血管内皮生长因子促多囊肾大鼠胆管上皮细胞活力及胆管囊性扩张的机制研究

目的:探讨血管内皮生长因子(vascular endothelial growth factor, VEGF)促进多囊肾(polycystic kidney, PCK)大鼠胆管上皮细胞活力及胆管囊性扩张的机制。方法:免疫组织化学染色法检测正常和PCK大鼠肝组织中VEGF (n=6)和CD31 (n=10)的表达情况。RT-qPCR法和酶联免疫吸附实验分别检测胆管上皮细胞和培养上清液中的VEGF表达水平。WST-1比色法检测VEGF对大鼠胆管上皮细胞活力和胆管上皮细胞上清液对内皮细胞活力的影响。细胞迁移实验和管腔形成实验检测胆管上皮细胞上清液对大鼠血管内皮细胞迁移和管腔形成能力的影响。结果:免疫组织化学染色结果表明,VEGF在PCK大鼠的胆管上皮细胞中呈高表达;肝汇管区新生微血管数量明显多于正常大鼠(P<0.01);RT-qPCR法和酶联免疫吸附法检测结果表明,PCK大鼠胆管上皮细胞中VEGF mRNA和蛋白表达显著高于正常大鼠(P<0.01);WST-1结果显示,VEGF可增强PCK大鼠胆管上皮细胞活力(P<0.01);PCK大鼠胆管上皮细胞培养上清液能提高内皮细胞活力(P<0.01);VEGF siRNA和VEGF受体抑制剂可降低胆管上皮细胞活力(P<0.01);细胞迁移实验和管腔形成实验结果表明,PCK大鼠胆管上皮细胞培养上清液可提高内皮细胞迁移能力和管腔形成能力(P<0.01)。结论:PCK大鼠的胆管囊性扩张与胆管上皮细胞过度分泌VEGF存在联系。

VEGF promotes biliary epithelial cell viability and cystic dilation in rats with polycystic kidney

AIM: To explore the promoting effect of vascular endothelial growth factor(VEGF) on the viability of biliary epithelial cells and biliary cystic dilation in rats with polycystic kidney(PCK). METHODS: Immunohistoche-mical staining was used to detect the expression of VEGF(n=6) and CD31(n=10) in the liver tissue of normal and PCK rats. RT-qPCR and ELISA were used to evaluate the expression levels of VEGF in rat biliary epithelial cells and culture supernatant. WST-1 assay was applied to measure the effect of VEGF on the viability of rat biliary epithelial cells, and the influence of cholangiocyte culture supernatant on the viability of rat vascular endothelial cells. The cell migration assay was employed to observe the effect of cholangiocyte culture supernatant on endothelial cell migration. Tube formation assay was used to assess the impact of cholangiocyte culture supernatant on the angiogenic ability of endothelial cells. RESULTS: The result of immunohistochemical staining manifested that VEGF was highly expressed in the cholangiocytes of the PCK rats(P<0.01). More newly formed blood vessels were observed in the hepatic portal area of PCK rats than that in normal rats(P<0.01). The results of RT-qPCR and ELISA suggested that the mRNA and protein expression levels of VEGF in the cholangiocytes of PCK rats were significantly higher than those in normal rats(P<0.01). VEGF enhanced the viability of cholangiocytes in PCK rats(P<0.01). The culture supernatant of cholangiocytes in PCK rats increased the endothelial cell viability(P<0.01). VEGF siRNA and VEGF receptor inhibitor reduced the viability of cholangiocytes(P<0.01). The results of cell migration assay and tube formation assay indicated that the abilities of endothelial cell migration and tube formation were improved by the culture supernatant of cholangiocytes in PCK rats(P<0.01). CONCLUSION: The bile duct cystic dilation of PCK rats was related to the excessive secretion of VEGF in bile duct epithelial cells.