Endothelin-1 and eNOS expression in pulmonary aterioles of patients with congenital heart diseases with pulmonary hypertension

AIM: To clarify the role of eNOS and ET-1 in development of pulmonary hypertension (PH) associated with congenital heart diseases. METHODS: 40 patients were randomly divided into three groups: severe or moderate PH group (group A, 12 cases), slight PH group (group B, 14 cases) and normal group (group C, 14 cases). ET-1 and eNOS were examined by using the technique of immunohistochemistry. RESULTS: ① Plasma ET-1 concentration was significantly higher in group A and B than that in group C (P<0.01). Serum NO concentration in group A and B was significantly lower than that in group C (P<0.01). ② The proliferation of medial smooth muscle cells and collagenous fibers of pulmonary arteriole in patients with PH were observed by electron microscopy. ③ ET-1 in pulmonary arteriole was significantly higher in group A and group B than that in group C (P<0.01). eNOS in pulmonary arteriole was significantly lower in group A and group B than that in group C (P<0.01). CONCLUSION: ET-1 and eNOS may play an important role in the pathogenesis of PH.     

Effects of early intervention of adipose-derived mesenchymal stem cells on function of pulmonary arterioles in rats with pulmonary arterial hypertension induced by monocrotaline

AIM：To investigate the effects of early intervention of adipose-derived mesenchymal stem cells (ADMSCs) on the function of pulmonary arterioles in monocrotaline (MCT)-induced pulmonary arterial hypertensive (PAH) rats. METHODS：ADMSCs were obtained from subcutaneous adipose tissue in the rat groin region and isolated by collagenase digestion. Ninety male SD rats were randomly divided into normal control group, PAH group and early intervention of ADMSCs (ADMSCs-EI) group. PAH was induced by MCT at dose of 40 mg/kg intraperitoneally. ADMSCs were delivered via left jugular vein 1 weeks after MCT administration. At the 1st, 2nd and 3rd weeks after transplantation of ADMSCs, mean pulmonary arterial pressure (MPAP) was measured by catheterization. Pulmonary arteriolar endothelium-dependent relaxation (EDdR), endothelium-independent relaxation (EDiR) and vasoconstrictive function (VCF) were evaluated by isolated vascular ring tension. The potency of vascular contraction and relaxation was expressed as the pD2 value. RESULTS：Compared with control group, pulmonary arteriolar EDdR in PAH group was obviously decreased 2 weeks after MCT administration. Meanwhile, compared with PAH group, pulmonary arteriolar EDdR in ADMSCs-EI group was obviously increased 1 week after early transplantation of ADMSCs. Compared with control group, MPAP was significantly increased and pulmonary arteriolar EDdR and EDiR were significantly decreased in PAH group 3 and 4 weeks after MCT administation. Meanwhile, compared with PAH group, MPAP was markedly decreased and pulmonary arteriolar EDdR and EDiR were markedly increased in ADMSCs-EI group 2 and 3 weeks after early transplantation of ADMSCs. However, pulmonary arteriolar VCF was not different among all groups. CONCLUSION：Early intervention of ADMSCs significantly ameliorates the impaired pulmonary arteriolar EDdR and EDiR, and greatly decreases MPAP in MCT-induced PAH rats.     

Baicalein inhibits monocrotaline-induced vascular wall thickening in rats with pulmonary hypertension

AIM:To investigate the effects of baicalein on pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT) in rats, and its molecular mechanism was further explored. METHODS:Male SD rats (n=28) were randomly divided into 4 groups:control group, MCT group, MCT+baicalein 50 mg/kg group and MCT+baicalein 100 mg/kg group. The PAH model was established by subcutaneous injection of MCT. After 2 weeks of modeling, the rats in baicalein treatment groups were gavaged baicalein 50 and 100 mg·kg^-1·d^-1 for 14 d, the rats in control group were administered with saline. After 4 weeks of modeling, right ventricular systolic pressure (RVSP), right ventricular hypertrophy index (RVHI) and right ventricular mass index (RVMI) were detected. Masson staining was used to detect the degree of lung fibrosis. The pathomorphological changes of the pulmonary vessels were observed by HE staining. Western blot was used to detect the expression of α-smooth muscle actin (α-SMA) in the lung tissue and the phosphorylation p38, ERK and JNK in the artery. RESULTS:Compared with the control group, RVSP, RVHI and RVMI increased significantly in the MCT group (P<0.01). Pulmonary fibrosis and the thickening of pulmonary artery wall were observed. α-SMA was up-regulated and p38, ERK and JNK was activated significantly (P<0.01). Compared with the MCT group, baicalein (50 and 100 mg/kg) significantly decreased the RVSP, RVHI and RVMI (P<0.01). Lung fibrosis was reduced and the vascular wall thickening was decreased in baicalein-treated groups. Baicalein (50 and 100 mg/kg) inhibited the phosphorylation of p38, ERK and JNK compared with the MCT group (P<0.01). CONCLUSION:Baicalein ameliorates MCT-induced PAH by the inhibition of pulmonary artery wall thickening at least partially via MAPK signaling pathway.     

Effects of Tian ma gou teng decoction on the serum free calcium concentration and the L-type calcium channels in the vascular smooth muscle cells in spontaneously hypertensive rats

AIM: The research was to investigate the effects of the Tian ma gou teng decoction on the electric physiology feature of L-type calcium channels in the vascular smooth muscle cells in spontaneously hypertensive rats (SHR), and to further explain the mechanism of the Tian ma gou teng decoction in the intervention of blood pressure.METHODS: 12-week-old SHRs were assigned randomly into five groups：group A (treated with Tian ma gou teng decoction), group B (treated with Tian ma gou teng decoction with subtraction concha haliotidis), group C (treated with nifedipine), group D (treated with concha haliotidis), group E (treated with normal saline as control), each group consisted of 9 rats. After treatments were conducted for 4 weeks, the free calcium concentration in serum was measured. The electric physiology feature of L-type calcium channels in the vascular smooth muscle cells was analyzed by patch clamp technique (PCT).RESULTS: No significant difference between group A and group C was observed in the serum free calcium concentration (P>0.05). There were significant differences among group B, group D and group E (P<0.05), compared to before treatment, the change in group E was the most obvious. A decrease in the L-type calcium channel current of vascular smooth muscle cells was observed in group A and group C. The function of group D was feeble, no decrease in the L-type calcium channels current of vascular smooth muscle cells was observed in group B and group E.CONCLUSION: Tian ma gou teng decoction can increase the serum free calcium concentration and block the L-type calcium channel current in vascular smooth muscle cells, indicating one of the mechanism of intervention of blood pressure.     

Chemerin promotes proliferation of mouse vascular smooth muscle cells by up-regulating p-JNK

AIM: To investigate the proliferation property of stable chemerin gene knockdown vascular smooth muscle cells (VSMCs) and to explore its mechanism. METHODS: The normal VSMCs, chemerin gene interfering control VSMCs and stable chemerin gene knockdown VSMCs were divided into normal group, PDGF group, control group and knockdown group. The VSMCs in PDGF group were given platelet-derived growth factor-BB (PDGF-BB) to initiate proli-feration. The cell counting and BrdU assay were employed to investigate the proliferation property of VSMCs. The mitogen-activated protein kinase (MAPK) signal pathway was determined by Western blot. RESULTS: The cell number and BrdU A value in PDGF-BB-treated VSMCs significantly increased as compared with the normal VSMCs(CONCLUSION: Chemerin promotes the proliferation of mouse vascular smooth muscle cells by up-regulating p-JNK production.     

Chronic inhibition of cilazapril on pulmonary vascular and myocardial cell proliferation in hypoxic rats

AIM: To explore the mechanism of cilazapril inhibiting proliferation of pulmonary vascular and myocardial cells in hypoxic rats. METHODS: 30 male Wistar rats were used and divided into three groups: normal control (group A)， intermittent hypoxia for 4 weeks (group B) and intermittent hypoxia for 4 weeks plus cilazapril treatment (group C). The cell proliferation and structural remodeling in pulmonary vasculature and myocardium during hypoxia were studied by biochemical analysis, radioimmunoassay, immunohistochemistry, terminal deoxyuridine tripnosphate nick end labeling and correlated with hemodynamic. RESULTS: (1) The mean pulmonary artery pressure (mPAP) and the right ventricle to left ventricle plus ventricular septum ratio (R/L±S) were significantly higher in the hypoxic rat than that in control animals, while increased thickness of the pulmonary vascular wall and vascular lumen with decrease in the caliber as well as myocardial hypertrophy were observed in hypoxic rats. (2) The proliferative index (PI) of pulmonary arteria and myocardium was significantly higher in group B and C than that in group A. The distribution of ET-1 positive cells was seen in pulmonary arterial wall and cardiomyocytes. The ET-1 immunoreactivity was group B>group C>group A by turns. (3) The concentrations of plasma endothelin-1 (ET-1) and angiotensin converting enzyme (ACE) were significantly higher in group B than that in group A. However, the ET-1 and ACE were significantly lower in group C than those in group B. (4) The ET-1 and ACE had a significant positive correlation with R/L+S, mPAP and PI, respectively. The multivariate linear regression analysis revealed that ET-1 and ACE were major factor affecting PI. CONCLUSION: The pulmonary vascular and myocardial structural remodeling are one of the pathogenesis accompanied with excessive cell proliferation in hypoxic pulmonary hypertension (PH). Cilazapril effectively prevents and treats the hypoxic PH by inhibiting cell proliferation and structural remodeling of pulmonary circulation, as induced by ET-1 and ACE.     

Role of NHE-1 in the proliferation and apoptosis of pulmonary artery smooth muscle cell in rats

AIM: To evaluate the role of Na⁺/H⁺ exchanger-1(NHE-1)in the proliferation and apoptosis of pulmonary artery smooth muscle cells in rats. METHODS: Twenty Wistar rats were equally randomized into the control group and 3-week hypoxic group. Intracellular pH (pHi) of the smooth muscle was determined with fluorescence measurement of the pH-sensitive dye BCECF-AM and the expression of NHE-1 mRNA was detected with RT-PCR. The primary culture of pulmonary artery smooth muscle cell in vitro was performed. In situ cell death detection kit (TUNEL) was used to study the effect of specific NHE-1 inhibitor, dimethyl amiloride (DMA), on the apoptosis of muscle cells which had intracellular acidification. RESULTS: pHi value and expression of NHE-1 mRNA of pulmonary artery smooth muscle cell were significantly higher respectively in the hypoxic group than those in the control group (P＜0.01). DMA elevated the apoptotic ratio significantly. The effect was enhanced when DMA concentration was augmented and the time was prolonged. CONCLUSION: With the function of adjusting pHi, NHE-1 may play an important role in the proliferation and apoptosis of pulmonary artery smooth muscle cells.     

Protective effect of ambroxol against the lung damage in chronically hypoxic rats

AIM: To investigate the effect of ambroxol on pulmonary and vascular injury in chronically hypoxic rats. METHODS: 36 male Wistar rats were randomly divided into 3 groups: normal control,chronically intermittent hypoxia(CIH) and ambroxol precaution group(AP).The CIH and AP groups were made into the chronically hypoxic models.The mean pulmonary artery pressure(PAPM) and the levels of plasma superoxide dismutase(SOD) and plasma nitric oxide(NO),lipid peroxide(LPO) were determined. The levels of the lung homogenates SOD, LPO, NO and the changes in pulmonary vascular structure were also examined. RESULTS: The levels of plasma and lung homogenates SOD,NO in CIH group were respectively significantly lower than that of normal control and AP group( P <0.01),but the levels of plasma and lung homogenates LPO were significantly higher( P< 0.01). PAPM in AP group is significantly lower than that of CIH group( P< 0.01);The damage of pulmonary artery smooth muscle cells and extra cell matrix of AP group is much slighter than that of CIH group. CONCLUSION: Ambroxol might be an effective protector in chronically hypoxic rats.     

Expression of Jagged2/Notch3 signaling molecules in pulmonary hypertensive rats induced by monocrotaline

AIM: To study the expression of Jagged2/Notch3 signaling molecules in pulmonary vascular wall of pulmonary hypertensive rats induced by monocrotaline. METHODS: SD rats were randomly divided into normal control group (C group,n=15), solvent control group (S group,n=15) and monocrotaline model groups (M group,n=15). The model of pulmonary hypertension was established by a single subcutaneous injection of monocrotaline (50 mg/kg). The rats in S group were given a single subcutaneous injection of the same dose of solvent. After 4 weeks, the pulmonary vascular remodeling was assessed by HE staining, and the mean pulmonary artery pressure (mPAP) and right ventricular systolic pressure (RVSP) were determined by right heart catheterization. The expression of Jagged2/Notch3/Hes5 molecules in the pulmonary vascular wall was detected by immunohistochemical method and real-time PCR. RESULTS: Compared with S group and C group, the percentage of medial wall thickness of smaller arteries in model group increased significantly (P<0.01). The levels of mPAP and RVSP in M group were significantly higher than those in S group and C groups (P<0.01). The results of real-time PCR showed that the expression of Jagged2, Notch3 and Hes5 was significantly increased in M group compared with S group and C group. The data from immunohistochemical detection indicated that Jagged2 mainly expressed in the intima of small lung artery, Notch3 and Hes5 mainly expressed in the medial smooth muscle cells. Compared with S group and C group, the expression of Jagged2 and Notch3 was significantly increased in the lung small arteries of M group. CONCLUSION: The activation of Jagged2/Notch3 signaling pathway might play an important role in the formation of pulmonary hypertension.     

Effects of long-term cigarette smoke exposure on pulmonary vascular remodeling and TGF-β1 expression in rat pulmonary vessels

AIM: To observe the effects of long-term cigarette smoke exposure on pulmonary vascular remodeling and the protein expression of transforming growth factor-β1(TGF-β1) in the rats, and to explore the mechanism.METHODS: SD rats(n=36) were randomly divided into control group, 2-week smoke exposure(S-2W) group and 12-week smoke exposure(S-12W) groups. HE staining and α-smooth muscle actin staining were performed to observe the pulmonary vascular remodeling.The protein expression of proliferating cell nuclear antigen(PCNA) and TGF-β1 in the pulmonary arteries was determined by the method of immunohistochemistry. The mRNA expression of TGF-β1 in the pulmonary arteries was evaluated by RT-qPCR.RESULTS: Compared with control group, ratio of pulmonary vessel wall thickness to vessel diameter(WT%) and percentage of muscularized vessels were significantly increased in S-2W group and S-12W group(P<0.01). Significant increases in the protein expression of PCNA and TGF-β1 in smoke exposure groups were observed compared with control group. There was significant difference between 2 model groups(P<0.01). Compared with control group, the mRNA expression of TGF-β1 in pulmonary artery walls obviously increased in smoke exposure groups. There was significantly difference between S-2W and S-12W groups(P<0.05). The mRNA expression of TGF-β1 was positively correlated with pulmonary vascular muscularization, WT% and the protein expression of PCNA. CONCLUSION: Long-term cigarette smoke exposure results in pulmonary artery remodeling in rats. The possible mechanism is that cigarette smoking exposure induces the over-expression of TGF-β1 at mRNA level in pulmonary vessels and promotes the proliferation of pulmonary vascular smooth muscle cells in rats.     

Expression of MMP-2 mRNA and MMP-9 mRNA in pulmonary arterioles ofrats with pulmonary hypertension induced by chronic hypoxia hypercapnia

AIM:To investigate the expression of matrix metalloproteinases(MMPs) in pulmonary arterioles of rats with chronic hypoxia and hypercapnia-induced pulmonary hypertension.METHODS:MMP-2, MMP-9 and MMP-2 mRNA, MMP-9 mRNA were observed in pulmonary arterioles by the techniques of immunohistochemistry and in situ hybridization.RESULTS:①The mean pulmonary artery pressure (mPAP) and weight ratio of right ventricle to left ventricle and septum (RV/LV+S) of hypoxia-hypercapnia groups were higher than those of normal control group (P＜0.01). ②Light microscopy showed that vessel wall and media of pulmonary arterioles were thicker in rats of hypoxia-hypercapnia groups than normal control group. There were vessel smooth muscle cell hypertrophy, vessel cavity straitness in hypoxia-hypercapnia group, but no same performance was found in normal control group. ③The expression of MMP-2, MMP-9 and MMP-2 mRNA, MMP-9 mRNA in pulmonary arterioles were significantly higher in rats of hypoxia-hypercapnia groups than control group (P＜0.01).CONCLUSION:Expression of matrix metalloproteinases in pulmonary arterioles is enhanced by hypoxia hypercapnia. This may be involved in pulmonary vascular remodeling in rats with pulmonary hypertension.     

Effect of safflower injection on expression of COX-2 mRNA and protein in chronic hypoxic hypercapnic rat pulmonary arterioles

AIM:To study the effect of safflower injection on expression of COX-2 mRNA in chronic hypoxic hypercapnic rat pulmonary arterioles.METHODS: Sprague-Dawley rats were randomly divided into normal control group, hypoxic hypercapnic group (B), hypoxic hypercapnia+ safflower injection group (C). The concentration of TXB2 and 6-Keto-PGF1α in plasma and in lung were detected by the technique of radioimmunoassay. COX-2 mRNA was observed in arterioles from rats by the technique of in situ hybridization. RESULTS: ① Mean pulmonary arterial pressure(mPAP), weight ratio of right ventricle (RV) to left ventricle plus septum (LV+S) were much higher in B group than those in control group. No significant difference of mean carotid arterial pressure(mCAP) was observed in three groups. ② The concentration of TXB2 and the ratio of TXB2/6-keto-PGF1α were significantly higher in B group than those in control group. ③ Light microscopy showed that vessel wall area/total area, the density of medial smooth muscle cells and the thickness of medial smooth cell layer were significantly higher in B group than those in control group. Electron microscopy showed proliferation of medial smooth muscle cells and collagenous fibers in pulmonary arterioles in B group. Safflower injection reversed the changes mentioned above. ④ Expression of COX-2 mRNA in pulmonary arterioles was much higher in C group than those in B group. Differences of COX-1 mRNA in pulmonary arterioles were not significant between these two groups.CONCLUSION:Safflower injection increases the expression of COX-2 mRNA in chronic hypoxic hypercapnic rat pulmonary arterioles, indicating an important mechanism that safflower injection inhibits the formation of hypoxic hypercapnia pulmonary hypertension and pulmonary vessel remodeling.     

Pathogenesis of endothelial-mesenchymal transition in pulmonary arterial hypertension

Endothelial-mesenchymal transition (EndMT) is a biological process through which endothelial cells change their endothelial phenotype into a mesenchymal or myofibroblastic phenotype with the expression of mesenchymal markers such as α-smooth muscle actin (α-SMA) and vimentin. When the pulmonary vascular endothelial cells are exposed to hypoxia and inflammatory stimulation, vascular smooth muscle cells in the outer and middle membrane accumulate through EndMT process, leading to pulmonary vascular remodeling and pulmonary arterial hypertension (PAH). Transforming growth factor β (TGF-β)/bone morphogentic protein (BMP) signaling pathways promote EndMT process by bone morphogentic protein receptor 2 (BMPR2) gene mutation which up-regulates high mobility group protein A1 (HMGA1) gene and contributes to protein expression such as Slug and Snail, thus resulting in PAH. In brief, TGF-β/BMP signaling pathways and related regulators play an important role in pulmonary vascular reconstruction and the formation of PAH.     

Effects of PFOA exposure on inflammatory mediators IL-4, IFN-γ and glucocorticoid receptor in asthmatic mice

AIM: To investigate the effects of perfluorooctanoic acid (PFOA) exposure on the changes of asthmatic mouse airway inflammation, inflammatory mediators interleukin-4 (IL-4) and interferon-γ (IFN-γ) in serum, and glucocorticoid receptor (GR) expression in the lung tissue.METHODS: BALB/c mice (n=30) were randomly divided into 5 groups:normal control (C) group, asthma (A) group, asthma+low-dose PFOA (AP10) group, asthma+ mode-rate-dose PFOA (AP50) group and asthma+high-dose PFOA (AP100) group. Asthma model and PFOA exposure model of mice were established according to the grouping. The animals were sacrificed and their lungs were collected for HE staining, transmission electron microscopy, Western blot and immunohistochemical staining. ELISA was applied to detect the levels of IL-4 and IFN-γ in the serum.RESULTS: HE staining of the lungs showed that the asthmatic mice, compared with the normal control mice, had obvious mucus secretion around the airways and infiltration of inflammatory cells around airways and blood vessels, and the effects were much more marked in AP groups. Ultrastructural alteration of the lung tissues in the asthmatic mice were indicated by transmission electron microscopy. Compared with C group, the results of ELISA in A group and AP groups proved that IL-4 in the serum was increased and IFN-γ was decreased significantly (P<0.05). Compare with A group, IL-4 was significantly increased and IFN-γ was decreased in AP100 group (P<0.05), and no difference of those between AP10 group and AP50 group was found. The results of Western blot indicated that GR protein expression in the asthmatic mice were decreased compare with the normal mice (P<0.05), and no difference of that among A group and AP groups was observed. Immunohistochemical staining manifested that GR protein was mainly located in the cytoplasm of bronchial columnar epithelial cells, airway smooth muscle cells and vascular smooth muscle cells.CONCLUSION: Acute airway PFOA exposure in asthmatic mice dose-dependently exacebates lung inflammation by inducing Th2 type immune responses, promotes infiltration of inflammatory cells and mucus secretion around the airways and blood vessels, and destroys the ultrastructure of the lung tissues.     

Alteration of pulmonary vascular structure and gaseous molecules in rats with pulmonary hypertension induced by high pulmonary blood flow

AIM: To examine the alteration of pathologic structure and gaseous molecules in rats with pulmonary hypertension induced by high pulmonary blood flow.METHODS: Aortocaval shunting was produced for 11 weeks in rats, and pulmonary hemodynamics was evaluated.Pulmonary vascular micro- and ultra- structure was also examined.Meanwhile,the concentration of plasma nitric oxide (NO) and carbon monoxide (CO) was measured by spectrophotometry.The expression of endothelial nitric oxide synthase (eNOS) and heme oxygenase-1 (HO-1) in pulmonary arteries was detected by immunohistochemistry.RESULTS: After 11- week aortocaval shunting,pulmonary artery mean pressure was significantly increased.Muscularization of small pulmonary vessels and relative medial thickness and area of pulmonary arteries were obviously increased in shunting rats compared with controls.Ultrastructure of intrapulmonary arteries changed obviously in shunting rats.Meanwhile,plasma NO concentration was increased and eNOS expression in pulmonary artery endothelial cells was significantly augmented in rats of shunting group.Plasma carbon monoxide level and HO-1 expression in puomonary artery smooth muscle cells,however,were not altered in shunting rats.CONCLUSIONS: Pulmonary vascular structural remodeling is the important pathologic basis of pulmonary hypertension induced by a left-to-right shunt,and NO other than CO might play an important regulating role in the development of high pulmonary blood flow-induced pulmonary hypertension.     

Effect of exogenous HGF gene transfection on pulmonary perfusion and pressure in pulmonary artery hypertension in rabbits

AIM: To investigate the feasibility of exogenous hepatocyte growth factor (HGF) gene transfection to promote pulmonary collateral angiogenesis, improve pulmonary perfusion and reduce pulmonary artery pressure in the rabbit model of pulmonary artery hypertension (PAH). METHODS: The model rabbits of PAH were randomly divided into control group, empty vector group and HGF gene transfection group. The rabbits in HGF gene transfection group were transfected with Ad-HGF via intratracheal instillation. Pulmonary hemodynamic indicators were monitored in the 4th week after HGF gene transfection. Density of pulmonary vessels was examined with double-labeling immunofluorescence (endothelial cells were labeled with anti-FⅧ and vascular smooth muscle cells were marked with anti-α-SMA). Double-labeling immunofluorescence of FITC-lectin and anti-α-SMA was also performed to evaluate the pulmonary blood perfusion. RESULTS: Four weeks after transfection, the density of pulmonary arterioles of the rabbits in HGF gene transfection group was higher than that in control group and empty vector group (P<0.05), which was confirmed by double-labeling immunofluorescence. Pulmonary blood perfusion in HGF group was significantly increased compared with that in the other two groups, in which pulmonary arterial stenosis and occlusion were observed. The mean pulmonary artery pressure in HGF transfection group was much lower than that in control group and empty vector group (P<0.05). CONCLUSION: Four weeks after intratracheal adenoviral-mediated HGF gene transfection, pulmonary collateral vessels and pulmonary perfusion increase, and the pulmonary artery pressure is effectively reduced.     

Effect of chronic cigarette smoking on BKCa and Kv1.5 expression in rat pulmonary arterial smooth muscle cells

AIM:To investigate the role of potassium channel expression alteration in chronic cigarette smoking-induced increase in pulmonary vascular responsiveness, the effect of chronic cigarette smoking on large-conductance calcium-activated potassium channel (BK_Ca) and voltage-dependent delayed rectifier potassium channel (Kv1.5) expression in rat pulmonary smooth muscle cells were investigated in vivo. METHODS:HE staining, immuno-histochemistry and in situ hybridization techniques were used. RESULTS: (1) Chronic cigarette smoking downregulates the protein and mRNA expression of BK_Ca in pulmonary arterial smooth muscles. (2) Chronic cigarette smoking downregulated the protein and mRNA expression of Kv1.5 in pulmonary arterial smooth muscles. (3) In big artery, BK_Ca decreased more makedly than Kv1.5, but in small artery, both of them decreased equally. CONCLUSION:Chronic cigarette smoking downregulates the levels of BK_Ca and Kv1.5 in rat pulmonary arterial smooth muscle cells in vivo, which maybe contribute to the mechanism of cigarette smoking-induced increase in pulmonary vascular responsiveness.     

“中国园艺学会第七届青年学术讨论会”

中国园艺学会第九届第8次常务理事扩大会决定，“中国园艺学会第七届青年学术讨论会”由山东农业大学园艺科学与工程学院和山东省园艺学会承办，将于2006年7月或8月在山东泰安举行。     

Ca2+-activated Cl- channels and pulmonary hypertension induced by high pulmonary blood flow

Pulmonary hypertension induced by high pulmonary blood flow involves a variety of complex mechanisms, including endothelial damage, pulmonary artery smooth muscle relaxation-contraction disorder and vascular remodeling. Besides, the factor of ion channels in pulmonary artery smooth muscle cells is also highly correlated to vasoconstriction. In recent years, many studies have shown that activation of Ca²⁺-activated Cl^- channels is responsible for the membrane depolarization of pulmonary artery smooth muscle cells, and plays an important role in the regulation of vascular tone and vasoconstriction. This article reviews the biophysical and pharmacological characteristics of Ca²⁺-activated Cl^- channels as well as the influence of Ca²⁺-activated Cl^- channels in high pulmonary blood flow-induced pulmonary hypertension.     

Effects of She xiang bao xin wan (SXBXW) on phenotype transformation of vascular smooth muscle cells

AIM: To observe the effects of She xiang bao xin wan (SXBXW) of Chinese patent drug on the phenotype transformation of vascular smooth muscle cells.METHODS: The vascular smooth muscle cell line RASMC P8 was used as the cell model in this experiment. The cells were treated with SXBXW at the doses of 0.25 g/L, 0.50 g/L, 1.0 g/L and 2.0 g/L, respectively, and control cells were treated with the same volume of culture medium without SXBXW. The expression of α-smooth muscle actin (α-SMA) and the smooth muscle myosin heavy chain (SM-MHC), which served as specific molecular markers of vascular smooth muscle contraction in RASMC P8 cells, was analyzed by flow cytometry. RESULTS: The percentages of α-SMA and SM-MHC negative cells in SXBXW treated groups were lower than those in control group. Meanwhile, the percentages of α-SMA and SM-MHC positive cells were increased in RASMC P8 cells treated with SXBXW, indicating that SXBXW prompted the transformation of RASMC P8 cells from synthetic to contractile phenotype.CONCLUSION: Chinese patent drug SXBXW plays a role in transforming the cell phenotype from synthetic to the contraction in vascular smooth muscle.