Effects of chronic hypoxia on intracellular calcium concentration in pulmonary arterial smooth muscle cells

AIM:To study the effect of chronic hypoxia (CH) on the intracellular calcium (［²⁺］_i) in pulmonary artery smooth muscle cells (PASMCs) and the role of L-type calcium channel and calcium store. METHODS:The rat chronic hypoxia model was set up and intervene the PASMCs with normal PSS, calcium-free PSS, nifedipine, and heparine respectively. The resting ［Ca²⁺］_i was determined with the Fura-2/AM calcium imaging technique. RESULTS:(1) The ［Ca²⁺］_i in CH group in normal PSS was higher than that in control group in normal PSS (P<0.05). The ［Ca²⁺］_i in CH group in normal PSS was higher than that in calcium-free PSS (P<0.05). (2) No obvious change of ［Ca²⁺］_i before and after application of nifedipine in PASMCs of CH groups was observed. (3) No difference of ［Ca²⁺］_i before and after application of heparine in PASMCs of CH groups was detected. CONCLUSION:Chronic hypoxia increased the ［Ca²⁺］_i in PASMCs. Chronic hypoxia induced increase in ［Ca²⁺］_i may relate to the influx of extracellular calcium, but not due to the L-type calcium channel or the IP3R modulation only.     

Role of intracellular free Ca2+ concentration in the regulation of calcium-activated chloride channels in rat pulmonary artery smooth muscle cells

AIM: To investigate the role of intracellular free Ca²⁺ concentration (［Ca²⁺］_i) in the regulation of calcium-activated chloride (Cl_Ca) channels in pulmonary artery smooth muscle cells (PASMCs) of rats under normoxic, acute and chronic hypoxic conditions. METHODS: Acute hypoxia-induced contraction was observed in rat pulmonary artery by using routine blood vascular perfusion in vitro. The fluorescence Ca²⁺ indicator Fura-2/AM was used to observe ［Ca²⁺］_i of rat PASMCs in normal and chronic hypoxic condition. The influences of Cl_Ca channels on PASMCs proliferation were assessed by MTT assay. RESULTS: (1) The Cl_Ca channel blockers niflumic acid (NFA) and indaryloxyacetic acid (IAA-94) produced inhibitory effects on acute hypoxia-evoked contractions in pulmonary artery. (2) Under chronic hypoxic condition, ［Ca²⁺］_i was increased. In normoxic condition, ［Ca²⁺］_i was (123.63±18.98) nmol/L, and in hypoxic condition, ［Ca²⁺］_i was (281.75±16.48)nmol/L (P<0.01). (3) In normoxic condition, ［Ca²⁺］_i had no significant change and no effect on Cl_Ca channels was observed (P>0.05). (4) Chronic hypoxic increased ［Ca²⁺］_i which opened Cl_Ca channels. The NFA and IAA-94 blocked them and decreased ［Ca²⁺］_i from (281.75±16.48)nmol/L to (117.66±15.36)nmol/L (P<0.01). (5) MTT assay showed that in chronic hypoxic condition NFA and IAA-94 decreased the value of absorbing light degree (A value) from 0.459±0.058 to 0.224±0.025 (P<0.01). CONCLUSION: Hypoxia increased ［Ca²⁺］_i which opened Cl_Ca channels and had a positive-feedback to ［Ca²⁺］_i. This may play an important role in hypoxic pulmonary hypertension. In chronic hypoxic condition, Cl_Ca channel may play a role in the regulation of PASMCs proliferation.     

Neuropeptide Y induced redistribution of intracellular free calcium in rat cardiomyocytes

AIM: To investigate the effect of neuropeptide Y (NPY) on intracellular free calcium(［Ca²⁺］_i) and Ca²⁺ sarcoplasmic reticulum of cardiomyocytes in rats.METHODS: Cardiomyocytes of neonatal Sprague-Dawley rats were incubated with NPY at concentration of 100 nmol/L for 24 h. Fluorescent indicator Fluo-4 AM was used to detect ［Ca²⁺］_i and Fluo-5N AM was used to detect Ca²⁺ in sarcoplasmic reticulum (SR). Calcium image was recorded by laser scanning confocal microscope. The SR Ca²⁺ load was estimated by caffeine-induced Ca2+ transient (CCT). RESULTS: 24 h after incubation with NPY, compared with control group, the concentration of ［Ca²⁺］_i was significantly elevated (P<0.05), and the concentration of free Ca2+ in SR (［Ca²⁺］_SR) was significantly decreased (P<0.05), and the peak of CCT was attenuated.CONCLUSION: Stimulation with NPY for 24 h causes redistribution of free calcium in rat cardiomyocytes, namely the elevation in ［Ca²⁺］_i and decline in ［Ca²⁺］_SR.     

Changes of ［Ca2+］i and the activity of ACE in alveolar macrophages of rabbits with high-fat diet

AIM: To investigate the effects of high-fat diet on the level of intracellular free calcium (［Ca²⁺］_i) and the activity of angiotensinⅠconverting enzyme (ACE) in alveolar macrophages (AMs) of rabbits.The association between asthma and high-fat diet was also observed.METHODS: Twelve male New Zealand rabbits were medially divided into normal diet group and 1.2% high-cholesterol diet group randomly.8 weeks later,bronchial alveolar lavage was performed in vitro.［Ca²⁺］_i was determined by Fluo-2/am.The activity of ACE was detected with ultraviolet method.RESULTS: The levels of ［Ca²⁺］_i in AMs greatly increased (P＜0.01).The activity of ACE both in BALF and in culture supernatants of AMs was all greatly increased compared with normal diet group (P＜0.01).In hypercholesterolemic group the number of macrophages in BALF showed a positive correlation with the content of cholesterol in serum,such as the level of ［Ca²⁺］_i in AMs and the activity of ACE in the culture supernatants of AMs (all P＜0.05).CONCLUSION: The results suggest that AMs of rabbits may be activated by hyperlipoidemia and become ease to be stimulated.     

Calcineurin signal transduction pathway involves in cardiomyocyte hypertrophy induced by prostaglandin F2α

AIM: To study the role of prostaglandin F₂α (PGF₂α) in cardiac hypertrophy and its relation with calcineurin (CaN) signal transduction pathway in vitro. METHODS: The cultured neonatal rat cardiomyocyte was used to observe the hypertrophic effect of PGF2α, and the hypertrophic response was assayed by measuring the cell diameter, protein content and atrial natriuretic factor (ANF) mRNA expression. For mechanism studies, the intracellular free calcium concentration (［Ca²⁺］_i) in cultured cardiomyocytes was measured by using Fura-2/AM as a fluorescent indicator. ANF and CaN mRNA expressions, and the expressions of CaN and its downstream effectors, NFAT₃ and GATA₄ proteins were assayed by RT-PCR and Western blotting, respectively.RESULTS: In cultured cardiomyocytes, PGF₂α induced profound hypertrophic morphology change, the significant increase in cell diameter and protein content in a concentration-dependent manner compared with those in vehicle control (P<0.01). The same result was found in measuring the ［Ca²⁺］_i in cardiomyocytes (P<0.01). PGF₂α at concentration of 10-7 mol/L significantly promoted ANF and CaN mRNA expressions and the protein expressions of CaN/NFAT₃/GATA₄ compared with those in the vehicle control (P<0.05). Cyclosporin A, a CaN inhibitor, markedly inhibited the myocyte hypertrophy (P<0.01), reduced the increased ［Ca²⁺］_i(P<0.01) and decreased the expressions of CaN mRNA and CaN/NFAT₃/GATA₄ proteins (P<0.05) compared with those of only PGF₂α　10^-7 mol/L treatment. CONCLUSION: Cardiomyocyte hypertrophy induced by PGF2α may be, at least in part, mediated by CaN signal transduction pathway activated by increasing ［Ca²⁺］_i.     

Angiopoietin-1 increases intracellular free Mg2+ by tyrosine kinase/PI3K in HUVECs

AIM:The mechanism of angiopoietin-1 (Ang-1) in mediating increase in intracellular free magnesium (［Mg²⁺］_i) in human umbilical vein endothelial cells (HUVECs) was investigated in this study. METHODS:The change of ［Mg²⁺］_i in HUVECs was quantitatively detected in intracellular cation measurement system via loaded with the fluorescent magnesium indicator mag-fura-2. RESULTS:Ang-1 increased ［Mg²⁺］_i, and there was not any significant difference among the groups of 0 mmol/L and 1 mmol/L of extracellular Mg2+. Similar results were obtained in groups done with Ca2+. Pretreatment with tyrosine kinase inhibitors (tyrphostin A23 and genistein), phosphatidylinositol 3-kinase (PI3K) inhibitors (wortmannin and LY294002) blocked the increase in ［Mg²⁺］_i induced by Ang-1. However, mitogen-activated protein kinase inhibitors (SB202190 and PD98059) had no effect on the Ang-1-induced ［Mg²⁺］_iincrease. CONCLUSION:These results suggest that the increase in ［Mg²⁺］_i by Ang-1 come from intracellular Mg2+ pools mediated by tyrosine kinase/PI3K -dependent signaling pathways.     

Effects of endothelin-1 on the induction of the transdifferentiation of human airway sub-epithelial fibroblasts

AIM: To explore the role of endothelin-1 (ET-1) in initiating transdifferentiation of sub-epithelial fibroblasts (SEFs) into myofibroblasts and its ionic and signal transduction mechanism.METHODS: Human SEFs or SEFs plated in collagen gels were co-cultured with human bronchial epithelial cells (16HBE) treated with lipopolysaccharide (LPS) plus mechanical scratch. ET receptor A inhibitor (BQ123) or the inhibitors specific for p38 MAPK, ERK1/2 were added, repectively. The expression of α-smooth muscle actin (α-SMA) in the SEFs and contractility of the collagen gels containing with SEFs as well as the effects of p38 MAPK or ERK1/2 on α-SMA expression were evaluated. Using Ca2+ sensitive Fluo-3/AM, dynamic changes of intracellular calcium concentration (［Ca²⁺］_i) were observed in the SEFs by laser confocal microscopy.RESULTS: Injured 16HBE induced the transdifferentiation of myofibroblasts, which expressd α-SMA and increased contractility. BQ123 blocked the induction to a certain extent. Injured 16HBE activated p38 MAPK and ERK1/2 pathways in SEFs, both inhibitors of p38 MAPK and ERK1/2 attenuated the induction of α-SMA by injured 16HBE. The addition of exogenous ET-1 enhanced α-SMA expression and activated p38 MAPK, ERK1/2 pathways in the SEFs. Additionally, ET-1 significantly facilitated Ca²⁺ inflow into the fibroblasts.CONCLUSION: Injured 16HBE induces the transdifferentiation of SEFs into myofibroblasts, which is involved in the activation of p38 MAPK and ERK1/2 pathways. The ET-induced influx of Ca²⁺ may be an early signal for initiating the myofibroblasts transdifferentiation.     

Influence of MTHFR genetic polymorphism on the indexes of vascular endothelial functions

AIM: To investigate the influence of methylenetetrahydrofolate reductase (MTHFR) 677 C→T mutation on angiotensin Ⅱ (Ang II), prostacyclin (PGI₂) and nitric oxide (NO). METHODS: By cluster sampling, 1146 adult Han people were selected from the residential communities. MTHFR 677 genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism for each sample. Plasma levels of homocysteine were determined by fluorescence ration biochemical assay. Serum NO levels were determined by cadmium reduction method. Plasma AngⅡ and PGI₂ concentrations were determined by radioimmunoassay. SPSS 13.0 was used for data analysis. RESULTS: Total samples were divided into three groups according to the genotypes. No significant difference in PGI₂ and AngⅡamong the three groups was observed. The difference of serum NO level between the C/C and T/C genotypes was not significant (P>0.05). The serum concentration of NO of T/T genotype was significantly lower than that of T/C and C/C genotypes (P<0.01). CONCLUSION: The influence of MTHFR 677 C→T mutation on Ang II and PGI₂ is not significant in the people from the residential communities. The decrease in serum NO level might be one of the underlying mechanisms of MTHFR 677 C→T mutation causing myocardial infarction and ischemic stroke.     

Effects of luteolin on endothelial cell injury induced by H2O2

AIM: To study the effect of luteolin on endothelial cell injuries induced by H₂O₂. METHODS: Endothelial cells were cultured in vitro and divided into seven groups: control; solvent; H₂O₂; quercetin+H₂O₂; luteolin-L+H₂O₂; luteolin-M+H₂O₂; luteolin-H+H₂O₂ group, respectively. Endothelial cells were incubated with 750 μmol/L H₂O₂ for 18 h or 14 h in the absence or presence of various concentrations of luteolin and quercetin. The expression of caspase-3, the pro-apoptotic factors, was detected by immunohistochemical technique, and the apoptotic index was detected by flow cytometry. Meanwhile, the amount of malondialdehyde (MDA), nitric oxide (NO), lacate dehydrogenase (LDH) in serum, and cell viability were measured. RESULTS: Incubation of endothelial cells with H₂O₂ for 18 h elicited the increase in the extent of immunostaining for caspase-3, the rate of apoptosis, the release of LDH, and the number of dead cells accompanied by the decrease in the content of NO in the medium, which were inhibited by pretreatment of luteolin at concentrations of 0.5-50 μmol/L in a concentration-dependent manner (P<0.01). CONCLUSION: Luteolin possesses a protective effect against endothelial cell injuries induced by H₂O₂, which may be related with anti-oxidation, increasing the concentration of NO and inhibiting the activation of caspase-3.     

Effect of curcuma aromatica oil on learning,memory and hippocampal p-CaMKII expression in rats exposed to chronic hypoxia

AIM: To investigate the effects of different concentrations of curcuma aromatica oil on learning and memory in rats exposed to chronic hypoxia. METHODS: The rats were divided randomly into the control, chronic hypoxia and chronic hypoxia with low (LC), middle (MC) and high (HC) concentrations of curcuma aromatica oil groups. After 29 d, all animals were examined to obtain the scores of leaning and memory. The SOD activity and MDA content were determined in the serum and hippocampus, the ［Ca2+］_i in hippocampus was also detected. The staining and expression of p-calcium/calmodulin-dependent protein kinase II (p-CaMKII) in the hippocampus was observed and measured. RESULTS: ① In the chronic hypoxia group, the latency to find the hidden platform remarkably prolonged and the MDA content was obviously higher, but the SOD activity was significantly lower. Meanwhile, hippocampal ［Ca2+］_i was markedly increased. The immunostaining of p-CaMKII was much weaker in hippocampus as well as its expressions (P<0.01). ② The latency to find the hidden platform was remarkably shorter in groups with MC and HC (P<0.05). The MDA content was obviously lower among groups treated with curcuma aromatica, but SOD activity was significantly higher in groups with MC and HC. Meanwhile, hippocampal ［Ca2+］_i was markedly decreased in all groups treated with curcuma aromatica oil (P<0.01). The hippocampal immunostaining of p-CaMKII was much stronger in the MC and HC as well as its expression (P<0.05，P<0.01). Under the electron microscope, synaptic boundaries were not distinct, the edema of dendrite spine and axon was seen, synaptic vesicles and postsynaptic densities (PSD) were disappeared in the chronic hypoxia group. With rising of the concentration of curcuma aromatica oil, the edema of synapse and mitochondria was mitigated and the PSD was increased gradually. CONCLUSION: Curcuma aromatica oil might enhance learning and memory capacities of rats exposed to chronic hypoxia by cleaning up and antagonizing the production of the free radical and increasing the p-CaMKII expression in PSD. The effects are dose-dependent.     

Electrophysiological characteristics of the membrane current of cardiomyocytes-like cells derived from rat bone marrow mesenchymal stem cells

AIM: To study the electrophysiological characteristics of the membrane currents of cardiomyocytes-like cells derived from rat bone marrow mesenchymal stem cells (MSCs).METHODS: MSCs were induced,cultured and identified according to the reference.At the fourth week after treatment with 5-azacytidine(5-aza),cardiomyocytes-like cells were detected for the membrane current with the whole-cell patch-clamp technique and compared with the undifferentiated MSCs.RESULTS: The undifferentiated MSCs only expressed potassium currents.MSCs were stained positive for troponin T after treatment with 5-aza,and two kinds of inward currents and three kinds of outward currents were expressed.They respectively were the fast inward sodium current (I_Na),the L-type calcium current (I_Ca),the transient outward potassium current (I_to),the ultra-rapid delayed rectifier potassium current (I_kur) and the slow delayed rectifier potassium current (I_ks).Compared with the undifferentiated MSCs,the potassium currents of cardiomyocytes-like cells derived from MSCs were mainly made up of I_kur and I_ks.CONCLUSION: After treatment with 5-azacytidine,MSCs are differentiated into cardiomyocytes-like cells,which express the current of I_Na,I_Ca,I_to,I_kur and I_ks.     

Serum CTRP1 and CTRP7 levels are associated with coronary atherosclerotic heart disease and diabetes mellitus

AIM To investigate the relationship between the serum levels of C1q/TNF-related protein (CTRP) 1 and CTRP7 and coronary atherosclerotic heart disease (CAD) in the patients with or without type 2 diabetes mellitus (T2DM). METHODS Totally 138 cases of participants were selected, and divided into control group (without T2DM or CAD; n=40), T2DM group (with T2DM, but without CAD; n=30), CAD group (with CAD, but without T2DM; n=40), and CAD+T2DM group (with both T2DM and CAD; n=28). The serum levels of CTRP1 and CTRP7 in these participants were measured by ELISA. RESULTS (1) Compared with control group, serum CTRP1 level in CAD group and CAD+T2DM group was significantly increased (P<0.05 or P<0.01), and serum CTRP7 level in CAD, T2DM and CAD+T2DM groups was significantly decreased (P<0.05 or P<0.01). (2) Increased serum CTRP1 level was a risk factor for CAD [odds ratio (OR)=1.136; 95% confidence interval (CI): 1.010~1.278; P=0.034). Sex, hypertension and serum triglyceride level were also correlated with CAD. Decreased serum CTRP7 level was a risk factor for T2DM (OR=0.984; 95% CI: 0.969~0.999; P=0.038). Sex, hypertension and serum high-density lipoprotein cholesterol level were also correlated with T2DM. Increased serum CTRP1 level was a risk factor for CAD+T2DM (OR=1.009; 95% CI: 1.005~1.203; P=0.040). Hypertension was also a risk factor for CAD+T2DM. (3) In CAD group, serum CTRP1 level had certain diagnostic value, and the area under the receiver operating characteristic (ROC) curve (AUC) was 0.670 (95% CI: 0.580~0.760; P=0.001), but serum CTRP7 level had no diagnostic value for CAD. In T2DM group, both serum CTRP1 and CTRP7 levels had diagnostic value, and the AUC values of their ROC curves were 0.607 (95% CI: 0.505~0.710; P=0.032) and 0.665 (95% CI: 0.574~0.756; P=0.001), respectively. In CAD+T2DM group, both serum CTRP1 and CTRP7 levels had diagnostic value, and the AUC values of their ROC curves were 0.666 (95% CI: 0.552~0.781; P=0.007) and 0.632 (95% CI 0.517~0.747; P=0.032), respectively. CONCLUSION Increased serum CTRP1 level and decreased serum CTRP7 level are associated with increased risk of T2DM and CAD. Increased serum CTRP1 level is a risk factor for CAD and CAD+T2DM, while decreased serum CTRP7 level is a risk factor for T2DM. Serum CTRP1 level has certain specificity and sensitivity for the diagnosis of CAD, T2DM and CAD+T2DM, while serum level of CTRP7 has certain specificity and sensitivity for the diagnosis of T2DM and CAD+T2DM.     

Effect of salvianolic acid B on expression of TGF-β1 receptors and Smad2 in activated mesangial cells

AIM: To study the mechanisms of salvianolic acid B (Sal B)antagonizing mesangial cell activation and kidney fibrosis through investigating the effect of Sal B on expression of transforming growth factor-β₁ (TGF-β₁) receptors and Smad2 in TGF-β₁-stimulated renal mesangial cell activation. METHODS: Mesangial cells was isolated and purified from rat kidney. TGF-β₁ was used to establish rat primary mesangial cell activation model and Smad2,Smad7 protein expression was detected. Sal B (10^-6 mol/L and 10^-5 mol/L) was employed to treat the cells; α-smooth muscle actin(α-SMA) expression was analyzed by immunofluorescence staining and Western blotting. Mesangial cells were treated with Sal B alone or additional with TGF-β₁,and TGF-β₁ receptor Ⅰ (TβRⅠ),TGF-β₁ receptorⅡ (TβRⅡ),Smad2 phosphorylation and Smad2 protein expression was determined by Western blotting. RESULTS: Cell ular model was established by incubating with 5 μg/L TGF-β₁ for 24 h,and in early stage Smad2 was significantly phosphorylated. Sal B (10^-6 mol/L and 10^-5 mol/L) could inhibit α-SMA expression,which was the biomarker of activated mesangial cells. In addition,in Sal B group,the protein expression of TβRⅠand TβRⅡ was significantly down-regulated while Smad2 phosphorylation in mesangial cells was inhibited. CONCLUSION: Sal B inhibits the TGF-β₁-Smad pathway,the protein expression of TβRⅠ,TβRⅡ and Smad2 phosphorylation in mesangial cells,which is probably one of the mechanisms of Sal B alleviating kidney fibrosis.     

Roles of dendritic cells treated with 17β-estradiol in immune tolerance induction in skin allograft

AIM: To study the roles of bone marrow-derived dendritic cells from donor mouse treated with 17β-estradiol (E₂) in immune tolerance induction in skin allograft. METHODS: Bone marrow-derived dendritic cells from C57 mouse as donor were cultured respectively treated with E₂ (E₂ group). BALB/c mouse as recipient received respectively one injection of dendritic cells of E₂ group, mature dendritic cell group and immature dendritic cell group intravenously. Skin transplantation was performed in the absence of immunosupression after 7 d. Mice that received PBS were served as control. The time of skin survival was observed after transplantation. Flow cytometry was used to analyze the percentage of CD4+CD25+ T cells in peripheral blood respectively before and after transplantation. RESULTS: Compared with immature dendritic cells and control group, the time of skin survival in E₂ group was significantly longer (P<0.01), especially, the time of skin survival still prolonged 10.6 d after skin rejection in immature dendritic group. The percentage of CD4+CD25+ regulatory T cells in E₂ group was significantly higher than that in immature dendritic cell group and control group (P<0.01). CONCLUSION: In skin allograft model, dendritic cells treated with E₂ prolong the allograft survival time.     

Mechanisms of PGF2α on the glucose-induced insulin secretion in NIT-1β cells

AIM:To investigate the cellular mechanisms by which PGF₂α promotes glucose-stimulated insulin secretion in NIT-1 beta cells. METHODS:Using the radioimmunoassay (RIA), the amount of the PGF₂α augmentation of glucose stimulated insulin secession was determined in different conditions, and the confocal laser scanning methods by Fluo-3AM as a fluorescent probe were used to analyze the changes of intracellular calcium in NIT-1β cells. RESULTS:At the lower glucose (0, 5.5 mmol/L), PGF₂α (5 μmol/L) failed to potentiate insulin secretion (P>0.05). However, in the presence of 16.5 mmol/L glucose, PGF₂α increased significantly in insulin secretion (P<0.05). Neither the AC inhibitor ddA nor the GC inhibitor Ly-83583 altered PGF₂α-potentiated insulin secretion in the presence of 16.5 mmol/L (P<0.05 or P<0.01). Otherwise, the PLC inhibitor U-73122 and the PKC blocker calphostin C both counteracted the insulinotropic of PGF₂α (P<0.01 or P<0.05). Moreover, exposure of the NIT-1β cells to 5 μmol/L PGF₂α induced a rapid increase of intracellular calcium (P<0.01). The inhibitor, ddA or Ly-83583 had no impact on PGF₂α-induced elevation of the intracellular calcium (P<0.01). Pretreatment of the cells with U-73122 completely prevented the calcium response induced by PGF₂α (P<0.01). CONCLUSION:Efects of PGF₂α was independent of cAMP or cGMP, potentiated glucose (16.5 mmol/L)-induced insulin secretion in NIT-1β cells through stimulation of phospholipase C, which subsequently mediated the elevation of intracellular calcium and activation of protein kinase C.     

Effects of oxygen free radicals and captopril on endogenous NOS inhibitor in human vascular endothelial cells

AIM: To observe the effects of oxygen free radical (OFR) and captopril on the level of asymmetric NG, NG-dimethyl-L-arginine (ADMA) in human vascular endothelial cells (HUVECs).METHODS: HUVECs of 3-6 th passage, cultured with modified Jaffes’ method, were used in the experiment and divided into three groups: (1)Cells cultured with equivalence of DMEM medium as control; (2)OFR intervention groups, OFR at concentrations of 0.01 mmol/L, or 0.1 mmol/L, respectively, were added to the cell culture; (3)Drug intervention groups: the cell culture was treated with 0.1 mmol/L of OFR combined with 50 mg/L or 100 mg/L of captopril, respectively. Concentrations of ADMA, L-arginine, nitric oxide(NO), endothelin(ET) and the activity of angiotensin-converting enzyme(ACE) in conditioned medium were measured after 24 h exposure. RESULTS: Concentrations of ADMA, ET and the activity of ACE were increased, while the amount of NO decreased in OFR intervention groups compared with control group. After treatment with captopril, ADMA, ET concentrations and the activity of ACE were decreased, while the amount of NO increased, but the level of L-arginine had no obvious change. CONCLUSIONS: OFR induces endothelial dysfunction through increasing ADMA concentration, while captopril relieves endothelial dysfunction induced by ox-LDL through decreasing ADMA concentration.     

Role of injury and phenotype shift of liver sinusoidal endothelial cells in the development of portal hypertension of cirrhosis in rats

AIM: To study the role of injury and phenotype shift of liver sinusoidal endothelial cells in the development of portal hypertension of liver cirrhosis in rats. METHODS: The rat liver cirrhosis model was established by peritoneal injection of dimethylnitrosamine (DMN) (at a dose of 10 mg·kg^-1, 3 times a week, for 4 weeks). The dynamic changes of liver cirrhosis were observed at different time points (1 day, 2 days, 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks and 8 weeks). The pressure of portal vein (Ppv), the expression of CD44, von Willebrand factor (vWF), endothelin-1 (ET-1) mRNA and endothelial nitric oxide synthase (eNOS) mRNA, the serum hyaluronic acid (HA) content and liver ET-1 content were measured. RESULTS: Compared with the normal control rats, CD44 positive staining was weak in the 1 day model rats, and the numbers of fenestrae of sinusoidal endothelial cells (SECs) rapidly decreased, but serum HA content rapidly increased (P<0.05). vWF positive staining in the 2-day model rats was stronger than that in normal control rats (P<0.05). There was a positive correlation between the Ppv and the vWF expression, serum HA content in the DMN-induced liver cirrhosis rats (P<0.05). Compared with the normal control rats, ET-1 mRNA expression increased in the 2-day and 3-day model rats, and ET-1 content lightly increased. eNOS mRNA expression was stronger in the 1-day, 2-day and 3-day model rats than that in normal control rats, meanwhile eNOS always expressed at a low level. CONCLUSION: The injury and phenotype shift of SECs is a pathological basis in the development of portal hypertension of DMN-induced liver cirrhosis in rats. Imbalance of ET-1 and NO production increases intrahepatic resistance, which plays an important role in the development of portal hypertension.