The regulatory effect of norepinephrine on connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF) expression in cultured cardiac fibroblasts

Abstract

BackgroundConnective tissue growth factor (CTGF) and vascular endothelial cell growth factor (VEGF) have been implicated as important effectors during cardiac remodeling. This study tested the hypothesis that norepinephrine (NE) induces CTGF and VEGF gene and protein expression in cardiac fibroblasts (CF) and the CTGF/VEGF complex will have an effect on angiogenesis. Methods and resultsRats CF were cultured in NE (0.01 to 100μM) for 24h. CTGF and VEGF gene expression were measured by quantitative-PCR. CTGF protein and CTGF/VEGF complex were detected by Western blot. The effect of CTGF/VEGF complex on angiogenesis was detected by endothelial cell tube formation assay. VEGF antigen level, reactive oxygen species (ROS) production were measured by ELISA and DCFH-DiOxyQ assay respectively. NE at 0.01μM up-regulated CTGF mRNA and secretory protein expression significantly whereas at 100μM both gene and protein were down-regulated significantly when compared with controls. At 0.01 to 0.1μM of NE, there was no change in VEGF gene and protein level. NE at 100μM increased VEGF gene and antigen level and ROS production significantly when compared with controls. CTGF/VEGF complex was found to inhibit the angiogenesis of endothelial cells. ConclusionsNE regulates CTGF and VEGF expression in a dose-dependent manner and via VEGF can induce angiogenesis. This work suggests NE may have an important role in ventricular remodeling.