柚皮素通过PI3K/Akt通路拮抗血小板聚集的体外研究

目的:探讨柚皮素拮抗二磷酸腺苷(ADP)诱导的血小板聚集的作用及机制。方法:采用血小板聚集仪观察不同浓度柚皮素对ADP诱导的大鼠血小板聚集的影响。采用荧光显微镜观察柚皮素对血小板在固化纤维蛋白原上扩展功能的影响。采用Western blot检测磷脂酰肌醇3-激酶(PI3K)表达及蛋白激酶B(Akt)磷酸化水平。结果:柚皮素能剂量依赖性地抑制ADP诱导的体外血小板聚集,其半数抑制浓度(IC_(50))值为(132.1±31.7)μmol/L。柚皮素灌胃给药,对ADP诱导的大鼠体内血小板聚集也有明显的抑制作用。柚皮素还能显著抑制血小板在固化纤维蛋白原上的扩展。Western blot结果显示,柚皮素能明显抑制ADP刺激的PI3K表达和Akt磷酸化同时,PI3K广谱抑制剂LY294002能增强柚皮素对Akt磷酸化的抑制作用。结论:柚皮素可能通过抑制血小板PI3K/Akt信号通路发挥抗血小板聚集的作用。     

粒细胞白血病患者环核苷酸代谢的研究

通过对２１例粒细胞白血病患者血浆环－磷酸腺苷（ｃＡＭＰ）含量、腺苷酸环化酶（ＡＣ）、环腺苷酸磷酸二酯酶（ＰＤＥ）比活性和环－磷酸鸟苷（ｃＧＭＰ）含量进行检测，并与１８例非白血病患者和２２例正常人血浆ｃＡＭＰ、ｃＧＭＰ含量和ＡＣ、ＰＤＥ比活力进行比较，发现急性和慢性粒细胞性白血病组的ｃＡＭＰ水平显著低于正常对照组（Ｐ〈０．０１）、ＡＣ比活力也显著低于正常对照组（Ｐ〈０．０１）、ｃＧＭＰ水平显著高于正     

PDE5抑制剂与cGMP信号通路相关疾病的研究进展

磷酸二酯酶5(phosphodiesterase 5,PDE5)抑制剂通过阻断环磷酸鸟苷(cyclic guanosine monophos?phate,cGMP)的分解,使包括一氧化氮(nitric oxide, NO)在内的血管舒张介质作用延长,从而导致阴茎和肺的血管舒张.PDE5主要在阴茎海绵体和肺血管中发现,所...     

磷酸二酯酶及其抑制剂在心力衰竭中的研究现状

心力衰竭简称心衰(heart failure,HF),是由于结构或功能性心脏异常引起心室充盈和(或)射血能力受损的一组慢性进行性临床综合征,其主要临床特征是肺循环淤血、心排血量降低和体循环淤血,表现为左心室射血分数(left ventricular ejection fraction, LVEF)降 低(HF with...     

柚皮素通过抑制NF-κB-iNOS/COX-2通路减轻小鼠糖尿病肝损伤

目的：探讨核因子(NF-κB)-诱导型一氧化氮合酶(i NOS)/环加氧酶2(COX-2)信号通路在柚皮素治疗减轻小鼠糖尿病肝损伤中的作用。方法：将昆明小鼠分为正常对照组、糖尿病肝损伤模型组、低剂量(25 mg·kg^-1·d^-1,灌胃)柚皮素治疗组及高剂量(75 mg·kg^-1·d^-1,灌胃)柚皮素治疗组,每组10只。长期高能量饮食联合多次小剂量链脲菌素(STZ;40 mg·kg^-1·d^-1×5 d,腹腔注射)建立小鼠糖尿病肝损伤模型。HE染色观察肝脏形态学变化;生化试剂盒检测小鼠血脂及肝功能改变;每周监测空腹血糖(FBG)水平;q RT-PCR检测肝脏NF-κB、iNOS和COX-2的mRNA表达;Western blot法检测肝脏NF-κB、iNOS和COX-2蛋白表达。结果：给予STZ 7 d,小鼠FBG水平持续高于11.1 mmol/L,4周后肝脏病理变化及肝功能检测提示出现肝损伤。再过4周(即实验结束时),模型组小鼠肝细胞内可见脂肪变性,还伴有炎...     

内生致冷原作用机制的研究

家兔侧脑室内注射纯化内生致冷原(endogenous cryogen,EC)引起直肠温度下降和耳皮肤温度上升,其反应与静脉注射的情况相似,但直肠温度降低更加迅速,所用剂量仅为静脉注射达到同样效应时的1/80。静脉注射EC降温反应过程中,体温下降至最低点时脑脊液cAMP浓度显著下降,而cGMP浓度没有显著改变,血浆cAMP和cGMP浓度均显著升高;体温回升至正常水平时脑脊液、血浆cAMP和cGMP浓度均与对照组无显著差异。本实验结果提示:(1)EC的主要作用部位可能是中枢神经系统;(2)cAMP可能参与EC降温反应的中枢机制。     

柚皮素通过ROS/P38-MAPK信号通路调控肺癌A549细胞增殖及凋亡

目的:探讨柚皮素调控A549细胞增殖及凋亡的分子机制.方法:培养A549细胞,通过CCK-8法检测不同浓度的柚皮素(0、30、60、90、120 μmol/L)对A549细胞增殖的影响;流式细胞术检测各组细胞凋亡及ROS含量;WST-8法检测SOD活性以及硫代巴比妥酸法(TBA检测法)检测MDA含量;Western b...     

柚皮素通过抑制TGF-β1/smad信号传导通路缓解糖尿病肾病大鼠肾损伤

目的探讨柚皮素对糖尿病肾病大鼠肾脏的保护作用及其对TGF-β1/smad信号传导通路的影响。方法将糖尿病肾病模型大鼠随机分为糖尿病肾病组和糖尿病肾病+柚皮素组,用药治疗6周。检测大鼠24 h尿蛋白定量、肌酐清除率和肾脏指数;HE染色观察肾组织形态和检测肾小球面积;实时荧光定量PCR检测Ⅳ型胶原、纤维连接蛋白、TGF-β1、Smad2和Smad7 mRNA的表达;Western blot检测Ⅳ型胶原、纤维连接蛋白、TGF-β1、smad7、总smad2和磷酸化smad2蛋白。结果糖尿病肾病组大鼠24 h尿蛋白(P0.01)和肾脏指数(P0.01)显著升高,肌酐清除率明显下降(P0.01),肾小球明显肥大(P0.05),Ⅳ型胶原和纤维连接蛋白的mRNA水平和蛋白表达量均升高,TGF-β1和磷酸化smad2蛋白的表达量均升高,smad7蛋白表达量降低;经柚皮素50 mg/kg治疗后能明显降低糖尿病肾病大鼠的24 h尿蛋白(P0.01)和肾脏指数(P0.05),提高肌酐清除率(P0.05),减轻肾小球肥大(P0.05),Ⅳ型胶原和纤维连接蛋白的mRNA水平和蛋白表达量降低,TGF-β1和磷酸化smad2蛋白的表达量均降低,smad7蛋白表达量升高。结论柚皮素可能通过调控糖尿病肾病肾组织TGF-β1/smad信号通路表达,减轻肾脏病理损害。     

葡萄籽原花青素体外抗血小板聚集的机制研究

目的: 研究葡萄籽原花青素(PC)体外抗血小板聚集的可能机制。方法: 应用血小板聚集仪研究PC、二亚苯基碘鎓(DPI,非特异性NADPH氧化抑制剂)和夹竹桃麻素(apocynin,特异性NADPH氧化酶抑制剂)对胶原诱导的健康志愿者血小板最大聚集率的影响。用化学发光仪检测PC对血小板NADPH氧化酶活性、一氧化氮(NO)含量和超氧阴离子(O₂^-·)水平的影响。用流式细胞术观察PC对血小板活化标志物PAC-1和CD62P表达率的影响。结果: PC(100 μmol/L)、apocynin(10 μmol/L)和DPI(100 μmol/L )均可显著抑制胶原蛋白诱导的血小板最大聚集率(P<0.01)。胶原蛋白激活的血小板NO含量显著降低,O₂^-·含量显著增加,100 μmol/L PC可使二者明显恢复(P<0.05)。添加了100 μmol/L PC的样本中,血小板NADPH氧化酶活性受到明显的抑制(P<0.01),血小板PAC-1 和CD62P表达率也显著降低(P<0.05)。结论: 葡萄籽原花青素可能通过抑制NADPH氧化酶的活性,进而影响血小板NO和O₂^-·含量,在一定程度上阻断血小板活化过程,最终达到抗血小板聚集的作用。     

右美托咪定通过cGAS-STING通路介导的免疫调控机制对胃癌细胞恶性生物学行为的影响

目的：探究右美托咪定（DEX）通过环磷酸鸟苷-磷酸腺苷合酶-干扰素基因刺激因子（cGAS-STING）通路介导的免疫调控机制对胃癌（GC）细胞恶性生物学行为的影响。方法：将GC细胞株MGC-803随机分为对照组（Control组,空白培养基处理）、DEX低浓度组（DEX-L组,1 ng/ml）、DEX中浓度组（DEX-M组,10 ng/ml）、DEX高浓度组（DEX-H组,100 ng/ml）和DEX高浓度+cGAS抑制剂RU.521组（DEX-H+RU.521组,100 ng/ml DEX+1.0μmol/L RU.521）。CCK-8法检测细胞增殖情况。细胞划痕实验检测各组细胞的迁移能力。Transwell实验检测各组细胞的侵袭能力。流式细胞术检测细胞凋亡率。ELISA检测细胞中IL-2、干扰素-γ(IFN-γ)、肿瘤坏死因子α(TNF-α)水平。实时荧光定量PCR(RT-qPCR)法检测细胞cGAS、STING、Ⅰ型干扰素（IFN-Ⅰ）mRNA的表达水平。Western blot检测细胞cGAS、STING、Bax、细胞周期蛋白D1(CyclinD1)、基质金属蛋白酶9(MMP9...     

Effect of stress adaptation on cyclic nucleotide content in myocardial tissue during acute ischemia/reperfusion

We studied the effect of adaptation to chronic immobilization stress on the contents of cyclic adenosine monophosphate and cyclic guanosine monophosphate in myocardial tissue during coronary occlusion and reperfusion. The contents of cyclic adenosine monophosphate and cyclic guanosine monophosphate in the ischemic area and nonischemic myocardium of unadapted rats increased during coronary artery ligation for 10 min. Reperfusion for 10 min was followed by an increase in the content of cyclic adenosine monophosphate. During coronary occlusion, the content of cyclic adenosine monophosphate in the myocardium of stress-adapted rats increased less significantly than in control animals. No significant differences were found in the content of cyclic guanosine monophosphate in control and adapted rats. Our results suggest that poor response of the myocardial cyclic nucleotide system to ischemia/reperfusion in adapted animals is associated with the antiarrhythmic and cardioprotective effect of adaptation. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 5, pp. 525–528, May, 2008     

Cyclic nucleotides in the rat caudate-putamen complex: histochemical characterization and effects of deafferentation and kainic acid infusion

Guanosine 3′,5′-cyclic monophosphate (cyclic guanosine monophosphate) and adenosine 3′,5′-cyclic monophosphate (cyclic adenosine monophosphate) were characterized immunohistochemically in the striatum of the rat. Cyclic guanosine monophosphate was associated primarily with fibrillar elements, some of which derived from cell bodies having maximum soma dimensions of 6–10 μm. Cyclic adenosine monophosphate was found primarily in relationship to oval or triangular somata 12–20 μm in maximum extent. Radio-frequency or suction ablations in brain regions—the ventral diencephalon, cortex and thalamus—providing or containing afferents to the caudate-putamen complex produced no effect on histochemical staining patterns or biochemically assessed levels of the two cyclic nucleotides. Loss of immunofluorescence to the two cyclic nucleotides was observed microscopically, however, following intrastriatal infusion of kainic acid; cyclic nucleotides in the non-injected striatum were unchanged. The latter histochemical results could not be corroborated biochemically. Radioimmunoassays showed no net effect of kainic acid on levels of the two cyclic nucleotides in the infused caudateputamen nucleus, whereas levels of these two chemical compounds were increased to 170–219% in the contralateral striatum.It was concluded that, as assessed histochemically, (1) cyclic guanosine monophosphate is primarily associated with glial cells and/or ‘glial-like’ neurons whereas cyclic adenosine monophosphate is found in relationship to neurons and (2) the striatal tissue elements containing these two cyclic nucleotides are organized primarily within the caudate-putamen complex. In addition, (3) immunohistochemical procedures for cyclic nucleotides may assay only tightly bound stores of cyclic nucleotides, whereas biochemical methods may measure both labile and stable pools. This last consideration permits reconciliation of differing results obtained with histochemical and biochemical techniques following intrastriatal infusion of kainic acid.     

Repeated antidepressant therapy increases cyclic GMP signaling in rat hippocampus

Cyclic adenosine monophosphpate (cAMP) signaling is thought to be involved in the pathophysiology of major depressive disorder and antidepressant action; however, relatively little is known about the possible role of cyclic guanosine monophosphate (cGMP) signaling. Accumulating evidence suggests that crosstalk occurs between cAMP and cGMP pathways. There is a need to clarify the trajectory of cAMP and cGMP concentrations, their synthesis by cyclases, and degradation by phosphodiesterases (PDEs) to understand the role of cyclic mononucleotide signaling in the effect of chronic antidepressant therapy. We used quantitative real-time PCR and enzyme immunoassay to systematically investigate the expression of intracellular signaling cascade elements in the hippocampus of rats chronically treated with the antidepressants fluoxetine and amitriptyline. We found increased cGMP levels, which were consistent with our findings of decreased PDE gene expression. Immunoassay results showed unchanged cAMP levels. We conclude that increased cGMP signaling might underlie the efficacy of chronic antidepressant treatment.     

Presence of atrial natriuretic factor and cyclic guanosine monophosphate in saliva. Comparison of plasma and salivary concentrations during a head-down tilt

Summary Using a specific and sensitive radio-immunoassay involving separation and extraction procedures, we measured the concentration of saliva and plasma atrial natriuric factor (ANF) and cyclic guanosine monophosphate (cGMP) in men before and during a 10h head-down tilt at -6°. Saliva values closely correlated with plasma for ANF (r=0.7-0.95) and for cGMP (r=0.65-1). During this dynamic test, the mean concentrations of ANF and cGMP were significantly higher after 15 and 45 min, respectively, this increase persisting for 3.5 h. We concluded that the concentration of ANF in saliva may be significantly affected by a marked fluid shift from the lower to the upper half of the body. This is the first time that the presence of ANF and cGMP has been demonstrated in saliva. The great advantage of studying saliva is that it can be obtained non-invasively in athletes or during space flight. This methodology will be used during the Soviet-French space flight (Antares Project) planned for 1992.     

Adrenaline stimulated cyclic adenosine monophosphate response in leucocytes is reduced after prolonged physical activity combined with sleep and energy deprivation

Summary The mechanism for adrenergic desensitisation during physical stress was studied by measuring [¹²⁵I] cyanopindolol ([¹²⁵I]CYP) binding sites and the adrenaline stimulated cyclic adenosine monophosphate (cAMP) responses in peripheral blood leucocytes from ten male cadets during a 5-day military training course. The cadets had physical activities around the clock corresponding to a daily energy consumption of about 40,000 kJ but with an intake of only 2,000 kJ, and only 1–3 h of sleep in the 5 days. During the course, the maximal cAMP response to adrenaline stimulation was reduced to about 45% in granulocytes and to 52% in mononuclear cells, and the half maximal response was obtained only at 5–10 times higher adrenaline concentrations than in the control experiment. The binding sites for [¹²⁵I]-CYP in mononuclear cells increased during the course. However, [¹²⁵I]-CYP measured not only surface receptors but also intracellular receptors and might even have represented other binding sites. In conclusion, this study showed that decreased cAMP response to adrenergic stimulation would seem to be one of the mechanisms behind adrenergic desensitisation during stress.     

Cytochemical localization of 5'-nucleotidase activity in retinal photoreceptor cells

Further cytochemical studies on the ultrastructural localization of 5'-nucleotidase in the rat retina have revealed activity to be associated with the complex synapses formed by the rod spherules of the receptors and the bipolar and horizontal cell processes. Activity was also seen on the axolemma of receptor fibers. In the rod inner segment strong reaction product is located intracellularly. In the rod outer segment the enzyme appears to be located only on the cytoplasmic side of the disc membrane and not intradiscally . Retinal pigment cells are rich in 5'-nucleotidase. Their microvilli accompany the tips of the receptor cells and show enzyme activity in an ecto position. A role for 5'-nucleotidase is possible in the metabolism of guanylate and adenylate nucleotides both of which are important for visual transduction processes.     

Excitatory amino acids in the chick retina: possible involvement of cyclic guanosine monophosphate

An investigation has been made of the ability of excitatory amino acids to alter the levels of chick retinal cyclic guanosine monophosphate (GMP). Kainic acid, N-methyl-D-aspartic acid and quisqualic acid each produced dose-related increases in cyclic GMP, and these could be attenuated by the addition of excitatory amino acid antagonists. It appears likely that in addition to its proposed role in visual transduction, this nucleotide may be involved in excitatory amino acid function in the chick retina.     

Catecholamines,lymphocyte subsets,and cyclic adenosine monophosphate production in mononuclear cells and CD4+ cells in response to submaximal resistance exercise

We examined the effect of 30 min of submaximal resistance exercise on free and sulphoconjugated plasma catecholamine concentrations determined by high performance (-pressure) liquid chromatography separation, the distribution of circulating lymphocytes quantified by flow cytometry, and isoproterenol induced cyclic adenosine monophosphate (cAMP) production in mononuclear cells (MNL) and CD4⁺ cells. Venous blood samples were taken before, immediately after and 45 min after exercise. Resistance exercise increased free plasma adrenaline (A) and noradrenaline (NA) concentrations, whereas sulphoconjugated catecholamine concentrations remained unchanged. Exercise induced leucocytosis and lymphocytosis was predominantly manifested by an increase in the number of total lymphocytes, monocytes, CD3⁺, CD8⁺ cells and CD3^– CD16/CD56^– cells. Redistribution resulted in a decrease in the CD4^–: CD8⁺ ratio. The total number and distribution of lymphocytes returned to baseline after 45-min rest. An exercise-induced increase in the number of CD3^– CD16/CD56⁺ cells was significantly correlated with the increase in plasma NA (r = 0.66;P = 0.035), indicating a NA dependent process of redistribution. The cAMP-production in MNL was significantly elevated after resistance exercise, when cells were stimulated with 1 mol·1^–1 isoproterenol [pre-exercise 16.5 (SD 3.3); postexercise 21.6 (SD 9.8); 45 min postexercise 10.7 (SD 2.8)]. The cAMP production in CD4⁺ cells was not affected by exercise. Therefore, it is discussed whether redistribution is responsible for the exercise induced increase in cAMP production in MNL.