右旋美托咪定后处理对大鼠心肌缺血再灌注损伤的保护作用

目的：评价右旋美托咪定（DEX）后处理对大鼠心肌缺血再灌注时Na⁺-K⁺-ATP酶和Ca²⁺-ATP酶活性的影响。方法：36个成年雄性Wistar大鼠心脏置于改良的Langendoff装置上,均为平衡灌注末HR>180次/min、左室收缩压>75mm Hg、室性早搏<2个/min的心脏模型,采用随机数字表法分为3组：对照组（A组）、缺血再灌注组（B组）、DEX处理组（C组）,每组12个。A组持续灌注KH液180 min,B组和C组在KH平衡灌注20 min时常温停灌40 min后恢复灌注,于再灌注即刻分别灌注KH液、含100 nmol·L^-1 DEX的KH液20 min,然后继续再灌注KH液100 min。监测心率（HR）、冠状动脉流出量（CF）,左心室发展压（LVDP）、左心室内压最大上升和下降速率（±dP/dt_max）,采用酶联免疫法测定心肌Na⁺-K⁺-ATP酶、Ca²⁺-ATP酶,以梗死心肌质量占心室质量的百分比表示心肌梗死率。结果：再灌注后A组心功能优于B组、C组（P<0.05）,C组优于B组（P<0.05）。与A组比较,B组和C组心肌梗死率较大,心肌组织Na⁺-K⁺-ATP酶、Ca²⁺-ATP酶的活性降低（P<0.05）;与B组比较,C组心肌梗死率低,心肌组织Na⁺-K⁺-ATP酶、Ca²⁺-ATP酶的活性较高（P<0.05）。结论：DEX后处理可提高Na⁺-K⁺-ATP酶和Ca²⁺-ATP酶的活性,减轻大鼠心肌缺血再灌注损伤。     

玉郎伞水提物对心肌缺血再灌注损伤心肌组织ATP酶和凋亡蛋白的影响

目的:研究玉郎伞水提物(WYLS)对大鼠离体心脏缺血再灌注(I/R)损伤心肌组织Na⁺-K⁺-ATP酶、Ca²⁺-ATP酶和凋亡蛋白的影响。方法:采用Langendorff离体心脏灌流法,停灌30 min再灌30 min建立大鼠心肌缺血再灌注损伤模型。观察WYLS对心肌组织Na⁺-K⁺-ATP酶、Ca²⁺-ATP酶活性的影响、心肌组织病理学变化、凋亡相关蛋白Bcl-2和Bax表达的影响。结果:与I/R组比较,WYLS高剂量组Na⁺-K⁺-ATP酶、Ca²⁺-ATP酶的活性明显增加(P<0.05或P<0.01),心肌受损程度明显减轻(P<0.05)。同时,WYLS高剂量组心肌Bax蛋白表达明显降低(P<0.01),Bcl-2蛋白表达无明显影响(P>0.05),但Bcl-2/Bax的比率明显增加(P<0.05)。结论:WYLS能减轻大鼠心肌I/R损伤,作用机制可能与减轻钙超载、抑制某些凋亡相关蛋白表达有关。     

白藜芦醇对心肌缺血再灌注过程中线粒体的保护

目的:探讨白藜芦醇对心肌缺血再灌注损伤过程中Ca²⁺-ATPase及HSP70表达的影响。方法:健康雄性SD大鼠40只,采用随机数字量表法分为4组(假手术组、缺血再灌注组、缺血预适应组、白藜芦醇组),采用结扎冠状动脉前降支制备心肌缺血再灌注损伤模型,于结扎前15 min及再灌注前1 min经舌下静脉注射白藜芦醇10 mg·kg^-1。提取心肌线粒体,紫外可见光分光光度计测定线粒体中SDH、Na⁺-K⁺-ATPase、Ca²⁺-ATPase活性;荧光分光光度计测定线粒体中游离钙、mPTP开放度及跨膜电位;RT-PCR及Western blot检测心肌组织HSP70、Ca²⁺-ATPase mRNA及蛋白质的表达。结果:白藜芦醇与缺血再灌注组及缺血预适应组相比,线粒体中SDH、Na⁺-K⁺-ATPase、Ca²⁺-ATPase的活性明显提高(P<0.05或P<0.01);线粒体内钙离子浓度明显下降(P<0.05或P<0.01)、mPTP开放程度减小(P<0.01)、线粒体膜电位增高(P<0.01);Ca²⁺-ATPase、HSP70在 mRNA或蛋白水平上的表达均有所增加(P<0.05或P<0.01)。结论:白藜芦醇可能通过增加心肌组织中Ca²⁺-ATPase、HSP70 mRNA和蛋白的表达,提高线粒体Ca²⁺-ATPase的活性,产生对大鼠心肌缺血再灌注损伤时线粒体的保护作用。     

Irisin通过Sirt1/UCP2拮抗二氯化钴诱导的心肌损伤作用

目的 探讨肌肉因子Irisin调节胞内保护蛋白Sirt1和线粒体解偶联蛋白2(uncoupling protein 2,UCP2)在心肌缺氧过程中发挥的作用及具体机制。方法 以CoCl₂作用H9c2心肌细胞24 h,构建心肌细胞体外缺氧模型。实验分为6组：control组、Irisin 10 nmol·L^-1组、Irisin 20 nmol·L^-1组、CoCl₂模型组、CoCl₂+Irisin 10 nmol·L^-1治疗组、CoCl₂+Irisin 20 nmol·L^-1治疗组。CCK-8法检测细胞存活率，Flow cytometry测定细胞凋亡和线粒体膜电位，探针法指示细胞内活性氧(reactive oxygen species, ROS)高低水平，Western blot法检测细胞内Sirt1、UCP2、Bcl-2、Bax、cleaved-caspase3的表达水平。结果 心肌细胞H9c2缺氧模型组细胞活力下...     

淫羊藿苷对高糖诱导H9c2心肌细胞凋亡的抑制作用

目的 研究淫羊藿苷(ICA)对高糖诱导大鼠心肌细胞H9c2凋亡的抑制作用及其机制。方法 H9c2细胞分为细胞对照组、高糖模型组、高糖+ICA 2.5,5.0,10.0,20.0和40.0μmol·L^-1组，ICA培养1 h后更换含葡萄糖33 mmol·L^-1的培养基培养3 d。CCK-8法检测H9c2细胞存活率，Annexin V-FITC/PI双染色流式细胞术检测细胞凋亡率，生物化学法测定细胞培养基葡萄糖消耗量和乳酸水平，DCFH-DA荧光探针法测定细胞内活性氧(ROS)含量，Mito-Tracker Red CMXRos荧光探针法测定线粒体膜电位，Western印迹法检测动力素相关蛋白1(DRP1)、线粒体分裂蛋白1(FIS1)、线粒体融合蛋白2(MFN2)、视神经萎缩症蛋白1(OPA1)和活化胱天蛋白酶3/6/7蛋白表达水平。结果 与细胞对照组比较，高糖模型组H9c2细胞存活率、线粒体膜电位、MFN2和OPA1蛋白表达水平显著降低(P<0.01)，细胞凋亡率、培养基葡萄糖消耗量和乳酸水平及细胞内ROS含量、DRP1、FIS1和活化...     

前胡香豆素对肾型高血压大鼠左室肥厚及心肌胞内钙、Na+,K+-ATP酶和Ca2+,Mg2+-ATP酶活性的影响

目的研究前胡香豆素组分对肾型高血压左室肥厚的预防和逆转作用及机制。方法用两肾一夹肾型高血压左室肥厚大鼠(RHR)模型,测定前胡香豆素组分对其血压、左室湿重、心肌细胞面积、胞内静息钙及胞膜和线粒体ATP酶活性的影响。结果前胡香豆素组分(30 mg·kg^-1·d^-1,ig)预防组及逆转组大鼠血压、左室湿重/体重均较肥厚组明显降低;左室心肌细胞面积、胞内静息钙均较肥厚组降低;对KCl致钙浓度升高亦明显低于肥厚组;两组均可增加心肌细胞膜及线粒体Na⁺,K⁺-ATP酶和Ca²⁺,Mg²⁺-ATP酶活性。结论前胡香豆素组分可预防及逆转RHR左室肥厚,减少心肌细胞内钙含量,增加ATP酶活性。     

nNOS抑制剂亚胺基烯丁基-L-鸟氨酸对心肌缺血再灌注损伤的影响及机制

目的 探讨nNOS选择性抑制剂亚胺基烯丁基-L-鸟氨酸(L-VNIO)对心肌缺血再灌注(I/R)损伤的影响及机制。方法 构建SD大鼠离体心脏I/R模型和H9c2细胞缺氧/复氧(H/R)模型;nNOS抑制剂L-VNIO(10μmol·L-1)持续给药整个再灌注或复氧过程。TTC染色测定心肌梗死面积;流式细胞术检测H9c2细胞凋亡率;Fluo-3/AM Ca²⁺荧光探针通过流式细胞仪检测H9c2细胞内Ca²⁺浓度;试剂盒法测定离体心脏灌流液乳酸脱氢酶(LDH)、丙二醛(MDA)水平以及H9c2细胞MDA水平和超氧化物歧化酶(SOD)活性;离体心脏提取肌浆网,试剂盒法检测肌浆网Ca²⁺-ATP酶(SERCA)活性,Western blotting检测肌浆网SERCA蛋白表达;Western blotting检测离体心脏中受磷蛋白(PLB)和兰尼碱受体2(RyR2)蛋白表达水平和磷酸化水平。结果 与I/R或H/R模型组相比,L-VNIO显著降低细胞凋亡率,减少心肌梗死面积,降低LDH、MDA水平,提高SOD活性,差异均有统计学意...     

高脂通过线粒体通路诱导H9c2心肌细胞损伤

目的探讨高脂通过线粒体凋亡通路对H9c2心肌细胞的损伤作用。方法棕榈酸(0～0.4 mmol·L~(-1))刺激H9c2心肌细胞24 h和0.2 mmol·L~(-1)棕榈酸刺激H9c2心肌细胞(0～48 h);MTT法评估细胞生长状态;活性氧试剂盒检测细胞内活性氧水平;凋亡试剂盒检测细胞凋亡情况;线粒体膜电位试剂盒检测线粒体膜电位变化;免疫印迹法检测细胞内线粒体凋亡相关蛋白Cyt-C、Cleaved casepase-3、Bax、Bcl-2表达水平。结果棕榈酸刺激H9c2心肌细胞24 h,棕榈酸0.2、0.4 mmol·L~(-1)组细胞增殖率均出现明显下降;细胞内活性氧水平逐渐升高,线粒体膜电位下降,细胞凋亡增加。棕榈酸(0.2 mmol·L~(-1))刺激H9c2心肌细胞24、36、48 h均引起细胞增殖率明显下降。棕榈酸(0.4 mmol·L~(-1))刺激H9c2心肌24 h,线粒体相关蛋白Cyt-C、Cleaved casepase-3、Bax表达均明显增高(P <0. 05),而Bcl-2明显降低(P <0. 05)。结论线粒体凋亡信号通路可能对高脂所致H9c2心肌细胞损伤起重要作用。     

参麦注射液静注对红细胞膜Na+-K+-ATP酶的影响

为了解参脉注射液对患者红细胞(RBC)膜Na+-K+-ATP酶的影响,本研究随机选择级择期上腹部手术男性患者60例,根据参脉给药剂量的不同,随机分为三组,每组20例Ⅰ组、Ⅱ组和Ⅲ组剂量分别为40,60,80 mg/kg.给药后10,20,30min时测定各组患者静脉血红细胞膜Na+-K+-ATP酶活性,各组患者血压、心率、氧饱和度的变化也同时被记录.结果发现参脉注射液对RBC膜Na+-K+-ATP酶活性具有短暂的抑制作用,当参脉注射液输液量为80 mg/kg时对心率也存在短暂的减慢作用.     

PKC/HSP70通路介导白藜芦醇对心肌细胞缺氧/复氧损伤的保护作用

目的：探讨白藜芦醇（resveratrol,RSVL）对心肌细胞缺氧/复氧损伤（anoxia/reoxygenation injury,ARI）的保护作用及机制。方法：分离、纯化SD乳鼠原代心肌细胞,建立缺氧/复氧损伤模型,采用随机数字量表法分为6组：正常对照（CON）组、ARI组、ARI+不同浓度RSVL（25,50,75 μmol·L^-1）预处理组、ARI+RSVL（75 μmol·L^-1）+PKC抑制剂白屈菜红碱（1 μmol·L^-1）组。倒置相差显微镜观察心肌细胞生长形态,自发搏动频率和节律;Hoechst 33258染色计算细胞凋亡率;比色法测定细胞培养液中LDH、CK漏出量及细胞内Ca²⁺-ATPase活性;荧光分光光度计测定细胞内游离钙离子浓度;Western blot检测心肌细胞PKC、HSP70及Ca²⁺-ATPase蛋白水平。结果：不同浓度RSVL与ARI组相比,心肌细胞折光性好,搏动有力而规则,频率在90~115次/分（P<0.01）;呈剂量依赖性减少细胞凋亡（P<0.01）,降低培养液中LDH和CK漏出量（P<0.05或P<0.01）,提高心肌细胞Ca²⁺-ATPase活性及降低细胞内[Ca²⁺]_i量（P<0.05或P<0.01）;心肌细胞PKC、HSP70及Ca²⁺-ATPase蛋白表达增加（P<0.05或P<0.01）。而RSVL的保护作用可被PKC抑制剂白屈菜红碱所取消（P<0.05或P<0.01）。结论： RSVL可能通过PKC/HSP70通路产生对心肌细胞缺氧/复氧损伤的保护作用。     

Binding domain of oligomycin on Na(+),K(+)-ATPase

Oligomycin inhibits Na⁺,K⁺-ATPase activity by stabilizing the Na⁺ occlusion but not the K⁺ occlusion. To locate the binding domain of oligomycin on Na⁺,K⁺-ATPase, the tryptic-digestion profile of Na⁺,K⁺-ATPase was compared with the profile of Na⁺ occlusion within the digested Na⁺,K⁺-ATPase in the presence of oligomycin. The Na⁺ occlusion profile is responsible for the digestion profile of the -subunit, which is the catalytic subunit of the ATPase. The effect of oligomycin on chimeric Ca²⁺-ATPase activity was examined. The chimera used, in which the 163 N-terminal amino acids of chicken sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase 1 were replaced with the 200 N-terminal amino acids of the chicken Na⁺,K⁺-ATPase 1-subunit, partially retains the Na⁺-dependent characteristics of Na⁺,K⁺-ATPase, because the chimeric Ca²⁺-ATPase activity is activated by Na⁺ but inhibited by ouabain, a specific inhibitor of Na⁺,K⁺-ATPase (Ishii, T., Lemas, M.V., Takeyasu, K., 1994, Proc. Natl. Acad. Sci. U. S. A., 91, 6103–6107). Oligomycin depressed the activation by Na⁺ of the chimeric Ca²⁺-ATPase activity. These findings suggest that the 200 N-terminal amino acids of the Na⁺,K⁺-ATPase -subunit include a binding domain for oligomycin.     

Inhibition of P-type ATPases by [(dihydroindenyl)oxy]acetic acid (DIOA), a K+ -Cl- cotransporter inhibitor

[(Dihydroindenyl)oxy]acetic acid (DIOA) has been used as a potent inhibitor of K⁺–Cl⁻ cotransporter (IC₅₀ = 10 μM). Here we found that DIOA inhibited activities of P-type ATPases such as dog kidney Na⁺,K⁺-ATPase (IC₅₀ = 53 μM), hog gastric H⁺,K⁺-ATPase (IC₅₀ = 97 μM) and rabbit muscle Ca²⁺-ATPase (IC₅₀ = 127 μM). In the membrane preparation of the LLC-PK1 cells stably expressing rabbit gastric H⁺,K⁺-ATPase, DIOA inhibited activities of the endogenous Na⁺,K⁺-ATPase (IC₅₀ = 95 μM) and the exogenous H⁺,K⁺-ATPase (IC₅₀ = 75 μM). 5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), a Cl⁻ channel blocker, had no effects on the DIOA-elicited inhibition of the P-type ATPases. These findings suggest that lower concentration of DIOA (< 20–30 μM) should be used for evaluation of the activity of K⁺–Cl⁻ cotransporter without affecting the activities of coexisting Na⁺,K⁺-ATPase and/or H⁺,K⁺-ATPase in cells.     

The effect of the myotoxic Lys49 phospholipase A2 from Agkistrodon contortrix laticinctus snake venom on Na/K-ATPase activity of toad bladders

ACLMT is a myotoxic Lys49 phospholipase A₂ isolated from the venom of the snakeAgkistrodon contortrix laticinctus. We have previously shown that ACLMT increases baseline water transport and partially inhibits vasopressin-stimulated water transport across toad bladders due to an increase in cytosolic calcium. However, these evidences provide insufficient insight into the mechanisms involved in the effects of ACLMT on membrane permeability. In an attempt to better understand such mechanisms, the current study aimed to investigate whether the Na⁺/K⁺-ATPase activity of isolated toad bladders can be affected by the ACLMT and the synthetic peptide from its C-terminal region. The toxin significantly decreased the Na⁺/K⁺-ATPase, while the peptide did not alter it. These findings suggest that the effects of ACLMT on membrane permeability may be due to the inhibition of the Na⁺/K⁺-ATPase activity, and that the C-terminal region may not play a relevant role in this effect. This study contributes toward a better understanding of the mechanisms involved in the toxicity of the snake venom Lys49 PLA₂ myotoxins on biological tissues.     

Physical-chemical-activity relationship of organic solvents: Effects on Na-K-ATPase activity and membrane fluidity in mouse synaptosomes

Physical-chemical-activity relationship of aromatic hydrocarbons (n = 10) and alkyl acetates (n = 16) with respect to their in vitro effects on synaptosomal membranes was studied. Na⁺-K⁺-adenosine triphosphatase (Na⁺-K⁺-ATPase) activity and membrane fluidity, which was determined using the fluorescence probe 1,6-diphenyl-1,3,5-hexatriene, were used as potential indicators of neuronal cell toxicity. The potency of inhibition for the enzyme (IC₅₀), the potency of increasing membrane fluidity (IC_12.5), and n-octanol/water partition coefficient (P) were all determined experimentally for 26 solvents. Correlation analyses were made on aromatic hydrocarbons and on alkyl acetates. There were linear relationships between log P and pIC₅₀ (log1/IC₅₀) values, and between log P and pIC_12.5 (logl/IC_12.5) values, indicating that the hydrophobicity of the solvents determines their toxic ability to affect membrane environment; the more hydrophobic the solvents are, the more toxic they are. A direct linear relationship between Na⁺-K⁺-ATPase activity pIC₅₀ and membrane fluidity pIC_12.5 values was also shown. This predictive correlation suggests a similar mechanism of membrane surface interaction govering both processes that are common to the test solvents. The present results confirm the importance of the lipid environment of neuronal membranes in maintaining the normal function of membrane-bound protein.     

The toxicity of H2O2 on the ionic homeostasis of airway epithelial cells in vitro.

Oxygen species may be formed in the air spaces of the respiratory tract in response to environmental pollution such as particulate matter. The mechanisms and target molecules of these oxidants are still mainly unknown but may involve modifications of the ionic homeostasis in epithelial cells. Cytosolic concentrations of Ca²⁺ (Fura2) and Na⁺ (SBFI) and short-circuit current (Isc) were followed in primary cultures of human nasal epithelial cells and in the cell line 16HBE14o⁻ after exposure to H₂O₂ or ·OH (H₂O₂+Fe²⁺). Cells were grown on glass coverslips for ionic imaging or on permeable snapwell inserts for Isc studies. Exposure of the apical as well as the basal side of the cultures to H₂O₂ or ·OH induced a concentration-dependent transient increase in Isc which is due to a transient secretion of Cl⁻. Ca_i also increased transiently with approximately the same kinetics. The response was dependent on the release of calcium from intracellular stores. Na_i on the contrary increased steadily over more than an hour. When the apical membrane was permeabilized with gramicidin, ·OH inhibited the Na⁺ current (a measure of Na⁺-K⁺-ATPase activity in the baso-lateral membrane). The arrest of the pump was significant after 30 min exposure to oxidant. On the other hand no increase in the apical or baso-lateral sodium conductances could be detected. The progressive arrest of the Na⁺/K⁺-pump may contribute to the sustained elevation of Na_i. This strong modification in the cellular ionic homeostasis may participate in the stress response of the respiratory epithelium through alterations in signal transduction pathways.     

人参皂苷三醇型与二醇型在不同量比下对大鼠机体燥性的影响研究

目的 探究人参皂苷三醇型与人参皂苷二醇型含量比值变化对大鼠机体的燥性影响.方法 将30只SD大鼠随机分为空白组和4个实验组(R值=0.5、1、1.5、2),每组6只.采用Elisa法测定大鼠血中Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶、乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)以及脑中胆碱酯酶(ChE)、...