Mitogen-actived Protein Kinase And Phosphatidylinositol 3-kinase Regulated Hypoxia-inducible Factors-α On Pulmonary Arteries With Hypoxia-induced Pulmonary Hypertension

Objective To study the dynamic levels and correlation relationship of Mitogen-actived protein kinase(MAPK), Phosphatidylinositol 3- kinase(POK), HIFas (HIF-1α,HIF-2α ,HIF-3α) and and HIF-1α'target genes: vascular endothelial growth factor (VEGF) during hypoxic pulmonary hypertension (HPH) development. To investigate the expression of MAPK ,PI3K and HIFs in pulmonary artery of chronic obstructive pulmonary disease (COPD), clarify the roles of MAPK ,PI3K and HIFas in HPH development and provide theoretical basis of mechanisms and remedies for COPD.Methods the study consisted of two parts. 1) models of chronic HPH rats were duplicated by anoxia (respired mixted gases containing 10% O₂, 8 hours per day for 21 days intermittently). After anoxia for 3d, 7d, 14d amd 21d; mean pulmonary artery pressure (mPAP), was measured by right-heart catheterization, right ventricular hypertrophy index (RVHI) was calculated by the ratio of right ventricle to the left ventricle plus septum, and hypoxic pulmonary vascular remodeling (HPSR) was observed with morphmetric analysis by microscope. In situ hybridization, immunohistochemistry and Western blot were used to measure mRNA and protein levels of P-ERK,P-JNK,P-P38,P-AKT,HIFs, and VEGF in pulmonary artery walls and lung tissue respectively. Furthermore, relationship between expression of the genes and mPAP, HPSR, RVHI were analyzed. 2) Small pulmonary arterial remodeling was observed in COPD patients and the control by morphometric analysis. The expression of P-ERK,P-JNK,P-P38,P-AKT and HIFs in lung tissue was examined in COPD patients and the control by in situ hybridization and immunohistochemistry.Results The level of mPAP (23.53±1.78) mm Hg , the ratio of vascular wall thickness to external diameter(WT%) (45.5±3.1) % and the ratio of vascular wall areaResults The level of mPAP (23.53±1.78) mm Hg , the ratio of vascular wall thickness to external diameter(WT%) (45.5±3.1) % and the ratio of vascular wall area to the total area (LA%) [ (54.7±3.2) %] were significantly higher in the hypoxia 7 d group than those in the control group [ (16.15±1.97) mm Hg , (36.8±2.5) % and (63.2±2.5)% respectively] ( P < 0.05) .These parameters reached a high level stable phase on hypoxia 14 d ; RVHI was significantly higher [ (26.9±1.3) %] on hypoxia 14 d than in the control group [ (23.0±1.5) %] ( P < 0.05) .expression of p-ERK protein in control group was poorly positive .but was up-regulated in pulmonary arterial tunica intima and tunica media of all hypoxia rats, expression of p-JNK and p-P38 in control group and hypoxia groupe were poorlypositive. expression of P-AKT protein in control group was poorly positive ,but was up-regulated in pulmonary arterial tunica intima and tunica media ofall hypoxia rats. HIF-1 amRNA staining was poorly positive in control, hypoxia for 3 days and hypoxia for 7 days ,but began to increase significantly after 14-day of hypoxia (0.305±0.104,/><0.05) ,then remained stable. Expression of HIF-laprotein in control group was poorly positive ,but was up-regulated in pulmonary arterial tunica intima of all hypoxic rats. In pulmonary arterial tunica media .the levels of HIF-laprotein was markedly up-regulated after 3-day(0. 209±0.009 , P < 0.05 ) .reaching its peak after 7-day of hypoxia (0.232±0.008,?<0.05) ,then tended to decline after 14-day and 21-day of hypoxia. in pulmonary arterial tunica intima. A significant rise of HIF-2a occurred in pulmonary artery after 7 d of hypoxia respectively, but HIF-3a shov/ed a reversed trend after 14 d of hypoxia. Protein levels of all HIF-a subunits showed a marked increase corresponding to the duration of hypoxia. Expression of VEGF protein began to increase after 7-day of hypoxia (0.188 ±0.018 , P < 0.05) ,reaching its peak after 14-day of hypoxia(0.238 ±0.017 , P < 0.05) ,then remained on the high levell in pulmonary arterial tunica intima. morphometry analysis showed that the ratio of wall area to total area (WA%) and pulmonary artery media thickness (PAMT) increased in the cases of COPD (PO.01). The expression levels of P-ERK,P-AKT ,HIF-la and HIF-2a were significantly higher in pulmonary artery walls of COPD patients than...