Pulmonary Arterial Remodeling In Rats Research Articles

4-Terpineol attenuates pulmonary vascular remodeling via suppressing PI3K/Akt signaling pathway in hypoxia-induced pulmonary hypertension rats

The hyperproliferation of pulmonary arterial smooth muscle cells (PASMCs) plays a pivotal role in pulmonary arterial remodeling (PAR) of hypoxia-induced pulmonary hypertension (HPH). 4-Terpineol is a constituent of Myristic fragrant volatile oil in Santan Sumtang. Our previous study found that Myristic fragrant volatile oil alleviated PAR in HPH rats. However, the effect and pharmacological mechanism of 4-terpineol in HPH rats remain unexplored. Male Sprague-Dawley rats were exposed to hypobaric hypoxia chamber (simulated altitudes of 4500 m) for 4 weeks to establish an HPH model in this study. During this period, rats were intragastrically administrated with 4-terpineol or sildenafil. After that, hemodynamic indexes and histopathological changes were assessed. Moreover, a hypoxia-induced cellular proliferative model was established by exposing PASMCs to 3% O2. PASMCs were pretreated with 4-terpineol or LY294002 to explore whether 4-terpineol targeted PI3K/Akt signaling pathway. The PI3K/Akt-related proteins expression was also accessed in lung tissues of HPH rats. We found that 4-terpineol attenuated mPAP and PAR in HPH rats. Then, cellular experiments showed 4-terpineol inhibited hypoxia-induced PASMCs proliferation via down-regulating PI3K/Akt expression. Furthermore, 4-terpineol decreased the p-Akt, p-p38, and p-GSK-3β protein expression, as well as reduced the PCNA, CDK4, Bcl-2 and Cyclin D1 protein levels, while increasing levels of cleaved caspase 3, Bax, and p27kip1in lung tissues of HPH rats. Our results suggested that 4-terpineol mitigated PAR in HPH rats by inhibiting the proliferation and inducing apoptosis of PASMCs through suppression of the PI3K/Akt-related signaling pathway.

Paradoxically reduced pulmonary vascular resistance and abnormal vascular remodeling in the obese spontaneously hypertensive heart failure ZSF1 rats

Pulmonary arterial dysfunction and remodeling often develop secondary to left heart disease and systemic hypertension. Excessive body weight is a well-established independent risk factor for the development of cardiovascular disease. However, data have emerged that for heart failure associated pulmonary complications obesity displays a lower long-term mortality. The impact of obesity on hypertension-related heart failure in affecting pulmonary vascular changes is incompletely understood. Here, we examined pulmonary vascular resistance and pulmonary artery function and remodeling in obese diabetic Zucker fatty/spontaneously hypertensive heart failure F1 hybrid (ZSF1) rats. 20-week-old male obese ZSF1 rats display increased left ventricle (LV) hypertrophy and diastolic dysfunction, when compared to age-matched lean spontaneously hypertensive heart failure (SHHR). Pulmonary vascular resistance, pulmonary arterial function and vascular wall remodeling were examined in isolated and perfused, ventilated lung preparations and isolated small pulmonary artery pressure and wire myography, respectively. We found that the pulmonary vascular resistance (normalized to lung weight) was significantly reduced in obese ZSF1 rats compared to SHHR (ZSF1: 0.2±0.02 mmHg·mL -1 ·min·g-1 vs SHHR: 0.29±0.018 mmHg·mL -1 ·min·g-1, p=0.01). In isolated pulmonary arteries the acetylcholine-induced relaxation was maintained, whereas the nitric oxide donor, sodium nitroprusside-induced relaxation was reduced in obese ZSF1 rats (SNP -log(IC50) ZSF1: 4.185±0.166 vs SHHR: 4.96±0.136, p=0.005). The wall thickness and wall-to-lumen ratio of pulmonary arteries were higher in the obese ZSF1 rats when compared to SHHR. Collectively, we found that obesity is associated with a reduced pulmonary vascular resistance and abnormal pulmonary artery remodeling in rats with systemic hypertension and diastolic heart failure, which may have implications in the clinically observed obesity paradox. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Transplantation of viable mitochondria improves right ventricular performance and pulmonary artery remodeling in rats with pulmonary arterial hypertension

ObjectiveBecause mitochondrial dysfunction is a key factor in the progression of pulmonary hypertension, this study tested the hypothesis that transplantation of exogenous viable mitochondria can reverse pulmonary artery remodeling and restore right ventricular performance in pulmonary hypertension. MethodsPulmonary hypertension was induced by parenteral injection of monocrotaline (60 mg/kg) and creation of a left-to-right shunt aortocaval fistula in rats. Three weeks after creation of fistula, the animals were randomly assigned to receive intravenous delivery of placebo solution or allogeneic mitochondria once weekly for 3 consecutive weeks. Mitochondria (100 μg) were isolated from the freshly harvested soleus muscles of naïve rats. Transthoracic echocardiography was performed at 3 weeks after mitochondrial delivery. ResultsEx vivo heart-lung block images acquired by an IVIS Spectrum (PerkinElmer, Waltham, Mass) imaging system confirmed the enhancement of MitoTracker (Invitrogen, Carlsbad, Calif) fluorescence in the pulmonary arteries. Mitochondria transplantation significantly increased lung tissue adenosine triphosphate concentrations and improved right ventricular performance, as evidenced by a reduction in serum levels of B-type natriuretic peptide and ventricular diameter. Right ventricular mass and wall thickness were restored in the mitochondrial group. In the pulmonary arteries of rats that received mitochondrial treatment, vascular smooth muscle cells expressed higher levels of α-smooth muscle actin and smooth muscle myosin heavy chain II, indicating the maintenance of the nonproliferative, contractile phenotype. The hyper-reactivity of isolated pulmonary arteries to α-adrenergic stimulation was also attenuated after mitochondrial transplantation. ConclusionsTransplantation of viable mitochondria can restore the contractile phenotype and vasoreactivity of the pulmonary artery, thereby reducing the afterload and right ventricular remodeling in rats with established pulmonary hypertension. The improvement in overall right ventricular performance suggests that mitochondrial transplantation can be a revolutionary clinical therapeutic option for the management of pulmonary hypertension.

Osthole inhibits cell proliferation by regulating the TGF-β1/Smad/p38 signaling pathways in pulmonary arterial smooth muscle cells

Pulmonary artery smooth muscle cell (PASMC) proliferation contributes to pulmonary vascular remodeling, which ultimately leads to pulmonary arterial hypertension (PAH). Osthole has been previously shown to inhibit tumor cell growth. Our previous experiments demonstrated that osthole could prevent monocrotaline-induced PAH and pulmonary artery remodeling in rats and that its effects might be associated with inhibiting PASMC proliferation. However, the exact mechanism remains unclear. In this study, we observed the inhibitory effect of osthole on platelet-derived growth factor (PDGF)-BB-induced rat PASMC growth, cell cycle progression and proliferating cell nuclear antigen (PCNA) expression, as measured by CCK-8 assay, flow cytometric analysis and western blotting, respectively. We also detected the expression and activities of the cell cycle regulators cyclin D1/CDK4, cyclin E1/CDK2, p53, p27 and p21 and the TGF-β1/Smad/p38 signaling pathways in rat PASMCs by western blotting. Our results show that osthole effectively suppressed PDGF-BB-stimulated proliferation, PCNA protein expression, and cell cycle progression in rat PASMCs in vitro. We further demonstrated that treatment with osthole significantly induced cell cycle arrest at the G0/G1 phase in PASMCs, which was supported by the finding that osthole significantly decreased cyclin D1/CDK4 and cyclin E1/CDK2 protein levels and increased p53, p27 and p21 protein levels. These effects may partly be attributed to the downregulation of TGF-β1/Smad/p38 signaling pathway activation. Our findings suggest that osthole is a potential therapeutic candidate that warrants further investigation regarding its potential use for the treatment of PAH.

Pulmonary arterial input impedance reflects the mechanical properties of pulmonary arterial remodeling in rats with pulmonary hypertension

AimsAlthough pulmonary arterial remolding in pulmonary hypertension (PH) changes the mechanical properties of the pulmonary artery, most clinical studies have focused on static mechanical properties (resistance), and dynamic mechanical properties (compliance) have not attracted much attention. As arterial compliance plays a significant role in determining afterload of the right ventricle, we evaluated how PH changes the dynamic mechanical properties of the pulmonary artery using high-resolution, wideband input impedance (ZPA). We then examined how changes in ZPA account for arterial remodeling. Clarification of the relationship between arterial remodeling and ZPA could help evaluate arterial remodeling according to hemodynamics. Main methodsPH was induced in Sprague–Dawley rats with an injection of Sugen5416 (20 mg/kg) and 3-week exposure to hypoxia (10% oxygen) (SuHx). ZPA was evaluated from pulmonary artery pressure and flow under irregular pacing. Pulmonary histology was examined at baseline and 1, 3, and 8 weeks (n = 7, each) after Sugen5416 injection. Key findingsSuHx progressively increased pulmonary arterial pressure. ZPA findings indicated that SuHx progressively increased resistance (baseline: 9.3 ± 3.6, SuHx1W: 20.7 ± 7.9, SuHx3W: 48.8 ± 6.9, SuHx8W: 62.9 ± 17.8 mm Hg/mL/s, p < 0.01) and decreased compliance (baseline: 11.9 ± 2.1, SuHx1W: 5.3 ± 1.7, SuHx3W: 2.1 ± 0.7, SuHx8W: 1.9 ± 0.6 × 10−3 mL/mm Hg, p < 0.01). The time constant did not significantly change. The progressive reduction in compliance was closely associated with wall thickening of small pulmonary arteries. SignificanceThe finding that changes in resistance were reciprocally associated with those in compliance indicates that resistant and compliant vessels are anatomically inseparable. The analysis of ZPA might help evaluate arterial remodeling in PH according to hemodynamics.

Dipeptidyl peptidase IV (DPP-4) inhibition alleviates pulmonary arterial remodeling in experimental pulmonary hypertension

Dipeptidyl peptidase IV (DPP-4) is well known for its role in glucose homeostasis, and DPP-4 inhibitor (DPP-4i) exhibits multiple actions in cardiovascular diseases. However, the effect of DPP-4i on pulmonary hypertension (PH) remains unclear. Therefore, this study aims to investigate the effect of DPP-4i on pulmonary arterial remodeling in rats with PH and the potential underlying mechanisms. Our results show that DPP-4 was expressed in epithelial cells, endothelial cells, smooth muscle cells, and inflammatory cells in lung. DPP-4i (Sitagliptin) attenuated right ventricular systolic pressure (RVSP), right ventricle remodeling, hypertrophy of pulmonary arterial medial layer, inflammatory cell infiltration, and endothelial–mesenchymal transition (EndMT) in monocrotaline (MCT)-induced PH rats. Similarly, DPP-4i also alleviated bleomycin- and chronic hypoxia-induced PH in rats. In cultured human pulmonary arterial smooth muscle cells (PASMCs), DPP-4i inhibited platelet derived growth factor (PDGF)-BB-induced proliferation and migration, which was abolished by phosphatase and tensin homolog deleted on chromosome ten (PTEN) knockout. These results demonstrate that DPP-4 inhibition alleviates pulmonary arterial remodeling in experimental PH by inhibiting proliferation and migration of PASMCs.Currently, therapeutic choices for patients with pulmonary hypertension (PH) are limited. This paper reveals that dipeptidyl peptidase IV inhibition alleviates pulmonary arterial remodeling in PH by decreasing the proliferation and migration of pulmonary arterial smooth muscle cells by regulating PTEN/AKT/MAPK signaling. Therefore, soluble DPP-4 might be a diagnostic or prognostic marker for PH; and DPP-4 inhibitors, potential treatments.

STVNa attenuates right ventricle hypertrophy and pulmonary artery remodeling in rats induced by transverse aortic constriction

Right heart failure and pulmonary artery remodeling resulting from increased left heart pressure are prevalent in a clinical setting, and the specific pathological feature exhibits cancer-like cell proliferation in lung. STVNa has been previously demonstrated its anti-proliferation property. In this study, we want to verify the therapeutic effect of STVNa against right ventricle hypertrophy and pulmonary artery remodeling in rats induced by transverse aortic constriction (TAC). The results show that TAC surgery increased mean right ventricle pressure (mRVP) less in the STVNa group than that in the vehicle group (11.81 vs 22.71 mmHg/ml, p < 0.01). STVNa treatment reduced the right ventricle cardiomyocyte area (p < 0.05) and the proliferation of pathological smooth muscle cells proving by PCNA immunohistochemical staining. Gene expression of brain natriuretic peptide (BNP), smooth muscle actin (SMA) and CD31 assessed by real-time polymerase chain reaction were confirmed the above results. Also, STVNa treatment decreased the lung fibrosis content and alleviated the inflammation infiltration. The expression of ET-1 and the phosphorylation of signal-regulated kinase (ERK) were lower in STVNa group compared to vehicle group (p < 0.05). In summary, STVNa could relieve right ventricle hypertrophy and pulmonary artery remodeling formation in rats after 9 weeks of TAC surgery by reducing ET-1 expression and suppressing ERK phosphorylation signal and subsequently inhibiting cell proliferation.

PCPA protects against monocrotaline-induced pulmonary arterial remodeling in rats: potential roles of connective tissue growth factor.

The purpose of this study was to investigate the mechanism of monocrotaline (MCT)-induced pulmonary artery hypertension (PAH) and determine whether 4-chloro-DL-phenylalanine (PCPA) could inhibit pulmonary arterial remodeling associated with connective tissue growth factor (CTGF) expression and downstream signal pathway. MCT was administered to forty Sprague Dawley rats to establish the PAH model. PCPA was administered at doses of 50 and 100 mg/kg once daily for 3 weeks via intraperitoneal injection. On day 22, the pulmonary arterial pressure (PAP), right ventricle hypertrophy index (RVI) and pulmonary artery morphology were assessed and the serotonin receptor-1B (SR-1B), CTGF, p-ERK/ERK were measured by western blot or immunohistochemistry. The concentration of serotonin in plasma was checked by ELISA. Apoptosis and apoptosis-related indexes were detected by TUNEL and western blot. In the MCT-induced PAH models, the PAP, RVI, pulmonary vascular remodeling, SR-1B index, CTGF index, anti-apoptotic factors bcl-xl and bcl-2, serotonin concentration in plasma were all increased and the pro-apoptotic factor caspase-3 was reduced. PCPA significantly ameliorated pulmonary arterial remodeling induced by MCT, and this action was associated with accelerated apoptosis and down-regulation of CTGF, SR-1B and p-ERK/ERK. The present study suggests that PCPA protects against the pathogenesis of PAH by suppressing remodeling and inducing apoptosis, which are likely associated with CTGF and downstream ERK signaling pathway in rats.

Dihydromyricetin prevents monocrotaline-induced pulmonary arterial hypertension in rats

Pulmonary artery hypertension (PAH) is a chronic and deadly disease, for which effective medical treatments are lacking. Here, we investigated whether 2R,3R-dihydromyricetin (DHM) could prevent monocrotaline (MCT)-induced PAH in rats. The MCT-injected rats were treated with normal saline or DHM (100mg/kg body weight/d) for 4 weeks, followed by measurements of right ventricular systolic pressure (RVSP), right ventricular hypertrophy index (RVHI), pulmonary arterial remodeling (PAR), and expression levels of IL-6, TNF-α, and IL-10. In vitro, we assessed the role of DHM on IL-6-induced migration of primary human pulmonary arterial smooth muscle cells (HPASMCs). We found that DHM treatment attenuated changes in RVSP, RVHI, and PAR in MCT-injected PAH rats. The observed increase of IL-6 levels in PAH rats was inhibited by DHM treatment. In vitro, DHM pretreatment reduced IL-6-induced HPASMC migration. Furthermore, MCT- and IL-6-mediated increases in MMP9 and P-STAT3 (tyr705) PY-STAT3 levels were suppressed by DHM treatment in vivo and in vitro. These results suggest that DHM could prevent MCT-induced rat PAH and IL-6-induced HPASMC migration through a mechanism involving inhibiting of the STAT3/MMP9 axis.

Reversal effects of low-dose imatinib compared with sunitinib on monocrotaline-induced pulmonary and right ventricular remodeling in rats

High-dose imatinib reverses cardiopulmonary remodeling but adverse effects limit its clinical use. Efficacy of the multi-kinase inhibitor sunitinib remains questionable. We compared anti-remodeling effects of imatinib with sunitinib on monocrotaline-induced right ventricular (RV) hypertrophy and pulmonary arterial remodeling in rats, focusing on a lower dose. Fourteen days after monocrotaline injection, oral gavage of imatinib (5, 15, or 50mg/kg), sunitinib (0.3, 1, 3, or 10mg/kg), or water for 14days was started. RV hypertrophy and b-type natriuretic peptide mRNA levels were significantly and dose-dependently reduced, much greater in imatinib- than sunitinib-treated groups. Imatinib normalized muscularization of 20–50μm intra-acinar pulmonary arteries more significantly than sunitinib. At transcript levels, sunitinib significantly upregulated pulmonary nestin, and downregulated platelet-derived growth factor receptor beta (PDGFR-β), fibroblast growth factor receptor 1, vascular endothelial growth factor receptor-2 and vascular endothelial growth factor (VEGF)-A, but not Raf-1 proto-oncogene serine/threonine kinase mRNAs. Sunitinib also suppressed VEGF-A, but not phosphorylated extra-cellular-signal-related kinase (ERK)-1/2 protein expression. The sole PDGFR-β antagonism of imatinib resulted in significant Raf-1 mRNA and phosphorylated ERK-1/2 protein downregulation, suggesting that the equivocal reversal effect of sunitinib may be due to its VEGF signaling inhibition in the lung. Imatinib's greater dose-dependent reversal on cardiopulmonary remodeling may make a low dose suitable for PAH treatment.

Prostaglandin E1 Attenuates Pulmonary Artery Remodeling by Activating Phosphorylation of CREB and the PTEN Signaling Pathway

The depletion of cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) and phosphatase and tensin homolog (PTEN) is the critical mediator of pulmonary arterial hypertension (PAH). We hypothesized that the activation of phosphorylated CREB (pCREB) and PTEN could inhibit the AKT signaling pathway to attenuate pulmonary arterial remodeling in rats with monocrotaline-induced PAH. We observed decreased PTEN and pCREB in idiopathic PAH versus control tissue. We reduced PTEN using small interfering RNA in human control pulmonary arterial smooth muscle cells (PASMCs) and observed an increase in pAKT. Consistent with PTEN knockdown in PASMCs, prostaglandin E1 (PGE1) induced pCREB expression to stimulate PTEN protein expression and inhibited pAKT in a time- and dose-dependent manner. The enhanced proliferation and migration of PASMCs following PTEN knockdown were significantly inhibited by PGE1 treatment. The PGE1-induced elevation of PTEN expression in PTEN-depleted PASMCs was decreased by the application of a PKA inhibitor and a CBP-CREB interaction inhibitor. Supplementation with a novel emulsion composition comprising PGE1 in rats with monocrotaline-induced PAH prevented pulmonary arterial remodeling and improved hemodynamics via the induced expression of PTEN. We conclude that PGE1 recruits pCREB/PTEN to decrease the migration and proliferation of PASMCs associated with PAH. This finding elucidates a relevant underlying mechanism of the PGE1/CREB/PTEN signaling pathway to prevent progressive PAH.

Thymoquinone attenuates monocrotaline-induced pulmonary artery hypertension via inhibiting pulmonary arterial remodeling in rats

BackgroundPulmonary artery remodeling induced by excess proliferation, migration and apoptosis resistance of pulmonary arterial smooth muscle cells (PASMCs) is a key component in pulmonary artery hypertension (PAH). Thymoquinone (TQ) triggers cancer cells apoptosis through multiple mechanisms. In addition, TQ inhibits migration of human nonsmall-cell lung cancer cells and human glioblastoma cells. ObjectivesIn the current study, we investigated effects of TQ on MCT-induced PAH in rats and its underlying mechanisms. MethodsAfter 2weeks of monocrotaline injection (MCT, 60mg/kg), Male Sprague–Dawley rats received TQ (8mg/kg, 12mg/kg, 16mg/kg) or olive oil per day for 2weeks. Hemodynamic changes, right ventricular hypertrophy, and lung morphological features were examined 4weeks later. In addition, TUNEL, PCNA, α-SMA, Bax and Bcl-2 were detected by immunohistochemistry staining. Bax, Bcl-2, cleaved caspase-3, cleaved poly (ADP-ribose) polymerase (PARP) MMP2, MMP9 and activation of p38MAPK and NF-κB were assessed by Western blot. ResultsMCT-induced an increase in pulmonary blood pressure and right ventricular hypertrophy, which were attenuated by TQ treatment. TQ also blocked MCT-induced pulmonary arterial remodeling, proliferation of PASMCs, elevation of MMP2 and downregulation of ratio of Bax/Bcl-2, cleaved caspase-3 and cleaved PARP. Furthermore, TQ inhibited MCT-induced activation of p38MAPK and NF-κB. ConclusionsTQ ameliorates MCT-induced pulmonary artery hypertension by inhibiting pulmonary arterial remodeling partially via p38MAPK/NF-κB signaling pathway in rats.

The role of PDGF-B/TGF-β1/neprilysin network in regulating endothelial-to-mesenchymal transition in pulmonary artery remodeling

Endothelial-to-mesenchymal transition (EndoMT) has been recognized as a major reason for the pulmonary artery remodeling (PAR) in pulmonary artery hypertension (PAH). However, the molecular mechanisms and regulatory pathways involved in the EndoMT remain undefined. In the present study, we have confirmed that EndoMT was occurred in pulmonary arteries of rats induced by hypoxia and monocrotaline and in hypoxic pulmonary artery endothelial cells (PAECs). Moreover, hypoxia increased the expression of platelet-derived growth factor (PDGF) and transforming growth factor-β1 (TGF-β1) and decreased the expression of neprilysin (NEP), which contributed to the hypoxia-induced EndoMT of PAECs. Furthermore, a reciprocal regulation of PDGF-B and TGF-β1 induced by decreasing NEP promoted the EndoMT of PAECs under hypoxia, which was a novel molecular mechanism to reveal the EndoMT participating in PAR. More importantly, imatinib, a PDGF receptor antagonist, relieved PAR and EndoMT in PAH rats. Thus, our results identify a novel mechanism to reveal the formation of EndoMT in PAH, and imply that imatinib may serve as a new therapeutic approach for treatment of the third cardiovascular disease.

Activation of peroxisome proliferator-activated receptor γ ameliorates monocrotaline-induced pulmonary arterial hypertension in rats.

Activation of peroxisome proliferator-activated receptor γ (PPARγ) suppresses the proliferation of pulmonary artery smooth muscle cells (PASMCs) and vascular remodeling in rats and humans, and therefore improves the development of pulmonary arterial hypertension (PAH). However, molecular mechanisms underlying these effects have not been completely understood. In the present study, the effects of PPARγ activation in monocrotaline (MCT)-induced pulmonary artery remodeling in rats were investigated. Eighteen Sprague-Dawley (SD) rats were randomly assigned into three groups (n=6): Control (Con), PAH and PAH treated with rosiglitazone (MCT + Rosi). The right ventricular systolic pressure (RVSP), the ratio of the right to left ventricle plus septum weight [RV/(LV + S)], the percentage of medial wall thickness (%MT) and wall area (%WA) were used to evaluate the development of PAH. Tissue morphology was measured using hematoxylin and eosin staining. The protein levels of the phosphatase and tensin homologue deleted on chromosome ten (PTEN), Akt (ser473) phosphorylation (p-Akt) and total Akt in intrapulmonary arteries were determined by western blot analysis. MCT treatment significantly increased the RVSP, which was reduced by rosiglitazone treatment. The ratio of RV/(LV + S), %MT and %WA induced by MCT were similarly inhibited, which was associated with the increase of PTEN expression and the inhibition of Akt phosphorylation levels by rosiglitazone. In conclusion, activation of PPARγ ameliorates the proliferation of PASMCs and vascular remodeling by regulating the PTEN/PI3K/Akt pathway, suggesting that the activation of PPARγ has potential benefits for PAH.

The effect of PS-341 on pulmonary vascular remodeling in high blood flow-induced pulmonary hypertension

The aim of the present study was to investigate the effects of PS-341 on vascular remodeling in an experimental rat model of high blood flow-induced pulmonary arterial hypertension (PAH), as well as to elucidate its mechanisms of action. We established the PAH model by a surgical method that implanted a left-to-right shunt. Three days post-surgery, the animals were randomly assigned to 3 groups (n=15 in each group): sham-operated (control), shunt (model) and PS-341 (treated) groups. Eight weeks post-surgery, hemodynamic parameters were significantly improved in the PS-341 group compared with the shunt group (P<0.05). Immunohistochemical analysis indicated that the expression levels of ubiquitin and nuclear factor-κB (NF-κB) p65 were significantly higher in the shunt group compared with the sham-operated group (P<0.05). Semi-quantitative western blot analysis further confirmed that the levels of ubiquitin and NF-κB p65 were decreased, while those of IκB-α (an inhibitor of NF-κB) were significantly increased in the PS-341 group compared with the shunt group (P<0.05). In conclusion, PS-341 attenuates high blood flow-induced pulmonary artery remodeling in rats via inhibition of the NF-κB pathway.

Serotonin inhibits apoptosis of pulmonary artery smooth muscle cells through 5-HT2A receptors involved in the pulmonary artery remodeling of pulmonary artery hypertension

ABSTRACTDecreased pulmonary artery smooth muscle cell (PASMC) apoptosis play a key role in pulmonary artery remodeling during pulmonary artery hypertension (PAH), but the mechanisms involved are unclear. Serotonin (5-HT) inhibits apoptosis in many pathologic processes by activating the 5-HT2A receptor. Therefore, we hypothesized that 5-HT may be the promoter of decreased apoptosis in PAH through the 5-HT2A receptor. We found that inhibition of the 5-HT2A receptor prevented the increase in pulmonary artery pressure and pulmonary artery remodeling in rats stimulated by monocrotaline. This effect was accompanied by increased apoptosis in the pulmonary artery. Cultured PASMCs stimulated with 5-HT showed a decrease in apoptosis with increased phosphorylation of extracellular signal regulated kinase 1/2 (ERK1/2), pyruvate dehydrogenase kinase (PDK), and mitochondrial transmembrane potential. These effects were markedly prevented by a 5-HT2A receptor inhibitor, an ERK1/2 activation inhibitor peptide I, or a PDK inhibitor. In conclusion, 5-HT inhibited PASMC apoptosis by activating the 5-HT2A receptor through the pERK1/2 and PDK pathways.5-HT decreasing apoptosis through 5-HT2A receptor is involved, at least in part, in pulmonary artery remolding.

Effects of exercise on monocrotaline-induced changes in right heart function and pulmonary artery remodeling in rats

Pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT) is an experimental protocol of right heart failure. We analyzed the role of exercise training on the right ventricle structure and function, pulmonary artery remodeling, and GSK-3β expression. Rats were divided among the following groups: sedentary control (SC), sedentary monocrotaline (SM), trained control (TC), and trained monocrotaline (TM). Rats underwent exercise training for a period of 5 weeks, with 3 weeks post-MCT injection. Rats in the SM and TM groups presented with an increase in right ventricle hypertrophy indexes and lung congestion. The right ventricular end diastolic pressure (RVEDP), right ventricular systolic pressure (RVSP), and its minimum and maximal pressure derivates were increased in the SM and TM groups. The right ventricle interstitial volume pulmonary artery thickness and p-GSK-3β/GSK-3β were increased in the MCT groups as compared with the control groups. The TM group had a reduction in interstitial volume, p-GSK-3β/GSK-3β ratio, pulmonary artery thickness, RVEDP, and an increase in intramyocardial vessels volume as compared with the SM group. The overall results have shown that the exercise protocol used promoted positive changes in right ventricle and pulmonary artery remodeling. These observations also suggest that structural remodeling may be influenced by signaling proteins, such as GSK-3β.

Fluoxetine inhibits monocrotaline-induced pulmonary arterial remodeling involved in inhibition of RhoA–Rho kinase and Akt signalling pathways in rats

Activation of the small GTPase Ras homolog gene family member A (RhoA) and Rho-associated kinase (ROCK) are important in the pathogenesis of pulmonary arterial hypertension (PAH). Selective serotonin reuptake inhibitors inhibit activation of RhoA and ROCK in vitro, and ameliorate PAH and pulmonary arterial remodeling in vivo. However, little is known about whether the RhoA-ROCK signalling pathway is involved in the treatment of PAH with fluoxetine in vivo. The aim of the present study was to investigate the involvement of the RhoA-ROCK signalling pathway in the protective effect of the selective serotonin reuptake inhibitor fluoxetine against monocrotaline (MCT)-induced pulmonary arterial remodeling. MCT was applied to establish PAH in male Wistar rats. Fluoxetine was administered by gastric gavage once a day for 21 d. The results showed that MCT induced pulmonary arterial remodeling, raised the serotonylation and membrane translocation of RhoA in the lungs, and increased serotonin transporter (5-HTT), RhoA, and ROCK2 expression, and extracellular signal-regulated kinase (ERK) and Akt phosphorylation in the pulmonary arteries and the lungs. Fluoxetine markedly inhibited these MCT-induced changes. The findings suggest that fluoxetine inhibits MCT-induced pulmonary arterial remodeling in rats by inhibition of the RhoA-ROCK and Akt signalling pathways.

Effects of adipose tissue-derived mesenchymal stem cells on monocrotaline-induced pulmonary arterial remodeling in rats

Objective: To investigate the effects of adipose-derived mesenchymal stem cells (ADMSC) on monocrotaline-induced pulmonary arterial hypertension and remodeling in rats. Methods: ADMSC were isolated from adipose tissue of rat's groin by type I collagenase digestion, and infected by adenoviral vector transfected with green fluorescent protein (GFP). Ninety Sprague–Dawley rats were randomly assigned to three groups: ADMSC treated, untreated and control groups. Pulmonary arterial hypertension (PAH) was induced by a dose of 40mg/kg monocrotaline intraperitoneally and Ctr rats were given 1mL normal saline intraperitoneally.

Effects of Atorvastatin and Losartan on Monocrotaline-Induced Pulmonary Artery Remodeling in Rats

Structural remodeling of pulmonary artery plays an important role in maintaining sustained pulmonary arterial hypertension (PAH). The anti-remodeling effects of statins have been reported in systemic hypertension. In this study, we studied the effects of atovastatin (Ato) or losartan (Los) in monocrotaline (MCL)-induced pulmonary artery remodeling using a rat model. Forty Sprague-Dawley (SD) rats were randomly assigned into four groups (n == 10): normal control (Ctr), PAH, PAH treated with Los, and PAH treated with Ato. We found that in the Los- or Ato-treated group, the mean pulmonary arterial pressure, right heart hypertrophy index, ratio of wall//lumen thickness (WT%%), as well as the wall//lumen area (WA%%) were significantly reduced compared to the PAH group. Also in pulmonary arteries dissected from rats in the Ato- or Los-treated group, in both mRNA and protein levels, the expression of α1C subunit of voltage-gated calcium channel (Cavα1c) was downregulated, while sarcoplasmic//endoplasmic reticulum calcium-ATPase (SERCA-2a) and inositol 1,4,5 triphosphate receptor 1 (IP3R-1) upregulated. However, the mRNA level of RyR-3 subunit of calcium regulating channel was increased, whereas its protein level was reduced in the treated groups. Our results suggest that atorvastatin or losartan may regress the remodeling of the pulmonary artery in pulmonary hypertensive rats, with differential expression of calcium regulating channels.