[A study of inhibitory effect of chromogranin A derived peptide CGA(47 _ 66) on hyper - permeability of endothelium induced by serum of septic patient].

OBJECTIVE:To explore the role of chromogranin A ( CGA) derived peptide CGA47~ ( Chromfungin, CHR) on septic serum induced high permeability of vascular endothelial cells. METHODS:Human umbilical venous endothelial cell line (EA.hy926 cells) was exposed to CHR, serum of septic shock patient, and tumor necrosis factor-a (TNF-a) respectively. Methyl thiazolyl tetrazolium (MTT) method, Transwell assay and immunofluorescence were performed to determine cell viability (absorbance (A) value J, permeability of monolayer endothelial cells (A value) , and the morphological characteristic and distribution ofF -actin respectively. RESULTS:Compared with the blank control group, when EA.hy926 were exposed to CHR with 1, 10, 100 nmol/L the cell activity was not significantly affected (A value: 1.219 ± 0.253, 1.179 ± 0.065, 1.179 ± 0.062 vs. 1.306 ± 0.162, all P>0.05), while when the cells was exposed to CHR in 1 000 nmol/L the cell activity was significantly inhibited (A value: 1.049 ± 0.256 vs. 1.306 ± 0.162, t=-2.390, P=0.031 ). Compared with blank control group, when the cells were exposed to CHR of 1, 10, 100 nmol/L a significant decrease in permeability in EA.hy926 cells was observed (A value: 1.619 ± 0.324, 1.496 ± 0.356, 1.132 ± 0.280 vs. 2.315 ± 0.440, P<0.05 or P<0.01 ). Treatment of septic shock patient's serum or TNF-a to EA. hy926 produced an obvious increase in its permeability (septic serum group A value: 1.204 ± 0.248 vs. 0.277 ± 0.017, P<0.01; TNF-a group A value: 2.485 ± 0.113 vs. 1.602 ± 0.679, P<0.05). High-permeability induced by TNF-a or septic shock patient's serum was alleviated hy CHR in the concentration of 1, 10, 100 nmol/L in a dose-dependent manner (septic serum + CHR group A value: 0.299 ± 0.065, 0.224 ± 0.028, 0.131 ± 0.015 vs. 1.204 ± 0.248; TNF -a + CHR group A value: 1.995 ± 0.394, 1.920 ± 0.096, 1.744 ± 0.475 vs. 2.485 ± 0.113, P<0.05 or P<0.01 ). Under a laser scanning confocal microscope, it was found that the F-actin cytoskeleton of EA.hy926 cells was redistributed, and more stress fibers were found in the septic shock patient's serum group and TNF-α group, while CHR obviously alleviated the above effects induced by septic shock patient's serum or TNF-α. CONCLUSION:In a dose-dependent manner, CHR may inhibit increased permeability of vascular endothelial cells induced by septic shock patient's serum, its underlying mechanism may be related to inhibition of the effect of TNF-α.