AIMTo study human urotensin II (hUII) expression in intrapulmonary arteries of rats with pulmonary hypertension induced by high pulmonary blood flow and explore the role of hU II in the development of pulmonary hypertension induced by left to right shunt.

METHODSAortocaval shunting was produced for 11 weeks in rats. Pulmonary artery mean pressure (PAMP) of each rat was evaluated using right cardiac catheterization. The pulmonary vascular structural changes, including the percentage of muscularized arteries of small pulmonary vessels and relative medial thickness of intra-acinar pulmonary arteries were examined. Meanwhile, the expression of hU II by pulmonary arteries was detected by immunohistochemistry.

RESULTSAfter 11-week aortocaval shunting, PAMP was significantly increased. The percentage of muscularized arteries of small pulmonary vessels and relative medial thickness of pulmonary arteries were obviously increased in shunting rats compared with controls (P < 0.01, respectively). Meanwhile, hU II expression by pulmonary artery endothelial cells and smooth muscle cells was significantly augmented in rats of shunt group, which was positively correlated with PAMP and the structural changes in pulmonary arteries.

CONCLUSIONThe up-regulation of hU II in pulmonary arteries might be involved in the development of pulmonary vascular structural remodeling and pulmonary hypertension induced by high pulmonary blood flow.

Animals ; Humans ; Hypertension, Pulmonary ; metabolism ; Male ; Pulmonary Artery ; metabolism ; physiopathology ; Pulmonary Circulation ; Rats ; Rats, Sprague-Dawley ; Urotensins ; metabolism

OBJECTIVETo investigate the dynamic expression and role of SENP1 (SUMO-specific proteases-1) in the pulmonary vascular wall of rat during the development of hypoxic pulmonary hypertension (HPH).

METHODSForty adult male Wistar rats were randomly divided into 5 groups (n = 8), and exposed to normoxia (Control group) or exposed to hypoxia for 3, 7, 14 or 21 d, respectively. The HPH models were established by normobaric intermittent hypoxia. Mean pulmonary arterial pressure (mPAP), right ventricle hypertrophy index (RVHI), and vessel morphometry were measured. Reverse transcriptase-polymerase chain reaction(RT-PCR) and in situ hybridization were used to determine the mRNA expression of SENP1. Immunohistochemistry and Western blot were used to determine the protein expression of SENP1.

RESULTSThe hypoxic rats developed pulmonary vascular remodeling in pulmonary arterioles after 7 d of hypoxia exposure. Pulmonary vascular remodeling in pulmonary arterioles significantly increased after 14 d of hypoxia. The level of mPAP in hypoxic rats increased significantly after 7 d of hypoxia, reached its peak after 14 d of hypoxic exposure. RVHI was markedly increased after 14 d of hypoxia. In situ hybridization and immunohistochemical analysis showed that SENP1 mRNA and protein were positively stained in control. SENP1 mRNA expression had little changes after exposure to hypoxia compared with the control, however, SENP1 protein expression was declined gradually after 7 d of hypoxia. The results of RT-PCR and Western blot showed that the same dynamic expression of SENP1 mRNA and protein in lung tissues of rats. Linear correlation analysis showed that SENP1 protein were negatively correlated with mPAP, pulmonary vascular remodeling index and RVHI.

CONCLUSIONUnder chronic hypoxia, SENP1 protein can be degradated. The dynamic expression of SENP1 protein may play a role in implicating in the development of HPH.

Animals ; Endopeptidases ; metabolism ; Hypertension, Pulmonary ; etiology ; metabolism ; Hypoxia ; complications ; metabolism ; Male ; Pulmonary Artery ; metabolism ; Rats ; Rats, Wistar

To ascertain whether connective tissue growth factor (CTGF) participates in the remodeling of pulmonary artery at the early-stage of bleomycin (BLM)-induced pulmonary fibrosis, mean pulmonary arterial pressure, the expression of type I and type III collagens, and the expression and location of CTGF in pulmonary artery and arteriole were investigated in the present study. Sprague-Dawley rats received instillation of BLM [5 mg/kg body weight, in 0.5 mL of normal saline (NS)] or instillation of the same amount of NS as control. Mean pulmonary arterial pressure was detected via a catheter in the pulmonary artery. Type I and type III collagens were examined with Sirius red staining under polarized light. CTGF expression was investigated by using immunohistochemistry, and was represented as average optical density and percentage of positive area of CTGF. The mean pulmonary arterial pressure was higher in rats on day 14 after BLM instillation [(19.5+/-2.9) mmHg] than that in the control rats [(14.8+/-1.2) mmHg] (P<0.05). The type I and type III collagens were increased both in pulmonary artery and arteriole of rats on day 14 after BLM instillation, compared with those in the control rats (P<0.05, P<0.01, respectively). The ratio of type I/III collagens in pulmonary artery was also higher in BLM-treated rats than that in the control rats (P<0.05). The values of average optical density of positive CTGF staining were increased both in pulmonary artery (0.37+/-0.02) and arteriole (0.40+/-0.03) of rats on day 14 after BLM instillation, compared with those in the control rats (artery, 0.34+/-0.01; arteriole, 0.29+/-0.01) (both P<0.05). The percentages of positive area of CTGF were higher in pulmonary artery (8.40+/-1.13) and arteriole (12.4+/-2.0) of rats on day 14 after BLM instillation than those in the control rats (artery: 1.42+/-0.63; arteriole: 1.16+/-0.34), respectively (both P<0.05). The increased positive CTGF staining areas were mainly located in the endothelium and smooth muscle layer. It is therefore concluded that CTGF expression increases in the endothelium and smooth muscle layer of pulmonary artery and arterioles during high pulmonary arterial pressure and remodeling of pulmonary artery at the early-stage of BLM-induced pulmonary fibrosis, and that the increased CTGF might be one of the mechanisms of maintenance and development of pulmonary hypertension.
Animals ; Bleomycin ; Collagen Type I ; metabolism ; Collagen Type III ; metabolism ; Connective Tissue Growth Factor ; metabolism ; Hypertension, Pulmonary ; Pulmonary Artery ; metabolism ; Pulmonary Fibrosis ; metabolism ; Rats ; Rats, Sprague-Dawley

AIMTo investigate the dynamic changes and functions of urotensin II (U lI) receptor (UT) in pulmonary arteries of rats chronically exposed to hypoxia-hypercapnia.

METHODSIn rats with hypoxia-hypercapnia at 1, 2 and 4 weeks U II receptor binding of pulmonary arteries sarcolemma was determined by radioligand assay. U II mRNA and UTmRNA in various grades of pulmonary arterioles were measured by in situ hybridization.

RESULTS(1) Mean pulmonary pressure (mPAP) and weight ratio of right ventricle to left ventricle and septum (RV/LV + S) of 1-week group were higher than those of normal control (NC) group by 26.2% and 21.6% (P < 0.01), respectively, and 2-week group higher than 1-week group by 22.5% and 14.1% (respectively, P < 0.01). However, no significant changes were found between 4-week and 2-week group. (2) U Il receptor (Bmax) of 1-week group was higher than NC group by 38.8%, 2-week group higher than 1-week group by 23.2%, and 4-week group increased 7.3% compared with 2-week group (respectively, P < 0.01). The UT changes were time-dependent, while the affinity to U II (Kd) was no different among each group. (3) UII mRNA in each grade of pulmonary arterioles of 2-week group and 4-week group were higher than NC group (respectively, P < 0.01), and those of 2-week group were higher than 1-week group by 5.9% (P > 0.05), 16.4% and 9.1% (respectively, P < 0.01), while no differences existed between 2-week group and 4-week group. (4) UT mRNA in each grade of pulmonary arterioles of all hypoxia-hypercapnia groups was higher than NC group (respectively, P < 0.01), and those of two abaxial grade vessels in 1-week group were the highest. No differences existed between 2-week group and 4-week group. (5) The pulmonary vessels remodeling were time-dependently aggravated by hypoxia-hypercapnia.

CONCLUSIONThe dynamic changes of UT in pulmonary arterioles might have important contribution to the development of pulmonary hypertension and pulmonary arteriole remodeling induced by chronic hypoxia-hypercapnia in rats.

Animals ; Arterioles ; metabolism ; physiopathology ; Hypercapnia ; metabolism ; Hypertension, Pulmonary ; metabolism ; physiopathology ; Hypoxia ; metabolism ; Male ; Pulmonary Artery ; metabolism ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled ; metabolism

OBJECTIVE: To investigate the role of myelin and lymphocyte protein (MAL) in pulmonary hypertension (PAH). METHODS: Blood samples were collected from 50 patients with PAH (PAH group) and 50 healthy individuals for detection of plasma MAL expression using ELISA.According to the echocardiographic findings, the patients were divided into moderate/severe group (n=18) and mild group (n=32), and the correlation between MAL protein level and the severity of PAH was analyzed.In a pulmonary artery smooth muscle cell model of PAH with hypoxia-induced abnormal proliferation, the effects of mal gene knockdown and overexpression on cell growth, proliferation and starvation-induced apoptosis were observed; the changes in NK-κB signaling pathway in the transfected cells were detected to explore the molecular mechanism by which MAL regulates PAMSC proliferation and apoptosis. RESULTS: The plasma level of MAL was significantly higher in patients with PAH than in healthy individuals (P < 0.05), and the patients with moderate/severe PAH had significantly higher MAL level than those with mild PAH (P < 0.001).In PAMSCs, exposure to hypoxia significantly increased the mRNA and protein expression levels of MAL (P < 0.05), and MAL knockdown obviously inhibited hypoxia-induced proliferation and promoted starvation-induced apoptosis of the PAMSCs (P < 0.05).Knocking down mal significantly inhibited the activation of NK-κB signaling pathway that participated in regulation of PAMSC proliferation (P < 0.05). CONCLUSION The plasma level of MAL is elevated in PAH patients in positive correlation with the disease severity.MAL knockdown inhibits abnormal proliferation and promotes apoptosis of PAMSCs by targeted inhibition of the NF-κB signaling pathway to improve vascular remodeling in PAH.
Humans ; Pulmonary Artery ; Hypertension, Pulmonary ; Myelin Sheath/metabolism* ; Apoptosis ; Myocytes, Smooth Muscle ; Vascular Remodeling/genetics* ; Cell Proliferation ; Hypoxia/metabolism* ; Lymphocytes

Humans ; Ion Channels ; Myocytes, Smooth Muscle ; metabolism ; physiology ; Pulmonary Artery ; metabolism ; physiology

OBJECTIVETo investigate the effect of heat shock protein 70 (HSP70) on pulmonary arterial pressure and pulmonary vascular remodeling in neonatal rats with hypoxic pulmonary hypertension (HPH).

METHODSA total of 128 Wistar neonatal rats were randomly divided into HPH model and blank control groups. According to the transfection solution, the HPH model group was further divided into normal saline group, empty virus group (viral vectors marked with a green fluorescent signal and not carrying the target gene), and virus+HSP70 group (viral vectors marked with a green fluorescent signal and carrying the target gene). The HPH model was established by inhalation of nitrogen-oxygen mixture (1.5 L/minutes and 8% oxygen). Pulmonary arterial pressure (mPAP) and the indicators of pulmonary vascular remodeling (MT% and MA%) were measured on days 3, 7, 10, and 14 of hypoxia.

RESULTSOn days 3, 7, and 10 of hypoxia, the normal saline and empty virus groups had significantly enhanced expression of HSP70 compared with the blank control group (P<0.01), and the virus+HSP70 group had significantly higher expression of HSP70 than the blank control, normal saline, and empty virus groups (P<0.01). On day 14 of hypoxia, the expression of HSP70 showed no significant difference between these groups (P>0.05). On days 3, 7, and 10 of hypoxia, the normal saline and empty virus groups showed continuous increases in mPAP compared with the blank control group (P<0.05). There was no significant difference in mPAP between the virus+HSP70 and blank control groups (P>0.05). On day 14 of hypoxia, there was no significant difference in mPAP among three subgroups of the HPH model group (P>0.05), but the mPAP in the three subgroups was significantly higher than in the blank control group (P<0.05). After 7 days of hypoxia, the normal saline and empty virus groups showed significantly higher MT% and MA% than the blank control group (P<0.05), but the two indicators showed no significant differences between the virus+HSP70 and the blank control groups (P>0.05). On day 14 of hypoxia, there were no significant differences in MT% and MA% among three subgroups of the HPH model group (P>0.05), but the MT% and MA% in the three subgroups were higher than in the blank control group (P<0.05).

CONCLUSIONSHSP70 may reduce pulmonary arterial pressure and pulmonary vascular remodeling in neonatal rats with HPH.

Animals ; HSP70 Heat-Shock Proteins ; genetics ; metabolism ; Humans ; Hypertension, Pulmonary ; cerebrospinal fluid ; metabolism ; physiopathology ; Hypoxia ; genetics ; metabolism ; physiopathology ; Oxygen ; metabolism ; Pulmonary Artery ; metabolism ; Rats ; Rats, Wistar ; Vascular Remodeling

OBJECTIVETo investigate the electrophysiological changes of voltage-gate potassium channel (Kv) of pulmonary arterial smooth muscle cells of pulmonary arterial hypertension in rats induced by left to right shunt, and to analyze the role of Kv during the progress of pulmonary arterial hypertension.

METHODSForty male SD rats were randomly divided into three groups, group A (control, n = 10), group B (sham operated only group, n = 10), and group C (PAH model group, n = 20). Mean pulmonary artery pressure (mPAP) and right ventricular hypertrophy index (RVHI) of each rat were measured, single pulmonary artery smooth muscle cell (PASMC) was obtained by acute enzyme separation method (collagenase I plus papain) and the conventional whole-cell patch clamp technique was used to record resting membrane potential (Em), potassium ion current of voltage-gated potassium channel, the I-V curve between each 2 groups was compared, and correlation of each parameter was analyzed.

RESULT(1) The mPAP and RVHI of group C were significantly higher than those of group A and group B (P < 0.01, respectively). (2) The Em of group C [(-33.00 ± 4.09) mV] was significantly higher than that of group A [(-48.10 ± 4.54) mV] and group B [(-51.11 ± 3.66) mV], P < 0.01. (3) The peak current at +50 mV of voltage-gated potassium channel: in group C [(64.80 ± 8.40) pA/pF], it was significantly lower than that of group A [(120.85 ± 11.66) pA/pF] and group B [(118.03 ± 10.18) pA/pF] (P < 0.01, respectively). None of the parameters showed any significant difference between group A and group B (P > 0.05 for all comparisons). (4) Compared with group A and group B, the I-V curve of group C significantly downward shifted (P < 0.01, respectively). The difference in I-V curve between group A and group B was not significant, P > 0.05. (5) The correlation of resting membrane potential and mPAP and RVHI had significantly positive correlation (P < 0.001, respectively); but the correlation of membrane current, membrane current density and mPAP, RVHI and resting membrane potential had significantly negative correlation (P < 0.001, respectively).

CONCLUSIONDuring the formation process of left-to-right shunt induced pulmonary arterial hypertension, function of Kv channel was inhibited, suggesting that Kv channel may be the mechanism of pulmonary arterial hypertension induced by left-to-right shunting.

Animals ; Hypertension, Pulmonary ; metabolism ; physiopathology ; Male ; Muscle, Smooth, Vascular ; metabolism ; Patch-Clamp Techniques ; Potassium ; metabolism ; Potassium Channels, Voltage-Gated ; metabolism ; Pulmonary Artery ; metabolism ; physiopathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the impact of sulfur dioxide (SO(2)) on hydrogen sulfide (H(2)S)/cystathionine-γ-lyase (CSE) and H(2)S/mercaptopyruvate sulfurtransferase (MPST) pathways in the pathogenesis of hypoxic pulmonary hypertension.

METHODSThirty-two male Wistar rats were randomly divided into four groups: control group (n = 8), hypoxic group (n = 8), hypoxic + SO(2) group (n = 8) and hypoxic + hydroxamate (HDX) group (n = 8). After 21 days of experiment, the concentration and production of H(2)S in lung tissues were measured respectively for each rat. The protein expression of CSE and MPST in intima and media of small pulmonary arteries in rats was detected with immunohistochemical method.

RESULTSCompared with control group, the mean pulmonary artery pressure (mPAP) in rats of hypoxic group was increased significantly [(33.38 ± 6.32) mm Hg vs. (16.74 ± 3.81) mm Hg, P < 0.01]. Compared with hypoxic group, the mPAP in rats of hypoxic + SO(2) group was decreased significantly [(29.65 ± 2.53) mm Hg vs. (33.38 ± 6.32) mm Hg, P < 0.01]. However, compared with hypoxic group, the mPAP in rats of hypoxic + HDX group was increased significantly [(39.44 ± 6.26) mm Hg vs. (33.38 ± 6.32) mm Hg, P < 0.01]. Compared with control group, the concentration [(2.02 ± 0.43) µmol/g vs. (3.11 ± 0.42) µmol/g, P < 0.01] and production [(19.64 ± 3.48) nmol/(g·min)vs. (28.20 ± 5.95) nmol/(g·min), P < 0.05] of H(2)S were decreased significantly in rats of hypoxic group, respectively. When treated with SO(2), hypoxic rats showed an increased concentration [(2.73 ± 0.20) µmol/g vs. (2.02 ± 0.43) µmol/g, P < 0.01] and production [(26.24 ± 1.92) nmol/(g·min) vs. (19.64 ± 3.48) nmol/(g·min), P < 0.01] of H(2)S in lung tissue compared with those without receiving SO(2) treatment. When treated with HDX, hypoxic rats showed a significant decrease in concentration [(1.64 ± 0.23) µmol/g vs. (2.02 ± 0.43) µmol/g, P < 0.05] and production [(13.94 ± 3.63) nmol/(g·min) vs. (19.64 ± 3.48) nmol/(g·min), P < 0.05] of H(2)S in lung tissue compared with those without receiving HDX treatment. As for the expression of CSE in small pulmonary arteries (SPAs), compared with control group, the expression of CSE in intima [(0.31 ± 0.02) vs. (0.36 ± 0.01), P < 0.01] and media [(0.27 ± 0.01) vs. (0.30 ± 0.01), P < 0.01] in rats of hypoxic group was decreased significantly. While compared with hypoxic group, the expression of CSE in intima [(0.35 ± 0.02) vs. (0.31 ± 0.02), P < 0.01] in SPAs of hypoxic + SO(2) group was increased significantly. With HDX treatment, the expression of CSE in intima [(0.26 ± 0.01) vs. (0.31 ± 0.02), P < 0.01] in SPAs of hypoxic group was lower than that without HDX treatment. As for the expression of MPST in SPAs, compared with hypoxic group, the expression of MPST in media [(0.32 ± 0.02) vs. (0.29 ± 0.01), P < 0.01] in SPAs of hypoxic + SO(2) group was increased significantly.

CONCLUSIONSO(2) might upregulate H(2)S/CSE and H(2)S/MPST pathways in pulmonary arteries of hypoxic rats.

Animals ; Cystathionine gamma-Lyase ; metabolism ; Hydrogen Sulfide ; metabolism ; Hypertension, Pulmonary ; enzymology ; physiopathology ; Hypoxia ; metabolism ; physiopathology ; Male ; Pulmonary Artery ; metabolism ; physiopathology ; Rats ; Rats, Wistar ; Sulfur Dioxide ; pharmacology ; Sulfurtransferases ; metabolism

AIMTo investigate the expression of heme oxygenase-1 gene and production of endogenous carbon monoxide in the rat lung tissue at different time points of chronic hypoxic pulmonary hypertension and the effect of hemin, an inducer of heme oxygenase, on the expression of HO-1 gene and production of endogenous carbon monoxide and pulmonary hypertension.

METHODSWe recreated a rat model of hypoxic pulmonary hypertension by intermittent normal pressure hypoxia (10% O2). The following assays were carried out: Reverse transcriptase polymerase chain reaction (RT-PCR) were performed to determine the level of HO-1 mRNA in rat lung tissue, double wave length spectrophotometry was used to evaluate the quantity of COHb in arterial blood, cardiac catheterization was used to measure the right ventricular systolic pressure (RVSP) and HE staining was performed in dissected lung tissue to observe the pathologic changes of the intra-acinar pulmonary arteries(IAPA).

RESULTS(DT here was low level of HO-1 mRNA in normal rat lung tissue, but the level of HO-1 mRNA increased by 2-4 times in the lung tissue of hypoxic rats (P < 0.01). The quantity of COHb was 2-3 times as those of control group (P < 0.01 or P < 0.05). These were accompanied by the increase of RVSP and the thickness of IAPA. (2) Hemin could maintain the HO-1 mRNA and COHb in the hypoxic rat lung tissue at a high level, and partially suppressed the increase of rat RVSP, ameliorated the pathologic changes of IAPA.

CONCLUSIONThe upregulation of the expression of HO-1 gene and production of CO in the rat lung of hypoxic pulmonary hypertension plays a role of inhibition in the development of hypoxic pulmonary hypertension. Hemin has a therapeutic effect on hypoxic pulmonary hypertension.

Animals ; Carbon Monoxide ; metabolism ; Heme Oxygenase (Decyclizing) ; metabolism ; Hemin ; pharmacology ; Hypertension, Pulmonary ; metabolism ; pathology ; physiopathology ; Hypoxia ; metabolism ; pathology ; Male ; Pulmonary Artery ; metabolism ; physiopathology ; Rats ; Rats, Wistar