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1.
AIM:To evaluate effects of inhaled nitric oxide(iNO) on adhesion molecule CD11b expression on lung neutrophils in experimental meconium aspiration syndrome(MAS) rabbits treated with conventional mechanical ventilation under room air or 100%O2. METHODS:Animals were randomly allocated to 8 groups(n=48) of 6 each: two MAS model groups(under room air or 100%O2 without iNO treatment), 6 treatment groups were treated with continuous NO inhalation at a dose of 0.2×10-6mol/L, 0.33×10-6mol/L or 0.67×10-6mol/L respectively for 12 hours under room air or 100%O2. Mean systemic arterial pressure(SAP) and methemoglobin (MeHb) were performed at basement time, 0, 2, 4, 12 hours. Expression of CD11b on neutrophils in the bronchoalveolar lavage fluid(BALF) was detected with flow cytometry. RESULTS:SAP, MeHb at different time among different groups were within the normal scale. CD11b expression on the neutrophils in the BALF significantly decreased in groups of inhalation 0.33×10-6 mol/L or 0.67×10-6 mol/L NO, compared with the two MAS model groups. (x±s: under 21%O2, 0.33×10-6 mol/L NO, 121±20 υs 392±204; 0.67×10-6 mol/L NO, 112±30 υs 392±204;under 100%O2, 0.33×10-6 mol/L NO, 113±24υs293±65; 0.67×10-6 mol/L 102±114 υs293±65, P<0.05). 0.2×10-6mol/L NO inhalation did no effect on CD11b expression. (x±s:21%O2, 190±101 υs 392±204; 100%O2, 222±85 υs 293±65; P>0.05). No statistic difference was observed between groups inhaled 0.33×10-6 mol/L NO and 0.67×10-6mol/L NO. CONCLUSION:0.33×10-6 mol/L or 0.67×10-6 mol/L NO inhalation down-regulated the CD11b expression on the neutrophils in BALF to reduce the sequestration of neutrophils in rabbit lung.  相似文献   

2.
AIM:Tyrosinase gene was transfected into HEK293 cell as a reporter gene, it's property of synthesizing melanin, which can be examined by magnetic resonance imaging(MRI), is used to evaluate the tyrosinase gene's expression. The aim of this study was to search a way to evaluate the results of gene expression by MRI in vitro.METHODS:The plasmid of pcDNA3tyr which carried the full-length cDNA of tyrosinase gene was transfected into HEK293 cell by lipofectin. To observe the MRI signals of expressed melanin, the transfected cells were scanned by MRI sequences of T1WI, T1WI/SPIR and T2WI. On the other hand, fontana stain was used to search for melanin granules in transfected cells, RT-PCR method was used to search for cDNA of tyrosinase gene.RESULTS:(1) Plasmids of pcDNA3tyr could be transfected into HEK293 cells and could synthesize a large amount of melanin. The synthetic melanins of 106 cells, which had been transfected 5μg, 10μg, 20μg plasmids of pcDNA3tyr separately, were all sufficient to be detected by MRI and appeared high signal in MRI T1WI、T1WI/SPIR、T2WI sequences. The signal intensities of MRI imaging were related to the amounts of transfected plasmids positively. (2) The melanin granules could be found in HEK293 cells by Fontana stain. (3) The cDNA fragment of tyrosinase gene could be detected in transfected HEK293 cells by RT-PCR.CONCLUSION:The fact that MRI could detect the synthet ic melanin of HEK293 cells, which controlled by expression of exogenous gene, demonstrates that medical imaging connecting with molecular biology technology can evaluate the result of gene expression in vitro.  相似文献   

3.
AIM: To investigate the diffusion effect of malignant tumor in cervix by diffusion weighted imaging (DWI) of magnetic resonance imaging (MRI).METHODS: Routine MRI sequences and axial diffusion weighted sequences were performed in the cases of cervical cancer and endometrial carcinoma. Normal cervixes and endometria were served as controls. The ADC values of cervical cancer and normal cervix, endometrial carcinoma and normal endometrium were measured and analyzed respectively.RESULTS: (1)The ADC values in 37 cases of cervical cancer and normal cervix of 16 volunteers were (0.92±0.20)×10-3 mm2/s and (1.26±0.24)×10-3 mm2/s respectively, with statistically significant difference between cervical cancers and normal cervixes (P<0.01). (2)The ADC values in 14 cases of endometrial carcinoma and normal endometrium of 14 volunteers were (0.87±0.17)×10-3 mm2/s and (1.34±0.26)×10-3 mm2/s respectively, with statistically significant difference between endometrial carcinoma and normal endometria (P<0.01).CONCLUSION: The diffusion effects of cervical cancer and endometrial carcinoma were different from those of normal cervical tissues. The DWI of 3.0T MRI may be used to quantitatively determine the limitation of diffusion effect in the malignant tumor in cervix by measuring the ADC value.  相似文献   

4.
AIM: To investigate the synergistic effects of ampelopsin (AMP) and a chemotherapeutic drug mitomycin (MMC) on the proliferation of gastric cancer cell line SGC-7901.METHODS: SGC-7901 cells were cultured in vitro and divided into 4 groups: control group, AMP group, MMC group and AMP+MMC group. Cell proliferation was measured by MTT method. The apoptotic index was examined by flow cytometry. The expression of apoptotic proteins, Bcl-2 and survivin, was detected by Western blotting.RESULTS: AMP at the concentrations ranging from 2.2 mg/L to 14.84 mg/L exerted inhibitory effect on the growth of SGC-7901 cells. Cell proliferation in AMP (14.84 mg/L) group was inhibitory by (60.85±1.13) %, significantly higher than that in control group (P<0.05). The inhibitory rates of cell proliferation varied from (17.40±0.30) % to (72.23±1.36) % when the concentrations of MMC increased from 1×10-3 g/L to 1×10-2 g/L. AMP combined with MMC showed a synergistic effect on the growth of SGC-7901 cells. The inhibitory rates of cell proliferation varied from (21.83±2.50) % to (46.70±1.45) % when the concentrations of MMC increased from 1×10-3g/L to 5×10-3g/L. The inhibitory effect of AMP plus MMC was higher than that of MMC or AMP alone. The protein levels of Bcl-2 and survivin were inhibited in AMP group, MMC group and AMP+MMC group, and were significantly lower in AMP+MMC group than those in AMP group or MMC group.CONCLUSION: AMP enhances the inhibitory effect of MMC on the growth of SGC-7901 cells. The mechanism is related to the inhibition of apoptotic protein expression.  相似文献   

5.
AIM: To explore the role of basic-fibroblast growth factor (bFGF) in the development of pulmonary hypertension induced by hypoxia. METHODS: 1) The pulmonary arteries of SD rats with hypoxia for one and two weeks were isolated, from which the total RNA were extracted by acid guanidinium thiocyanate-phenol-chlorform .Then the levels of mRNA were measured by RT-PCR. 2) About 3mm-long arterial rings cut from SD rat pulmonary arterial stem were suspended between stainless steelhooks in chamber with warmed (37℃) Kreb's solution. Different concentrations of bFGF were added in a cumulative fashion into the chamber where the rings were suspended. The cumulative concentration response curve was obtained. RESULTS: 1)The levels of bFGF mRNA in pulmonary artery of rats with hypoxia were increased significantly compared with those that without hypoxia (2578±384 counts·min-1 (control) vs 5303±756 (hypoxia) for 1 week and 4054±547 (hypoxia) for 2 weeks, P all ＜0.05). 2) bFGF at concentrations ranged from 5.56×10-10~2.78×10-7mol/L caused dose-dependent contraction of vessel rings of rat pulmonary artery (r=0.695,P＜0.05), with EC50 being 2.62×10-7mol/L. CONCLUSION: bFGF may play an important role in the hypoxic pulmonary hypertension.  相似文献   

6.
AIM: To investigate the roles of pioglitazone on differentiation and expression of GILZ in 3T3-L1 pre-adipocytes. METHODS: The morphological changes during 3T3-L1 cell differentiation were observed. The cells were treated with pioglitazone at concentrations of 1×10-4～1×10-2 mmol/L for 48 h, then the relative content of triglyceride were analyzed by oil red O staining at 2nd, 4th and 6th day during adipogenesis. The mRNA expression of peroxisome proliferator-activated receptor γ2 (PPARγ2) and lipoprotein lipase (LPL) was measured by real-time PCR. GILZ protein expression was determined by Western blot after the cells were treated with pioglitazone at concentrations of 1×10-4 ～1×10-2 mmol/L for 48 h.RESULTS: Oil-red O staining showed that the relative contents of triglyceride in adipocytes were increased with the increase in the pioglitazone concentration. Compared with the control, the relative contents of triglyceride in group 1×10-3 mmol/L and group 1×10-2 mmol/L were significantly increased (P < 0.05). The mRNA expression of PPARγ2 and LPL was also increased with the increase in the pioglitazone concentration. When pioglitazone concentration was more than 1×10-3 mmol/L, compared with the control, the mRNA expression of PPARγ2 and LPL significantly increased (P < 0.01). The protein expression of GILZ was decreased with the increase in the pioglitazone concentration.CONCLUSION: Pioglitazone down-regulates GILZ expression, and up-regulate PPARγ2 expression and the downstream functional factor such as LPL.  相似文献   

7.
AIM: To examine and compare the ability of serum IgA 1, from both the patients with IgA nephropathy(IgAN) and the healthy control, to bind to human mesangial cells(HMC). METHODS: Serum IgA was isolated with jacalin column, heated to aggregated form(IgA1) and labeled with [125I]. Binding capacity of IgA1 to primary HMC was evaluated by radioligant binding assay, specificity of binding was determined by competitive inhibition, and relative affinities was compared by cross competitive inhibition. RESULTS: Both IgA1 from normal control and patients with IgAN bound to MC in a dose-dependent, saturatable manner, but the binding of IgA1 from patients was saturated at approximately 200 pmol while that from healthy was at 400 pmol. The Scatchard analysis revealed a Kd of(8.9±2.1)×10-8 mol/L for patient' s IgA1 versus(4.3±1.2)×10-7mol/L for normal IgA1(P<0.05). Competition inhibition showed that both serum albumin and IgG could not block the binding of IgA1 to HMC while mIgA 1 could partially block that. Cross competition inhibition demonstrated that patient' s IgA1 blocked normal IgA1 binding significantly(P<0.01), however, normal IgA1 was unable to inhibit the binding of patient' s IgA1. CONCLUSIONS: ①There are IgA binding proteins or receptors on mesangial cells. ②IgA1 from patients with IgAN has a higher binding capacity than that from healthy.  相似文献   

8.
AIM: To synthesis and characterize a multi-functional siRNA delivery agent with effective therapeutic effects and MR-tracing ability for programmed death ligand-1 (PD-L1) positive gastric cancer SGC-7901 cell line. METHODS: The characterization, binding ability, cytotoxicity, transfection efficiency and cellular internalization of the polyplex were determined. The PD-L1 knockdown effect was analyzed, and cytokines secreted by cocultured T cells were measured.RESULTS: We developed folic acid (FA)-PEG-SS-PEI-SPION as siRNA delivery agent for PD-L1 knockdown. At N/P ratio of 10, the FA-PEG-SS-PEI-SPION bound PD-L1 siRNA to form polyplex in a diameter of (116.7±2.5) nm with zeta potential of (9.14±0.80) mV. Transfection efficiency of the targeted polyplex was (95.06±0.44)%, compared with (93.87±1.05)% of the untargeted polyplex. Mean fluorescence intensity of the targeted polyplex was 1 892.67±81.51, significantly higher than 1 324.33±186.58 of the untargeted. The cellular magnetic resonance (MR) imaging showed the polyplex also acted as T2 weighted contrast agent for cancer MR imaging. The relative mRNA level of PD-L1 in polymer/siRNA-2 treatment group was (9.07±0.79)%. Decreased protein expression of PD-L1 was showed by Western blot. The secretion levels of IFN-γ and TNF-α in cocultured T cells increased, while that of IL-10 decreased. CONCLUSION: Our findings highlighted the potential of the multifunctional theranostic nanoparticles for effective targeting PD-L1 knockdown therapy and MR imaging diagnosis in gastric cancers.  相似文献   

9.
AIM: To study the effects of cyproheptadine (Cyp) and anisodamine (Ani) on the changes of intracellular free Ca2+ concentration ([Ca2+]i) induced by tumor necrosis factor (TNFα) in single endothelial cells, and to explore the mechanisms of TNFα mediated shock and antishock actions of Cyp and Ani. METHODS: Human umbilical vein endothelial cell strains (ECV304) were seed in 35 mm tissue culture dish with 2 mL DMEM culture medium. The cultured cells were loaded by Fluo-3/AM. The spatial distribution and the dynamic changes of [Ca2+]i in single endothelial cell was determined by laser scanning confocal microscopy (LSCM). RESULTS: [Ca2+]i in single endothelial cell after stimulation of TNFα rapidly increased in a dose-dependent manner and approached the peak value within 60 seconds, afterwards, decreased and kept above the basal level. The confocal scanning image showed that [Ca2+]i elevation was more obvious in nuclear than in cytoplasma, and decreased slowly. Cyp (3×10-5, 6×10-5 mol/L) and Ani (2×10-5, 4×10-5 mol·L-1) markedly inhibited TNFα (1.2×10-9 mol·L-1)-induced [Ca2+]i elevation. CONCLUSIONS: TNFα markedly induces elevation of [Ca2+]i in single endothelial cell, it may be an important mechanism of TNFα-induced shock and tissue injury. Cyp and Ani obviously suppress TNFα-induced [Ca2+]i elevation, which probably is one of the mechanisms of their antishock effects.  相似文献   

10.
AIM: To investigate the effects of nicotine on activation of PMNs, adhesion of PMNs-HUVEC and expression of ICAM-1 mRNA in HUVEC. METHODS: Activation of PMNs was measured by detecting the activity of β-glucuronidase and lysozym of PMNs. Adhesion of PMNs and HUVEC was observed. Northern blot was conducted for quantitating ICAM-1 mRNA. RESULTS: Nicotine could increase the activity of β-g [(8.76± 1.01)μg/107·h vs(14.87±2.00)μg/107·h,P<0.05]and Lysozym [(20.0±1.5)μg/107·h vs(36.5±4.4)μg/107·h,P<0.05], and also could promote adhesion of PMNs-HUVEC(38.5±9.8 vs 61.0±4.4,P＜0.05). The expression of ICAM-1 mRNA was induced by nicotine in dose-dependent fashion (10-5-10-3mol/L).After a 2 h treatment of HUVEC with nicontine(10-4mol/L), the level of ICAM-1 mRNA is above the control(1.23 vs 1.63) and the highest level (2.03) is at a 12 h treatment. 764-3 can obviously counteract the above effect of nicotine. CONCLUSIONS: Nicotine could activate PMNs, enhance adhesion of PMNs-HUVEC and increase the expression of ICAM-1 mRNA in HUVEC.  相似文献   

11.
AIM: To study the effects of hemorrhagic shock on BKCa channel tyrosine phosphorylation in rat superior mesenteric artery and the role of nitric oxide (NO) in BKCa channel tyrosine phosphorylation. METHODS: The hemorrhagic shock model [(35±5)mmHg] was established in rats and the whole lysate of superior mesenteric artery were extracted and analyzed by immune precipition (IP) and immunoblotting. The tyrosine phosphorylation levels of BKCa channel alpha-subunit in mesenteric artery in hemorrhagic shock rats were investigated, and the modulation of BKCa channel alpha-subunit tyrosine phosphorylation by NO and its dose-and time-dependended relationships were observed. RESULTS: The tyrosine phosphorylation level of BKCa channel alpha-subunit in mesenteric artery in rats increased significantly after hemorrhagic shock 2 h and 4 h (P<0.01 ), and L-arginine (5×10-5-5×10-4 mol/L) up-regulated BKCa channel alpha-subunit tyrosine phosphorylation in primary cultured VSMC in a 30 min incubation and without significant decrease after 2 h; L-arginine induced BKCa channel alpha-subunit tyrosine phosphorylation in a dose-dependent manner. CONCLUSION: Hemorrhagic shock enhances BKCa channel tyrosine phosphorylation in resistant artery in rats, and NO is involved in this process.  相似文献   

12.
WU Di  ZHANG Cui  LIANG Ren 《园艺学报》2004,20(8):1481-1484
AIM: To elucidate the effects of platelet-activating factor (PAF) on eosinophil activation and the action of dexamethasone or theophylline during this process. METHODS: Eosinophils (EOS) from the peripheral blood of normal subjects were isolated. The hypodense eosinopil (HE) and normodense eosinophil (NE) were studied with electron microscopy. The effects of PAF on eosinophil activation and the action of dexamethasone or theophylline during the above process were measured. RESULTS: Hypodense eosinophil had significantly smaller individual granules than normodense eosinophil had. PAF induced eosinophil peroxidase release, and generated. Eosinophils incubated with 10-8 mmol/L PAF and 10-5 mmol/L dexamethasone released (101.17±10.32) mg/L eosinophil peroxidase (P<0.05). Eosinophils incubated with 10-9 mol/L PAF and 10-5 mmol/L dexamethasone caused a decrease in eosinophil peroxidase (110.85±4.16) mg/L and induced the generation of hypodense eosinophil (17.87%±2.16%). Eosinophils incubated with 10-8 mmol/L PAF and 10 mg/L theophylline released (100.53±9.65) mg/L eosinophil peroxidase (P<0.05). Eosinophils incubated with 10-9 mol/L PAF and 10 mg/L theophylline caused a similar decrease in eosinophil peroxidase (106.94±10.11) mg/L and induced the generation of hypodense eosinophil (14.08%±2.42%). CONCLUSIONS: Eosinophil degranulation is one of the reasons by which hypodense eosinopils develop. PAF induced eosinophil degranulation, so generated hypodense eosinopils. Dexamethasone and theophylline inhibited above effects.  相似文献   

13.
AIM:To observe the effects of the combination of positive end expiratory pressure (PEEP) and 80×10-6 nitric oxide (NO) inhalation on oleic acid induced acute lung injury (ALI) in canine.METHEDS:30 dogs were divided into 6 groups. Oleic acid was injected through Swan-Ganz catheter to induced ALI. Pulmonary and systemic hemodynamics,blood gas were measured in dogs before and after injection of oleic acid and the period of inhaled NO for 1-6 h. The methemoglobin(MHb) concentrations were measured. Histology and ultrastructure of the lung tissue were observed. RESULTS:(1) The combination of PEEP and 80×10-6 NO inhalation rapidly reduced mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance (PVR), increased PaO2/FiO2, reduced A-aDO2 without inducing significant change on systemic hemodynamics. Arterial blood levels of MHb did not change significantly. (2)The combination group was showed the lightest ALI change by HE stain and electron microscopy. CONCLUSION:The combination of PEEP and inhalation of 80×10-6 NO significantly and rapidly increased PaO2/FiO2 without producing lung injury induced by high FiO2 and high PEEP.  相似文献   

14.
AIM: To study the effect of thyroid hormone on the expressional change of myosin heavy chain(MHC) gene in cardiomyocyte induced by angiotensinⅡ(AngⅡ) and its potential mechanism. METHODS: Cardiac myocyte was cultured according to the method of Simpson. 10-8 mol/L T3 and 10-7 mol/L AngⅡ were added to the culture medium, respectively or synchronously. After 48 h, the expression of α and β-MHC mRNA in myocytes were detected by RT-PCR. The protein kinase C activation were detected by PepTag non-radioactive PKC assay. The incorporation of -Leucine and [3H]-thymine to test the protein and DNA synthesis in myocytes were also performed. RESULTS: AngⅡalone increased the incorporation of [3H]-Leucine of myocytes while it had no effect on the incorporation of [3H]-thy mine. The expression of β-MHC mRNA was increased and the expression of α-MHC mRNA was decreased significantly at the condition of AngⅡ. The enhanced PKC activation was induced by AngⅡalso. When AngⅡand T3 were added to the culture medium synchronously, though the incorporation of [3H]-leucine and [3H]-thymine were not changed compared with AngⅡ treated alone. The α-MHC mRNA expression was increased and the β-MHC mRNA expression was decreased significantly. The PKC activation of the myocytes also was decreased. CONCLUSIONS: T3 inhibited the expressional change of myosin heavy chain gene in cardiac myocytes induced by AngⅡ. The effect of T3 on the change of PKC activation in cardiac myocytes may be one of its mechanisms.  相似文献   

15.
AIM:To establish cell line FL-POLκ- and to study the role ofPOLκ(polymerase kappa) on genetic stability.METHODS:A mammalian expression vector expressing antisense POLκ gene fragment pMAMneo -amp--POLκ was constructed by cloning the 1 690-1 918 fragment of POLκ gene into the mammalian expression vector pMAMneo-amp- in antisense orientation. FL cells were fransfected with this antisense RNA expressing vector and selected by G418. Based on the shuttle-plasmid pZ189, the mutation assay was made.RESULTS:The spontaneous mutation frequency of supF tRNA gene in the plasmid replicated in the FL- POLκ- was 11.2×10-4, while it was 4.9×10-4 and 3.7×10-4 in the control cells FL and FL-M, respectively.CONCLUSION: POLκ playes an important role in maintenance of genetic stability.  相似文献   

16.
AIM:To investigate the mechanism of angiotensinⅡ (AngⅡ)/angiotensinⅡ type 1 receptor (AT1R) pathway activating protein phosphatase 2A (PP2A) which leads to down-regulation endothelial nitric oxide synthase (eNOS) phosphorylation level in mesenteric arteries of rats. METHODS:The mesenteric arteries of adult male SD rats (weighing 160~180 g; n=90) were isolated under aseptic conditions. Firstly, to determine the effect of angiotensinⅡ down-regulated eNOS (Ser1177) phosphorylation level, the mesenteric arteries were randomly divided into normal control (control) group and AngⅡ group. The mesenteric arteries in AngⅡ group were incubated with AngⅡ at 1×10-7 mol/L, 1×10-6 mol/L and 1×10-5 mol/L for 6 h, 12 h and 24 h, respectively. Secondly, to investigate the molecular mechanism by which angiotensinⅡ activated PP2A leading to down-regulation eNOS (Ser1177) phosphorylation level, the mesenteric arteries were randomly divided into control group, AngⅡ group and candesartan (CAN; a specific AT1R blocker)+AngⅡ group. The mesenteric arteries were pretreated with 1×10-5 mol/L CAN for 1 h, then incubated with 1×10-7 mol/L AngⅡ for 12 h in CAN+AngⅡ group. The protein levels of eNOS, p-eNOS (Ser1177), PP2Ac, p-PP2Ac (Tyr307) and protein phosphatase 2A inhibitor 2 (I2PP2A) in the arteries were determined by Western blot. The activity of PP2A in the arteries was detected by PP2A activity kit. RESULTS:Compared with the control group, the protein level of p-eNOS (Ser1177) in the mesenteric arteries was decreased after incubated with AngⅡ for 6 h, 12 h and 24 h (P<0.05). The decreasing tendency of p-eNOS (Ser1177) showed concentration-dependently, especially in 12 h and 24 h groups. The expression of eNOS protein showed no significant difference in each group. Compared with the control group, the mesenteric arteries of the rats were incubated with AngⅡ at 1×10-7 mol/L for 12 h in vitro, the protein levels of p-eNOS (Ser1177) were down-regulated (P<0.05); pretreatment with CAN significantly increased the protein level of p-eNOS (Ser1177) (P<0.05); the protein levels of eNOS showed no significant difference in each group. Compared with the control group, the protein levels of p-PP2Ac (Tyr307) and I2PP2A were decreased after the mesenteric arteries were treated with AngⅡ at 1×10-7 mol/L for 12 h (P<0.05). Candesartan pretreatment restored the protein levels of p-PP2Ac (Tyr307) and I2PP2A (P<0.05), however the expression of PP2Ac protein showed no significant difference in each group. Compared with the control group, the activity of PP2A was increased in the mesenteric arteries incubated with AngⅡ at 1×10-7 mol/L for 12 h (P<0.05). Candesarten pretreatment inhibited the activity of PP2A significantly (P<0.05). CONCLUSION:AngⅡ increases PP2A activity via AT1R pathway, thus leading to down-regulation eNOS (Ser1177) phosphorylation level in mesenteric arteries. The molecular mechanism of PP2A activation may be associated with decreasing the protein levels of p-PP2Ac (Tyr307) and I2PP2A.  相似文献   

17.
AIM: To investigate the effects of Rho-associated kinase (ROCK) and protein kinase C (PKC) on the relaxation of isolated rat aortic rings induced by nifedipine and the mechanisms. METHODS: The changes of tension in vascular rings induced by nifedipine under the basic condition and pre-contracted by norepinephrine (NE, 10-6 mol/L) or KCl (60 mmol/L) were observed. The effects of ROCK and PKC on the vasodilation induced by nifedipine were studied using the vascular ring perfusion device. RESULTS: Nifedipine (10-10 mol/L, 10-9 mol/L, 10-8 mol/L, 10-7 mol/L, 10-6 mol/L and 10-5 mol/L) had no significant relaxation effect on isolated aortic rings under basic condition. Nifedipine induced dose-dependent relaxation in both endothelium-intact and endothelium-denuded aortic rings pre-contracted by 10-6 mol/L NE and 60 mmol/L KCl (P<0.05). No obvious difference between endothelium-intact group and endothelium-denuded group was observed. After incubation of the PKC inhibitor staurosporine (STA, 10-8 mol/L) and PKC agonist phorbol 12-myristate 13-acetate (PMA, 10-7 mol/L), STA increased the relaxation induced by nifedipine, while PMA reduced the effect of nifedipine on blood vessels (P<0.05). After the incubation of the ROCK inhibitor fasudil (10-6 mol/L) and ROCK agonist angiotensin Ⅱ (Ang-Ⅱ, 10-9 mol/L), fasudil increased the relaxation induced by nifedipine, while Ang-Ⅱ reduced the effect of nifedipine on blood vessels (P<0.05). The relaxation induced by nifedipine was not statistically inhibited by BaCl2 (10-4 mol/L), tetraethylammonium (10-3 mol/L), glibenclamide (10-5 mol/L) and 4-aminopyridine (10-3 mol/L). In calcium-free and high-potassium solution, pre-treatment with nifedipine (10-9 mol/L, 5×10-8 mol/L and 10-6 mol/L) inhibited calcium-induced contraction of the aortic rings (P<0.05). However, nifedipine pre-treatment did not affect the contraction induced by NE in Ca2+-free medium. CONCLUSION: Nifedipine exhibits vasodilatation effect in a dose-dependent manner and the vasodilatation activity is endothelium-independent. The vasodilatation effect of nifedipine may be related to the inhibition of extracellular calcium influx, and inhibition of PKC and ROCK enhances the vasodilatation effect of nifedipine.  相似文献   

18.
AIM:To explore the effects of hydrogen sulfide (H2S) on proliferation of vascular smooth muscle cells (VSMC) stimulated by endothelin (ET-1, 10-7mol/L) and mitrogen-activated protein kinase (MAPK) activity in VSMCs.METHODS:Cultured VSMCs were divided into six groups: (1) control group, (2) serum group, (3) endothelin group, (4) NaHS groups, (5) serum+NaHS group, and (6) endothelin+NaHS group. VSMC proliferation was measured by[3H]-TdR incorporation and MAPK activity in VSMC was determined by radioactivity assay.RESULTS:ET-1 increased VSMC[3H]-TdR incorporation by 2.39 times (P＜0.01) and MAPK activity by 1.62 times(P＜0.01), as compared with control. H2S (5×10-5-5×10-4mol/L) decreased VSMC[3H]-TdR incorporation and MAPK activity by 16.8%-37.4% and 7.4%-33.6%, respectively (P<0.05 or P＜0.01).CONCLUSION:This study demonstrates that H2S inhibits ET-1-induced proliferation of VSMC, which might be mediated by the inhibition of MAPK.  相似文献   

19.
AIM: The objectives of the present study were to examine the effect of iron on relaxation of isolated rat aortic rings, and to elucidate the underlying mechanism. METHODS: The thoracic aortic rings of male Sprague-Dawley rats were mounted on bath system. Vasodilatation of aortic rings preconstricted with 10-6 mol/L of phenylephrine (PE) was measured. RESULTS: (1) Exposure of endothelium-intact aortic rings to ferric ammonium citrate (FAC) for 30 min caused a significant reduction in the relaxation response to acetylcholine (ACh). Pretreatment with L-arginine (L-Arg) before incubation with FAC did not reverse the inhibition of relaxation response to ACh completely. (2) In endothelium-intact aortic rings, L-Arg relaxed the PE preconstricted vessels. Exposure to FAC for 30 min caused the decrease in the relaxation response to L-Arg. There was no difference in the relaxation response to nitric oxide donor, sodium nitroprusside, between endothelium-denuded arteries treated with or without FAC. (3) Dimethyl sulfoxide had no effect on the inhibition of relaxation to ACh by FAC in endothelium-intact rings. Pretreatment of arteries with glutathione and catalase prevented the decrease in relaxation responses to ACh induced by FAC. (4) The nitric oxide synthase activity was (56.49±2.49)×103U/g protein in normal aorta with endothelium, while after incubation with FAC for 30 min, it reduced to (25.15±5.75)×103U/g protein ( P< 0.05). CONCLUSION: Inactivation of nitric oxide synthase and decrease in intracellular glutathione level might mediate iron-induced inhibition of arterial relaxation responses to ACh.  相似文献   

20.
AIM:To investigate the effect of endothelin (ET), angiotensin II (AngII) and homocysteine (Hcy) on C-type natriuretic peptide (CNP) synthesis and release. METHODS: Human endothelial cell was cultured; CNP was measured by radioimmunoassay method. RESULTS: ET and AngII could augment CNP synthesis in human endothelial cells. Compared with control group, 10-9,10-8,10-7 mol/L ET and Ang II increased CNP content of endothelial cells by 1%(P＞0.05), 49%(P＜0.05),117%(P＜0.01) and 137% (P＜0.01),165%(P＜0.01),201%(P＜0.01),respectively. A great dose of ET and Ang II also stimulated CNP release from cultured human endothelial cells. Hcy had no effect on CNP synthesis, but 10-9,10-8,10-7 mol/L Hcy enhanced CNP release from cultured human endothelial cells by 17%(P＞0.05),84%(P＜0.01) and 555%(P＜0.01), respectively. CONCLUSION: ET, AngII and Hcy might be involved in the synthesis and release of human endothelial cell CNP.Fig 1 Time-course of CNP syntheis and release in cultured human endothelial cell ( ±s,n=6)  相似文献   

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