Background Cyanotic patients have potential growth retardation and malnutrition due to hypoxemia and other reasons. Ghrelin is a novel endogenous growth hormone secretagogue that has effects on growth and cardiovascular activities. The aim of this study was to evaluate the plasma level and myocardial expression of ghrelin and insulin-like growth factor-1 （IGF-1） using an immature piglet model of chronic cyanotic congenital heart defects with decreased pulmonary blood flow. Methods Twelve weanling Chinese piglets underwent procedures of main pulmonary artery-left atrium shunt with pulmonary artery banding or sham operation as control. Four weeks later, hemodynamic parameters were measured. Enzyme-linked immunosorbent assay for plasma ghrelin and IGF-1 level measurement were performed. Ventricular ghrelin and IGF-1 mRNA expressions were measured by quantitative real-time polymerase chain reaction. Results Four weeks after surgical procedure, the cyanotic model produced lower arterial oxygen tension （（68.73±15.09） mmHg）, arterial oxygen saturation （（82.35±8.63）%）, and higher arterial carbon dioxide tension （（51.83±6.12） mmHg）, hematocrit （（42.67±3.83）%） and hemoglobin concentration （（138.17±16.73） g/L） than the control piglets （（194.08±98.79） mmHg, （96.43±7.91）%, （36.9±4.73） mmHg, （31.17±3.71）%, （109.83±13.75） g/L） （all P 〈0.05）. Plasma ghrelin level was significantly higher in the cyanotic model group in comparison to the control （P=0.004）, and the plasma IGF-1 level was significantly lower than control （P=0.030）. Compared with control animals, the expression of ghrelin mRNAs in the ventricular myocardium was significantly decreased in the cyanotic model group （P=0.000）, and the expression of IGF-1 mRNAs was elevated （P=0.001）. Conclusions Chronic cyanotic congenital heart defects model was successfully established. Plasma ghrelin level and myocardial IGF-1 mRNA expression were significantly up-regulated, while plasm
WANG Dong LIU Ying-long LU Xiao-dong ZHU Yao-bin LING Feng LIU Ai-jun LI Gang XU Yu-lin
Background RhoA/ Rho kinase （ROCK） pathway is involved in pulmonary arterial hypertension （PAH） and pulmonary artery smooth muscle cell （PASMC） proliferation. Inhibition of ROCK has been proposed as a treatment for PAH. But the mechanism of RhoA/ROCK pathway and its downstream signaling in proliferation of human PASMCs is unclear. We investigated the effect of fasudil, a selective ROCK inhibitor, on platelet-derived growth factor （PDGF） induced human PASMC proliferation, and the possible association between RhoA/ROCK and extracellular signal-regulated kinase （ERK）,p27KiP1.Methods Human PASMCs were cultured with the stimulation of 10 ng/ml PDGF, and different concentrations of fasudil were added before the addition of mitogen. Cell viability and cell cycle were determined with MTT and flow cytometry respectively. ROCK activity, ERK activity and protein expression of proliferating cell nuclear angigen （PCNA） and p27Kip1 were measured by immunoblotting.Results By MTT assay, PDGF significantly increased the OD value that represented human PASMC proliferation, and pretreatment with fasudil significantly reversed this effect in a dose-dependent manner. After PDGF stimulation, the percentage of cells in S phase increased dramatically from 15.6% to 24.3%, while the percentage in G0/G1 phase was reduced from 80.6% to 59%. And pretreatment with fasudil reversed the cell cycle effect of PDGF significantly in a dose-dependent manner. PDGF markedly induced ROCK activity and ERK activity with a peak at 15 minutes, which were significantly inhibited by fasudil. In addition, fasudil significantly inhibited PDGF-induced PCNA expression and fasudil also upregulated p27Kip1 expression in human PASMCs, which decreased after PDGF stimulation.Conclusion RhoA/ROCK is vital for PDFG-induced human PASMC proliferation, and fasudil effectively inhibited PDGF-induced human PASMC proliferation by up-regulation of p27Kip1, which may be associated with inhibition of ERK activity.
LIU Ai-jun LING Feng WANG Dong WANG Qiang LU Xiao-dong LIU Ying-long
