白细胞介素-2对心肌β-肾上腺素受体作用的调制

目的：研究生理浓度白细胞介素-2（IL-2）对β-肾上腺素受体激动剂异丙肾上腺素（ISO）心肌细胞效应的调制作用及其信号途径。方法： 采用酶解分离的成鼠心室肌细胞模型，用视频跟踪系统测定单个心室肌细胞的收缩幅度、最大收缩速度和最大舒张速度（±dL/dtmax）；以Fura-2/AM为钙探针，用细胞内双波长钙荧光系统检测心肌［Ca2+］i的变化。结果： ① ISO显著增加心肌细胞的收缩幅度和±dL/dtmax，2×103 U/L的IL-2预处理15 min对心肌细胞的收缩没有影响，但是使心肌细胞对ISO的反应明显降低；② ISO浓度依赖性地增加心肌细胞的钙瞬态值，EC50为（0.12±0.01）μmol/L。2×103U/L的IL-2预处理15 min对心肌细胞的钙瞬态值没有影响，但是使心肌细胞对ISO的反应曲线显著降低，EC50为（0.44±0.06）μmol/L；③ 20 mg/L CTX预处理12 h可显著增加心肌细胞的钙瞬态值，2×103 U/L 的IL-2处理5 min可显著降低钙瞬态值；④ Forskolin显著增加单个心肌细胞的钙瞬态值，IL-2 2×103 U/L预处理15 min后，forskolin增加钙瞬态值的最大效应降低。结论： 生理浓度的IL-2 (2×103 U/L)能够显著抑制ISO对单个分离心肌细胞的正性肌力作用和钙瞬态值增高作用。IL-2的调制作用可能是通过抑制Gs蛋白，降低AC的活性来实现的。     

白细胞介素-2对大鼠心室肌细胞收缩功能的影响及其机制探讨

白细胞介素 2 (interleukin - 2 ,IL - 2 )是机体复杂免疫网络中起调节作用的重要细胞因子之一。越来越多的资料表明IL -2与心血管系统的生理活动和病理过程之间存在密切关系。但目前有关IL - 2对心脏的直接作用及其机理的研究尚不够深入。目的 :研究细胞因子白细胞介素 - 2对心肌细胞收缩功能的影响及其可能机制。方法 :采用酶解分离成年大鼠心室肌细胞模型 ,用视频跟踪计算机系统记录测定单个心室肌细胞收缩反应。心肌细胞收缩参数包括最大收缩幅度 (dL)、细胞最大收缩速度 (+dL/dtmax)、细胞最大舒张速度 (-dL/dtmax)、舒张末期细胞…     

白细胞介素-2及其受体与肿瘤基因治疗

作为最重要的细胞因子之一,白细胞介素-2(IL-2)抗瘤作用的研究一直引导着肿瘤生物免疫治疗的方向。本文从分子生物学和细胞生物学角度介绍IL-2的结构、激活信号系统、功能活性、各免疫细胞的IL-2分泌动力学特点;IL-2受体亚单位组成、表达调控、功能意义及在不同细胞中的表达状况;IL-2基因转导接种疗法的基本方法、作用原理、主要优点、近年获得的实验与临床研究数据、以及待解决的问题等。     

白细胞介素-2（IL-2）对中枢神经系统的影响

白细胞介素-2(IL-2)是T-淋巴细胞产生的一种细胞因子，它不仅影响着免疫系统，而且也调控着中枢神经系统的功能。本文根据前人的研究和自己的实验，综述了IL-2和IL-2受体(IL-2R)的一般特征、在中枢的定位和对中枢的影响及其可能的作用机理。     

白细胞介素-6与2型糖尿病发生的研究进展

白细胞介素 - 6 (IL - 6 )是一种多功能的细胞因子。 IL - 6的升高可通过激活急性相反应影响 2型糖尿病的发病 ,并可通过与胰岛素、瘦素的相互作用与 2型糖尿病的发生相关联     

白细胞介素-15及其受体

白细胞介素-15(IL-15)是一种新发现的细胞因子,其生物学性质与IL-2相似。IL-15的受体由IL-15Rα、IL-2Rβ、IL-2Rγ组成,其中IL-2Rγ是参与IL-15信号传递过程的必要成分。IL-15和IL-2的体内表达及受体分布存在差异预示着IL-15在体内具有独特的生物学作用。     

γ-干扰素抗体对早期流产大鼠γ-干扰素、白细胞介素-2、白细胞介素-4的表达及滋养层细胞凋亡的影响

目的:探讨γ-干扰素(IFN-γ)抗体对孕鼠早期流产的影响及其机制.方法:实验孕鼠随机分成流产模型组、IFN-γ抗体组、流产模型+ IFN-γ抗体组及正常对照组.酶联免疫吸附法测定各组大鼠血清IFN-γ、白细胞介素-2(IL-2)、白细胞介素4(IL-4)水平,免疫组织化学检测子宫蜕膜组织中Bcl-2和Bax蛋白的表达,Hoechst 33342荧光染色检测滋养层细胞凋亡情况.结果:血清测定数据显示,流产模型组IFN-γ、IL-2水平高于正常对照组,IL-4水平低于正常对照组;流产模型+IFN-γ抗体组IFN-γ、IL-2水平低于流产模型组,高于IFN-γ抗体组;IL-4水平高于流产模型组,低于IFN-γ抗体组.免疫组织化学Bcl-2和Bax蛋白阳性产物光密度值比值(Bax/Bcl-2)流产模型+IFN-γ抗体组低于流产模型组.结论:大鼠血清中3种细胞因子IFN-γ、IL-2、IL-4表达的改变及滋养层细胞凋亡可能是流产发生的重要因素.应用IFN-γ抗体可降低孕鼠IFN-γ、IL-2水平,升高IL-4水平,抑制滋养层细胞的凋亡,从而使流产率降低.     

白细胞介素—2与骨髓移植

ＩＬ－２与骨髓移植关系密切。ＩＬ－２激活的骨髓细胞为白血病患者的自体骨髓移植提供了一种净化骨髓的有效方法。在非自体骨髓移植后，应用ＩＬ－２能增强移植物的抗肿瘤活性，协助清除体内残留的肿瘤细胞以降低血液恶性肿瘤的复发率；且对ＧＶＨＤ具有抑制作用。本文对ＩＬ－２增强骨髓移植受体的抗肿瘤效果和抑制ＧＶＨＤ的机理进行了探讨。     

白细胞介素-20、白细胞介素-22研究进展

白细胞介素(IL)-20、IL-22属于IL-20亚家族细胞因子,IL-20亚家族细胞因子与IL-10一同属于IL-10家族.IL-20亚家族细胞因子在结构、功能、作用的受体复合物及靶细胞上具有相似性.与IL-10家族其它成员是抑炎性因子不同,IL-20是促炎性因子,且主要在炎症早期发挥作用.IL-22在不同疾病中表现出促炎或抑炎的不同作用,其在维持黏膜屏障功能及组织内稳态中发挥了重要作用.因而研究IL-20、IL-22的细胞来源、作用的靶细胞、表达调节以及作用机制可能会使IL-20和IL-22成为治疗疾病的靶点.     

瑞香素预处理对急性胰腺炎大鼠组织病理变化和白细胞介素-6、白细胞介素-10水平的作用

目的:观察瑞香素(Daphnetin,Da)对急性胰腺炎(Acute pancreatitis,AP)大鼠组织病理学和血清白细胞介素-6(IL-6)、白细胞介素-10(IL-10)水平的影响,探讨Da对AP的治疗价值和可能机制。方法:雄性Wistar大鼠32只,随机分为四组:假手术组(Sham组)、急性胰腺炎组(AP组)、Da预处理组(Da+AP组)、Da对照组(Da+Sham组),每组各8只。采用手术分离胰胆管并逆行注射5%牛磺胆酸钠溶液(1ml/kg)建立AP模型(AP组);Sham组不注射牛磺胆酸钠;Da+AP组和Da+Sham组于手术前30min腹腔注射Da(4mg/kg)后,Da+AP组同AP组处理,Da+Sham组同Sham组处理。术后12h开腹摘取胰腺头部,开胸心脏采血,分别观察胰腺组织病理学改变和血清IL-6、IL-10水平变化。结果:AP组胰腺组织病理学评分和血清IL-6水平明显高于Sham组(P0.05),IL-10水平明显低于Sham组(P0.05);与AP组比较,Da+AP组胰腺组织学评分和血清IL-6水平均降低(P0.05),血清IL-10水平明显升高(P0.05);Da+Sham组各指标水平与Sham组差异无统计学意义(P0.05)。结论:Da可能通过降低促炎因子IL-6和提高抗炎因子IL-10水平减轻胰腺急性炎性损伤,从而起到保护胰腺的作用。     

白细胞介素-2预处理对缺氧/复氧心肌细胞收缩功能的影响

目的：观察白细胞介素-2（IL-2）预处理对缺氧/复氧过程中心肌细胞收缩功能的作用并探讨其作用机制。方法： 采用酶解法分离成年大鼠心室肌细胞缺氧/复氧模型，用视频跟踪计算机系统记录测定单个心室肌细胞收缩。心室肌细胞收缩参数包括最大收缩幅度（dL）、细胞最大收缩速度（+dL/dtmax）、细胞最大舒张速度（-dL/dtmax）和舒张末期细胞长度。结果： ①缺氧/复氧过程中，缺氧5、10、15和20 min时，心肌细胞dL、+dL/dtmax和-dL/dtmax明显降低。复氧5 min 时±dL/dtmax和dL有所恢复，但复氧10 min后±dL/dtmax、dL和舒张末期细胞长度又明显降低。②2×103 U/L IL-2对心室肌细胞收缩无明显作用。用此浓度IL-2预处理心室肌细胞15 min可明显改善缺氧/复氧引起的心室肌细胞收缩功能的减弱。③用选择性κ-阿片受体拮抗剂nor-BNI（10-8 mol/L）预处理后，IL-2对缺氧/复氧过程中心室肌细胞收缩的影响被减弱。④PKC抑制剂chelerythrine(3×10-6 mol/L) 可明显减弱IL-2的作用。⑤IL-2对缺氧/复氧过程中心室肌细胞收缩的影响可被线粒体ATP敏感性钾通道阻断剂5-HD（10-4 mol/L)明显抑制。结论： 2×103 U/L IL-2预处理可明显改善缺氧/复氧心室肌细胞的收缩功能。其作用是由κ-阿片受体介导的，IL-2作用的信号转导途径涉及PKC和线粒体ATP敏感性钾通道。     

白细胞介素-2对缺氧/复氧心肌细胞[Ca2+]i的作用

目的:观察白细胞介素-2(IL-2)对心肌细胞在缺氧/复氧过程中电刺激诱导的[Ca²⁺]i的作用。方法:采用酶解分离成年大鼠心室肌细胞化学缺氧模型, 以Fura-2/AM为钙探针, 用细胞内双波长钙荧光系统检测心肌[Ca²⁺]i的变化。结果:①缺氧/复氧过程中, 缺氧5min时, 心肌[Ca²⁺]i幅度降低、舒张末期[Ca²⁺]i升高, [Ca²⁺]i达峰时间(TTP)延长, 恢复时间(RT)延长。复氧10min后, 心肌[Ca²⁺]i幅度、舒张末期[Ca²⁺]i、TTP及RT逐渐回复, 但不能完全恢复到对照水平;②在缺氧期间加入IL-2(2×10⁵U/L), 复氧期间[Ca²⁺]i各参数回复减慢;③用κ-阿片受体拮抗剂nor-BNI(10^-8mol/L)预处理后, 缺氧+IL-2对复氧时[Ca²⁺]i作用的影响被减弱, 而δ-阿片受体拮抗剂纳曲吲哚(10^-6mol/L)预处理则无此作用。结论:缺氧时同时存在IL-2, 可加剧复氧时心肌[Ca²⁺]i的变化, 其机制可能是IL-2通过心肌κ-阿片受体而发挥作用。     

丹参对抗缺氧/复氧引起的大鼠心室肌细胞收缩和细胞内钙的改变

目的:观察丹参在常氧和缺氧/复氧过程中对心肌细胞收缩和电刺激诱导的细胞内钙([Ca²⁺]_i)瞬态的影响。方法: 采用酶解分离成年大鼠心室肌细胞化学缺氧模型, 用视频跟踪计算机系统和细胞内双波长钙荧光系统分别观察心肌细胞收缩力学和[Ca²⁺]_i等指标。结果:丹参(1-9 g/L)处理后降低心肌细胞最大收缩和舒张速率、收缩幅度以及电刺激诱导的[Ca²⁺]_i幅度, 且呈剂量依赖性。缺氧后, 与对照相比细胞收缩力和钙瞬态幅度降低、舒张末细胞长度缩短、舒张末钙水平增高;复氧后细胞收缩力、钙瞬态幅度和舒张末钙水平有所回复, 但不能达对照水平。用3 g/L的丹参处理后, 缺氧/复氧引起的心肌细胞最大收缩和舒张速率、收缩幅度和电刺激诱导的[Ca^2＋]_i幅度高于单纯缺氧组, 舒张末[Ca²⁺]_i水平低于单纯缺氧组。结论:丹参可对抗缺氧/复氧引起的大鼠心室肌细胞收缩力降低和细胞内动态和静态钙的变化。     

Regulation of calcium release by calcium inside the sarcoplasmic reticulum in ventricular myocytes

 To study the effects of changes in sarcoplasmic reticulum (SR) intraluminal Ca²⁺ on the Ca²⁺ release mechanism, we correlated the activity of single cardiac ryanodine receptor (RyR) channels, monitored in planar bilayers, with the properties of spontaneous elementary Ca²⁺ release events (sparks) in intact ventricular myocytes, monitored by scanning confocal microfluorimetry. Under both normal conditions and Ca²⁺ overload, induced by elevation of extracellular [Ca²⁺], Ca²⁺ sparks represented single populations of events. During Ca²⁺ overload, the frequency of sparks increased from 0.8 to 3.1 events per second per 100 μm line scanned, and their amplitude increased from 100 nM to 400 nM. The duration of the Ca²⁺ sparks, however, was not altered. Changes in the properties of Ca²⁺ sparks were accompanied by only an ≈ 30% increase in the SR Ca²⁺ content, as determined by emptying the intracellular Ca²⁺ stores using caffeine. When single Ca²⁺ release channels were incorporated into lipid bilayers and activated by cytoplasmic Ca²⁺ (≈ 100 nM) and ATP (3 mM), elevation of Ca²⁺ on the luminal side from 20 μM to 0.2–20 mM resulted in a 1.2-fold to 7-fold increase, respectively, in open probability (P _o). This potentiation of P _o was due to an increase in mean open time and frequency of events. The relative effect of luminal Ca²⁺ was greater at low levels of cytoplasmic [Ca²⁺] than at high levels of cytoplasmic [Ca²⁺], and no effect of luminal Ca²⁺ was observed to occur in channels activated by 0.5–50 μM cytoplasmic Ca²⁺ in the absence of ATP. Our results suggest that SR Ca²⁺ release channels are modulated by SR intraluminal Ca²⁺. These alterations in properties of release channels may account for, or contribute to, the mechanism of spontaneous Ca²⁺ release in cardiac myocytes Received: 15 May 1996 / Received after revision: 5 June 1996 / Accepted: 8 July 1996     

A method for recording intracellular [Ca2+] transients in cardiac myocytes using calcium green-2

Calcium green-2 (Ca green) is a non-ratio-metric fluorescent Ca²⁺ indicator with an affinity for Ca²⁺ (dissociation constant K_d=3 M) that is lower than more commonly used indicators such as fura-2 and fluo-3. This low Ca²⁺ affinity, coupled with a high quantum yield, allows cells to be loaded with low concentrations of Ca green, avoiding problems of cytosolic Ca²⁺ buffering and a low signal-to-noise ratio. This communication presents a method for monitoring intracellular [Ca²⁺] changes in isolated rat ventricular myocytes loaded with Ca green and the fluorescent pH indicator carboxy SNARF-1 (SNARF). SNARF provides a Ca²⁺-insensitive signal with which Ca green fluorescence can be corrected for cell motion and dye-loading artifacts.     

大鼠心肌细胞胞浆和核Ca2+震荡现象及其机制探讨

目的:在培养的新生大鼠心肌细胞上,观察多种刺激因素对细胞胞浆Ca²⁺([Ca²⁺]c)和核Ca²⁺([Ca²⁺]n)的影响,探讨其时间和空间关系及其机制。方法:以Fluo-4/AM荧光指示剂负载培养的心肌细胞,应用激光共聚焦扫描显微镜检测胞浆和核Ca²⁺震荡的变化。结果:正常心肌细胞内核Ca²⁺的荧光强度高于核周与细胞浆,三者均存在小幅度的钙震荡,分别加入去甲肾上腺素(10^-5mol/L)、异丙肾上腺素(10^-4mol/L)和三磷酸腺苷(ATP3×10^-3mol/L),均使心肌细胞钙震荡幅度明显升高(P＜0.01),L-型Ca²⁺通道阻滞剂维拉帕米(verapamil5×10^-4mol/L)、Ca²⁺-ATPase抑制剂thapsigargin(10^-6mol/L)和KCl(20mmol/L)使钙的周期性震荡消失。用thapsigargin10^-6mol/L预先阻断心肌细胞钙库的Ca²⁺摄取,去甲肾上腺素(10^-5mol/L)则不能引起钙震荡和荧光强度增加。结论:心肌细胞胞浆和核Ca²⁺均能产生钙震荡,而钙震荡的维持则依赖于细胞外Ca²⁺的内流、胞内钙库的Ca²⁺摄取和释放以及正常膜电位的维持。核与胞浆Ca²⁺变化不一致,提示细胞核上可能存在相对独立的Ca²⁺调节系统。     

Estimation of myofibrillar responsiveness to Ca2+ in isolated rat ventricular myocytes

 To estimate myofibrillar responsiveness to Ca²⁺, we used the relation between cell length and intracellular [Ca²⁺] ([Ca²⁺]_i) during tetanic contractions of isolated ventricular myocytes. Enzymatically isolated rat ventricular myocytes were loaded with fura-2 AM (4 μM for 10 min) and excited alternately at 340 nm and 380 nm. The ratio (R) of fura-2 fluorescence at these wavelengths [F(340)/F(380), an index of [Ca²⁺]_i] and cell length (L) were measured simultaneously. Following treatment with thapsigargin (0.2 μM), myocytes were stimulated at 10 Hz for 10 s to produce a tetanic contraction every min and an instantaneous plot of R vs L (R-L trajectory) was constructed. The R-L trajectory followed the same path during cell shortening and re-lengthening, suggesting that dynamic equilibrium between R and L was achieved during tetanus. Increasing the extracellular [Ca²⁺] from 1 to 8 mM extended the R-L trajectory without a substantial shift of the relation. The Ca²⁺-sensitizing thiadiazinone derivative, EMD57033 (1 μM), shifted the R-L trajectory to the left (sensitization of the myofibrils to Ca²⁺), whereas the non-selective phosphodiesterase inhibitor, 3-isobutyl-1-methylxantine (200 μM), shifted the R-L trajectory to the right (desensitization of the myofibrils to Ca²⁺), in agreement with previous results obtained using skinned preparations. We conclude that the R-L trajectory is useful for estimating the myofibrillar responsiveness to Ca²⁺ in isolated myocytes and may be beneficial for the evaluation of inotropic agents. Received: 13 March 1998 / Received after revision: 4 May 1998 / Accepted: 2 June 1998     

Decrease in sodium–calcium exchange and calcium currents in diabetic rat ventricular myocytes

This study was designed in order to gain insight into possible changes in the inward sodium–calcium exchange current (I_Na–Ca) and the L -type calcium current (I_Ca), in ventricular myocytes isolated from streptozotocin-induced diabetic rats. Recordings were made using the nystatin-perforated patch technique which minimizes interference with the normal intracellular Ca²⁺ buffering mechanisms. The averaged I_Na–Ca current density elicited by Ca²⁺ current was smaller in diabetic than in normal myocytes at all potentials tested. I_Na–Ca activated by rapid application of caffeine was significantly reduced and the decay phase was prolonged. The density of I_Ca was also significantly reduced by diabetes in the range of test potentials between –10 and +50 mV. In addition, the fast time constant of I_Ca inactivation, which represents mainly the sarcoplasmic reticulum (SR) Ca²⁺ release-induced inactivation, was significantly higher in diabetic than in normal myocytes. The decrease in I_Ca, which is the main source of trigger Ca²⁺ for SR Ca²⁺ release, may explain the significantly lowered peak systolic [Ca²⁺]_i previously shown in diabetic myocytes. As activation of I_Ca is essential for subsequent stimulation of I_Na–Ca, reduced I_Ca may contribute to decreasing activation of the Na⁺–Ca²⁺ exchanger.     

Effects of cytosolic Ca2+ on the Ca2+ content of the sarcoplasmic reticulum in saponin-permeabilized rat ventricular trabeculae

 Rat ventricular trabeculae were mounted for isometric tension recording, and then permeabilized with saponin. The Ca²⁺ concentration ([Ca²⁺]) within the permeabilized preparation (cytosolic [Ca²⁺]) was monitored continuously using Indo-1 and the integrals of Ca²⁺ transients resulting from brief caffeine application used as an index of the sarcoplasmic reticulum (SR) Ca²⁺ content. The relationship between SR Ca²⁺ content and cytosolic [Ca²⁺] was studied within the reported physiological range (i.e. 50–250 nmol · l^–1 Ca²⁺). Increasing cytosolic [Ca²⁺] from 50 nmol · l^–1 to 250 nmol · l^–1 increased the steady-state SR Ca²⁺ content about threefold. However, increasing [Ca²⁺] above 250 nmol · l^–1 typically resulted in spontaneous SR Ca²⁺ release, with no further increase in SR Ca²⁺ content. The SR Ca²⁺ content increased only slowly when cytosolic [Ca²⁺] was increased; it was unchanged 20 s after a rapid increase in cytosolic [Ca²⁺], but increased progressively to a new steady-state level during the following 1–2 min. In a parallel series of experiments using intact papillary muscles, increasing extracellular [Ca²⁺] (from 0.5 to 5 mmol · l^–1) significantly increased twitch tension within 20 s of the solution change. These results support previous suggestions that the SR Ca²⁺ content may increase when diastolic cytosolic [Ca²⁺] rises during inotropic interventions such as increased stimulus rate or extracellular [Ca²⁺]. However, the rate at which SR Ca²⁺ responds to changes in cytoplasmic [Ca²⁺] within the diastolic range does not appear rapid enough to explain the early potentiation of twitch tension in intact preparations after an increase in extracellular [Ca²⁺]. Received: 26 August 1997 / Accepted: 28 October 1997     

低氧后心肌钙瞬变变化与β-肾上腺素受体脱敏的关系

目的:慢性低氧时,心脏对β-肾上腺素受体激动的反应出现脱敏现象,细胞内钙[Ca²⁺]_i瞬变的幅度降低、时程延长,本研究观察上述变化在低氧时发生和发展的时间过程和对应关系。方法:在年龄对等的正常及慢性低氧1d、3d、1周、2周、3周、4周和8周的大鼠,分别分离正常及慢性低氧条件下的心室肌细胞,以Fura-2为[Ca²⁺]_i的指示剂,用光谱荧光法测定心肌细胞的[Ca²⁺]_i瞬变及其对心肌β-受体激动后反应的变化。结果:在低氧1d、3d、1周等时间内,电刺激引起的[Ca²⁺]_i瞬变、咖啡因引起的[Ca²⁺]_i瞬变及电刺激引起的[Ca²⁺]_i瞬变对β-受体激动剂异丙肾上腺素的增加反应无明显变化;在低氧2周以上时,电刺激引起的[Ca²⁺]_i瞬变的幅度开始降低,而时程开始延长,其对异丙肾上腺素的反应也开始降低。咖啡因引起的[Ca²⁺]_i瞬变幅度也开始降低;在低氧3周和4周时,上述变化程度逐渐加重;在低氧8周时各参数的变化有所恢复,但与4周时的变化程度无明显差异。结论:低氧2-4周时,心脏的β-肾上腺素受体发生脱敏现象,脱敏的机制与3种调节[Ca²⁺]_i瞬变的蛋白质:L-型钙通道、ryanodine受体操纵的钙通道和钙泵等活性的降低有关,后者也可能是低氧时心脏功能降低的重要机制。低氧4-8周时,心脏对低氧产生了适应和代偿。