Effect of heparin,IGFBP-4 and IGF-1 on glucose metabolism and function in fibroblasts

AIM:To study the inhibitory effect of IGF binding protein-4 (IGFBP-4), especially in corporation with heparin on the pathopoiesis of insulin-like growth factor-1 (IGF-1) in alveolitis and fibrosis. METHODS:The diploid human embryonic lung (HEL) fibroblasts were incubated respectively with control, 100 μg/L IGF-1, 100 μg/L IGF-1+100 μg/L IGFBP-4, 100 μg/L IGF-1+200 μg/L IGFBP-4, 100 μg/L IGF-1+100 μg/L IGFBP-4+100 μg/L heparin, 100 μg/L IGF-1 + 100 μg/L IGFBP-4+200 μg/L heparin, 100 μg/L IGF-1+100 μg/L heparin, 100 μg/L IGF-1+200 μg/L heparin for 24 h. Then the content of glucose transporter-4 (GLUT-4), hexokinase-2 (HK-2), collagen-4 and elastin were detected, respectively. RESULTS:Compared with control group, HK-2, GLUT-4, elastin and collagen-4 expressed in IGF-1 group were increased obviously. The expression in the group of IGFBP-4 plus IGF-1 was more than that in IGF-1 group. However, all expression was depressed strikingly when heparin was added. CONCLUSION:(1) IGF-1 apparently stimulates HK-2, GLUT-4, elastin and collagen-IV secretions from lung fibroblasts. (2) The intact IGFBP-4 associated with heparin can inhibit the pathopoiesis of IGF-1.