNA and TLR4 mRNA and LPS up-regulated the expression of endotoxin receptors. Immunocytochemical staining showed cytoplasmic and nucleolus staining for CD14 in the cultured HSCs. LPS played a further role on CD14 protein expression. In the development of liver fibrosis, the number of CD14-positive cells in the livers was increased and these cells were distributed along the sinusoids. In the later stage of liver fibrosis, the CD14-positive cells were gathered in the fibrotic septae, which also contained alpha-SMA positive cells. CONCLUSION: The activated HSCs expressed endotoxin receptors. The endotoxin receptors may be involved in the role in which HSCs played in the inflammatory process and liver fibrosis development.