D-氨基葡萄糖盐酸盐激活Ca2+信号通路诱导淋巴细胞增殖

目的研究D-氨基葡萄糖盐酸盐(GAH)诱导小鼠脾淋巴细胞增殖及其机制。方法采用MTT法、荧光探针标记法、免疫荧光法观察GAH对淋巴细胞增殖、淋巴细胞内的钙离子浓度、调神经磷酸酶表达的影响。结果GAH能够诱导小鼠淋巴细胞增殖,提高淋巴细胞内钙离子浓度,增强钙调神经磷酸酶的表达。结论GAH通过提高淋巴细胞内钙离子浓度,增加钙调神经磷酸酶的表达,激活淋巴细胞的Ca2 信号通路,诱导淋巴细胞增殖。     

从Ca2+通路研究紫草多糖促进小鼠淋巴细胞增殖的机制

目的 探讨ZCP对淋巴细胞增殖和Ca2+浓度的影响.方法 MTT比色法检测其对淋巴细胞增殖;激光共聚焦显微镜观察细胞内的Ca2+浓度.结果 ZCP能促淋巴细胞增殖,提高细胞内Ca2+浓度.结论 ZCP可通过增加淋巴细胞内Ca2+浓度从而使淋巴细胞活化和增殖.     

N-乙酰氨基葡萄糖激活Ca2＋信号通路体外诱导小鼠T淋巴细胞增殖

目的N-乙酰氨基葡萄糖（N—acetyl—D—glucosamine，NAc—Glu）是甲壳素的-种重要衍生物。其分子量小，水溶性好，有更独特的生理生化活性，近些年已经引起越来越多的关注。但关于NAc-Glu对T淋巴细胞增殖的影响，国内外罕见报道。本文研究N_乙酰氨基葡萄糖体外作用于小鼠T淋巴细胞诱导淋巴细胞增殖。方法以T淋巴细胞为研究对象，应用MTT法，流式细胞术法考察了NAc—Glu对淋巴细胞的增殖的影响，采用Caz＋探针（Fura-3／AM）、激光共聚焦显微镜和流式细胞仪检测的方法从Ca2＋信号通路入手对NAc—Glu诱导淋巴细胞增殖的机制进行了研究。结果NAc-Glu可以诱导淋巴细胞由G0／G进入S期，使细胞的有丝分裂启动，细胞发生增殖。NAc—Glu作用下的淋巴细胞胞内Ca2＋的浓度显著增加，其中加药6h后淋巴细胞内的Ca2＋浓度最高。24h后有所下降。Ca2＋浓度的改变又影响了CaM和CaN这两种与C矿密切相关的蛋白的表达。     

D-氨基葡萄糖盐酸盐体外抗肿瘤及其免疫调节作用

目的研究D-氨基葡萄糖盐酸盐(GAH)体外抗肿瘤作用和免疫增强作用。方法MTT法观察体外GAH对肿瘤细胞生长和小鼠淋巴细胞增殖的影响,酶联免疫法(ELISA)观察GAH对淋巴细胞分泌细胞因子IL-2的影响。结果GAH明显抑制SGC-7901细胞的生长,对HepG-2、LS-174细胞生长的抑制作用较弱。GAH具有有丝分裂原样的作用,能够诱导淋巴细胞增殖并且分泌IL-2。结论GAH有一定的抗肿瘤作用和免疫增强作用。     

咖啡酸苯乙酯对小鼠CD3~+T细胞体外活化和增殖的影响

目的研究咖啡酸苯乙酯(caffeic acid phenethyl ester,CAPE)对小鼠CD3+T淋巴细胞活化及增殖的影响,探讨其作用机制。方法无菌分离小鼠淋巴结淋巴细胞,制备淋巴细胞悬液。在淋巴细胞活化实验中,分别与不同浓度的咖啡酸苯乙酯预先孵育2h后,加入促分裂原伴刀豆蛋白A(ConA),运用荧光抗体染色技术结合流式细胞术,8h后,检测T淋巴细胞早期活化标记分子CD69的表达情况;24h后,检测T淋巴细胞中期活化标记分子CD25的表达情况;在淋巴细胞增殖试验中,运用CFDA-SE标记法检测T淋巴细胞刺激48h后的增殖情况。结果CAPE(0·5、1、5、10mg·L-1)能够明显地抑制ConA刺激的小鼠淋巴细胞活化,且呈浓度依赖性;CAPE(0·5、1、5、10mg·L-1)能够明显地抑制ConA刺激的小鼠淋巴细胞增殖,且呈浓度依赖性。结论CAPE对小鼠CD3+T淋巴细胞的体外活化和增殖具有抑制作用,其作用机制可能通过同时抑制PLC-γ信号途径和MAP激酶途径,由此推理CAPE是一种潜在的有效的免疫抑制剂。     

低铅负荷对淋巴细胞膜电位影响的分析

目的:探讨不同剂量铅对淋巴细胞增殖及细胞膜电位的影响,进一步明确低铅染毒淋巴细胞膜参数表达机制。方法:将小鼠脾淋巴细胞悬液分为四组,分别为10-6mmol/L Pb Cl2染毒组、10-5mmol/L Pb Cl2染毒组、10-4mmol/L Pb Cl2染毒组,磷酸盐缓冲盐水(PBS)作为对照组;在培养不同时间段(0 h,24 h,48 h,72 h)的细胞悬液中加入不等量的单克隆抗体,同时用细胞感受性色素di BA-C4标记淋巴细胞,测定细胞膜电位,从而确定细胞膜受体表达的情况以及淋巴细胞增殖情况的变化。结果:随Pb2+染毒浓度增高及时间延长,Pb2+染毒淋巴细胞di Bh-C4荧光强度明显增加,膜内的电位出现不同程度的升高,细胞膜受体表达呈阳性变化。10-6mmol/L Pb Cl2染毒组与淋巴细胞的增殖指数比较,差异无统计学意义(P>0.05),10-5mmol/L Pb Cl2染毒组、10-4mmol/L Pb Cl2染毒组染毒72 h,淋巴细胞增殖指数与对照组比较,差异有统计学意义(P<0.05)。结论:Pb Cl2染毒对淋巴细胞膜电位表达具有时间依赖性和饱和性;浓度>10-6mmol/L Pb Cl2染毒淋巴细胞具有抑制淋巴细胞增殖的作用。     

代谢活化在三氯乙烯对小鼠致敏及肝毒性中的作用

目的研究三氯乙烯(TCE)通过什么代谢通路活化后才具有致敏活性。方法以TCE和细胞色素P450(CYP450)诱导剂(乙醇和苯巴比妥)分别及联合给小鼠染毒,测定血清中丙氨酸氨基转移酶(GPT)和天冬氨酸氨基转移酶(GOT)活性;分离脾细胞体外培养,采用噻唑兰(MTT)法测定TCE所致小鼠脾淋巴细胞特异性增殖反应和细胞毒性,并观察体外培养过程中加入代谢酶抑制剂SKF525A和氨氧乙酸(AOAA)后对上述效应的影响。结果TCE致敏组小鼠脾淋巴细胞与TCE共孵育后,细胞相对数(79±10)%明显高于溶剂对照组(63±11)%,差异有统计学显著性(P<0.05),在培养液中加入β裂合酶抑制剂AOAA后,这种抗原特异性淋巴细胞增殖反应消失;而乙醇诱导+TCE组和苯巴比妥诱导+TCE组小鼠脾淋巴细胞未出现TCE特异性增殖反应。溶剂对照组、TCE致敏组、乙醇诱导+TCE组和苯巴比妥诱导+TCE组小鼠脾淋巴细胞与TCE+SKF共培养后,细胞相对数均明显高于TCE单独培养的淋巴细胞,差异有统计学显著性(P<0.05)。乙醇诱导+TCE组血清GPT活性(49.5±8.4)μmol·min-1·L-1和苯巴比妥诱导+TCE组血清GPT,GOT活性(47.3±9.9)和(170±36)μmol·min-1·L-1均明显高于溶剂对照组(34.7±2.1)和(117±34)μmol·min-1·L-1,差异有统计学显著性(P<0.05),而TCE致敏组小鼠血清GPT和GOT活性与溶剂对照组相比均无显著性差异(P>0.05)。结论TCE谷胱甘肽结合通路的代谢产物巯基烯酮类物质具有致敏活性,可能是TCE致敏小鼠的特异性半抗原,而TCE氧化通路的代谢产物是产生细胞毒性和肝损伤的主要物质,乙醇和苯巴比妥能够增加TCE的肝脏毒性。     

MTT法检测卵蛋白刺激哮喘小鼠脾淋巴细胞增殖最佳实验条件的研究

目的探讨MTT法检测卵蛋白(OVA)刺激哮喘小鼠脾淋巴细胞增殖的最佳实验条件。方法制备OVA诱导哮喘小鼠模型,分离脾淋巴细胞。接种不同浓度的脾淋巴细胞,在不同培养时间点测定吸光度(A)值,确定最佳细胞浓度和检测时间。观察不同浓度OVA对脾淋巴细胞增殖的影响。结果最佳脾淋巴细胞接种浓度为2×106~4×106cells/ml,最佳检测时间为48 h。培养24和48 h时,细胞浓度为1×106~4×106cells/ml,A值与细胞浓度呈线性关系(r0.99)。10μg/ml OVA可诱导脾淋巴细胞显著增殖,100μg/ml OVA反而抑制脾淋巴细胞增殖。结论 MTT法可用于检测哮喘小鼠的脾淋巴细胞增殖,细胞浓度与A值呈线性关系。OVA浓度是影响脾淋巴细胞增殖的重要因素。     

杨梅素对淋巴细胞活化及增殖的影响

目的研究杨梅素(myricetin)对小鼠T细胞活化及增殖的影响,探讨其作为免疫调节药物开发的可能性并提供相关实验依据。方法无菌分离小鼠淋巴结细胞,加入不同浓度的杨梅素预先孵育1h,用多克隆刺激剂刀豆蛋白(ConA)刺激T细胞活化,利用荧光标记的单克隆抗体双染技术,流式细胞仪检测杨梅素对小鼠CD3+T细胞CD69表达的影响;采用3H-TdR参入法检测杨梅素对淋巴细胞增殖的影响,采用半定量RT-PCR技术从mRNA水平检测杨梅素对IL-2mRNA表达的影响。采用ELISPOT检测杨梅素对IFN-γ分泌的影响。结果杨梅素能抑制T细胞早期活化标志CD69的表达,并能抑制淋巴细胞增殖反应,同时对淋巴细胞活化后IL-2 mRNA的表达及IFN-γ的分泌也有抑制作用。结论杨梅素对淋巴细胞的活化增殖反应具有抑制作用。     

雷帕霉素对小鼠T淋巴细胞的体外作用

目的 研究雷帕霉素对小鼠T淋巴细胞体外的增殖、白细胞介素2(IL-2)表达及细胞周期的影响.方法 将C57BL/6小鼠脾脏制备成脾单个核细胞,使用免疫磁珠法分选出小鼠T淋巴细胞.T细胞分别加入0、10、20、30和40 ng/ml梯度浓度的雷帕霉素培养液培养72 h后,采用MTT法及ELISA法测定各组细胞的增殖情况及IL-2表达情况;用流式细胞仪测定40 ng/ml雷帕霉素浓度组及对照组(0 ng/ml)细胞周期的变化情况.结果 用雷帕霉素培养液培养细胞时,细胞增殖及IL-2的表达均受到抑制(P＜0.01).随药物浓度增加,细胞增殖及IL-2表达受抑制越明显(P＜0.01);细胞周期分析显示加入雷帕霉素培养的T淋巴细胞与未使用药物刺激者相比,G0G1期细胞的比例升高(P＜0.01),S期降低(P＜0.01).结论 在体外雷帕霉素对小鼠T细胞的增殖、IL-2的表达起抑制作用,且随浓度增加,抑制作用增强;雷帕霉素将小鼠T细胞抑制在G0G1期.     

Differential lymphocyte growth-modifying effects of oxidants: changes in cytosolic Ca+2

An increase in the concentration of cytosolic Ca+2 ([Ca-2]i) is among the earliest changes seen in mitogen-stimulated lymphocytes and is a consequence of signal transduction which usually results in the initiation of cell cycle progression. However, increased [Ca+2]i has also been correlated with cytotoxicity. We have determined whether modulations of [Ca+2]i are involved in the functional inactivation of cells observed with sublethal concentrations of oxidants. Specifically, [Ca+2]i was measured in mouse splenic lymphocytes that were treated with different oxidants in order to determine if oxidative stress interferes with mitogen-stimulated increases in [Ca+2]i, if oxidants themselves modulated [Ca+2]i, and, if so, whether such Ca+2 modulations by oxidants had stimulatory or inhibitory effects on the response of lymphocytes to mitogens. The oxidants employed were copper phenanthroline (CuP; surface thiol oxidizer), N-ethyl maleimide (NEM; permeant thiol alkylator), hydrogen peroxide (H2O2; generates hydroxyl radical within the cell), and radiation (Cs137; generates hydroxyl radical by radiolysis). Growth of all treated cells was equally inhibited upon stimulation with Con A or PMA/A23187, suggesting that all the oxidants inhibited cell functions required distal in activation to the transduction pathway utilized by Con A but bypassed by PMA/A23187. Doses of CuP, NEM, and radiation which fully inhibited Con A-stimulated proliferation had little effect on resting or mitogen-stimulated changes of [Ca+2]i, but H2O2 doses which fully inhibited proliferation increased [Ca+2]i in unstimulated cells and prevented the increase normally caused by Con A. Both intra- and extracellular Ca+2 contributed to the increased [Ca+2]i seen in unstimulated cells. An elevated [Ca+2]i was sufficient to reduce responsiveness, since pharmacologically increasing the [Ca+2]i with the ionophore A23187 rendered lymphocytes less responsive to Con A. Unlike A23187, H2O2 was unable to synergize with PMA, suggesting that the H2O2-induced increase of [Ca+2]i delivered predominantly negative signals to the cell. The results also suggest that [Ca+2]i utilization by Con A versus PMA-activated lymphocytes must be different. When cells were treated with H2O2 under conditions where intracellular and extracellular Ca+2 were chelated with BAPTA and EGTA, respectively, the response to Con A was restored. Under these conditions, higher concentrations of H2O2 were required to inhibit the response to Con A. Our results indicate that signal transduction may be compromised in cells treated with H2O2, but not in cells treated with CuP, NEM, or radiation.(ABSTRACT TRUNCATED AT 400 WORDS)     

锌对大鼠成骨细胞内游离钙离子浓度和钙调蛋白活性的影响

实验旨在阐明锌对体外培养大鼠成骨细胞胞内游离钙离子浓度 ( [Ca2 +]i)及钙调蛋白 (CaM)活性的影响 .各研究因素分别作用于成骨细胞 3d或短时作用后 ,分别测定 [Ca2 +]i 和CaM活性 ;采用CaM PDE实验体系深入研究锌对CaM可能存在的潜在作用 .结果表明 :无论是长期或短时作用 ,锌对大鼠成骨细胞 [Ca2 +]i 及CaM活性均无影响 ;在CaM PDE实验体系中 ,低浓度锌可以激活CaM ,但高浓度抑制CaM ,这可能与锌竞争结合CaM上钙结合位点有关 .在本实验条件下 ,锌对Ca2 +/CaM信号途径无影响 ,但具有潜在激活或抑制CaM的生物学效应     

灯盏花素对人脐静脉内皮细胞胞内Ca~(2+)水平的调控作用

目的探讨灯盏花素对培养的人脐静脉内皮细胞(HUVECs)胞内Ca2+水平([Ca2+]i)的调控作用。方法采用新一代Ca2+荧光探针Fluo-3/AM标记培养的HUVECs,激光共聚焦显微镜检测细胞胞内钙荧光信号,观察灯盏花素对培养的HUVECs胞内Ca2+水平的调控作用。结果在胞外有Ca2+或无Ca2+的情况下,灯盏花素均可引起[Ca2+]i的短暂性升高;灯盏花素的Ca2+释放作用与钙泵抑制剂CPA存在着交迭;灯盏花素能够抑制由KCl所引起的[Ca2+]i的升高;灯盏花素对胞内Ca2+池耗竭后胞外复Ca2+所引起的钙内流无明显阻断作用。结论灯盏花素可引起胞内Ca2+池的Ca2+释放,其释放的Ca2+来自CPA敏感的Ca2+池。灯盏花素也可抑制经电压依赖性Ca2+通道的Ca2+内流,对Ca2+池耗竭后引起的Ca2+内流通道无明显阻断作用。     

Participation of Ca2+/calmodulin during activation of rat neutrophils by polychlorinated biphenyls

The effects of Ca2+ and Ca2+/calmodulin on the polychlorinated biphenyl (PCB)-induced activation of phospholipase A2 (PLA2) in rat neutrophils were examined. The commercial PCB mixture Aroclor 1242 induced activation of PLA2 and promoted an increase in the intracellular free calcium concentration ([Ca2+]i). Bromoenol lactone (BEL), an inhibitor of the Ca2+-independent PLA2 isoform (iPLA2) activated by PCBs, did not abrogate the increase in [Ca2+]i, suggesting that this change in Ca2+ concentration is not downstream from the activation of iPLA2. TMB-8 [8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate], a blocker of the release of intracellular Ca2+, decreased Aroclor 1242-induced stimulation of PLA2 with a maximal inhibition of 17% at 50 microM. These two results suggest little direct dependence between the PCB-induced activation of iPLA2 and increase in [Ca2+]i. Calmidazolium and W7 [N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide], two chemically distinct calmodulin inhibitors, inhibited Aroclor 1242-induced PLA2 activity, whereas trifluoperazine (TFP), another inhibitor of calmodulin, had no effect at noncytotoxic concentrations. Thus, activation of PLA2 is dependent, in part, on calmodulin. Furthermore, both TFP and Aroclor 1242 inhibited neutrophil degranulation stimulated by the bacterial peptide formyl-methionyl-leucyl-phenylalanine. These results raise the possibility that some of the effects of PCBs on neutrophil function can be explained by effects on Ca2+/calmodulin-dependent processes.     

Inhibition by fenamates of calcium influx and proliferation of human lymphocytes.

1. Flufenamic and tolfenamic acids have recently been shown to inhibit receptor-mediated calcium influx in human neutrophils. The present work was designed to study the effects of these two nonsteroidal anti-inflammatory drugs on human peripheral blood lymphocyte activation. 2. Peripheral blood mononuclear cells (PBMNCs; containing 90% lymphocytes) were stimulated by mitogen concanavalin A (Con A) or by a combination of an inhibitor of microsomal Ca(2+)-adenosine triphosphatase thapsigargin (TG) and phorbol myristate acetate (PMA). The effects of the two fenamates on cell proliferation were compared with respective changes in calcium metabolism. 3. Flufenamic and tolfenamic acids (10-100 microM) inhibited both Con A and TG + PMA-induced [3H]-thymidine incorporation in a dose-dependent manner. At the same concentration range, the two fenamates inhibited the increase in intracellular free calcium concentration induced by Con A or TG + PMA. This effect was due to inhibition of calcium influx whereas calcium release from intracellular stores remained unaltered. 4. The inhibition of divalent cation influx was confirmed by showing that fenamates inhibited TG + PMA-induced Mn2+ influx. 5. The inhibitory effects of fenamates on PBMNC proliferation and Ca2+ influx were qualitatively similar with those of SK&F 96365, an earlier known inhibitor of receptor-mediated calcium entry. Ketoprofen, a chemically different prostaglandin synthetase inhibitor did not show similar suppressive effects on PBMNCs. 6. The data suggest that flufenamic and tolfenamic acids suppress proliferation of human peripheral blood lymphocytes by a mechanism which involves inhibition of Ca2+ influx and is not related to inhibition of prostanoid synthesis.     

Involvement of Ca2+-dependent pathways in the inhibition of human natural killer (NK) cell activity by cortisol

The role of Ca2+ as a second messenger of the glucocorticoid inhibition of human natural killer (NK) cell activity was evaluated using Ca2+ entry blockers (verapamil and its desmethoxy derivatives LU46973 and LU47093), calmodulin antagonists (pimozide and two naphthalensulfonamide derivatives, W-7 and W-13), the Ca2+ channel agonist BAY K 8644 and the calcium ionophore A23187. Peripheral blood mononuclear (PBM) cell preparations were incubated for 20 h with 1 x 10(-6) M cortisol and these agents in various combinations (concentration range: 1 x 10(-9) -1 x 10(-5) M) and then assayed in a direct 4-h cytolytic assay using 51Cr-labeled K 562 target cells. Exposure to cortisol led to a significant reduction of NK cell activity (about 50% vs. spontaneous activity). Ca2+ entry blockers and calmodulin antagonists were per se minimally effective, but significantly enhanced cortisol-dependent inhibition of NK cell activity. Raising extracellular Ca2+ by CaCl2 or intracellular Ca2+ by the calcium channel agonist BAY K 8644 or the ionophore A23187 resulted in an appreciable reduction of these effects. Similar results were obtained when these substances were added to monocyte-depleted or NK cell-enriched suspensions exposed to cortisol. Our data are consistent with the view that extra- and intracellular Ca2+ plays a role in the control of human NK cell activity. It is also conceivable that both calcium flux into the cell and the calcium calmodulin system are involved in the cortisol-induced inhibition of natural cytotoxicity.     

Cortisol secretion induced by substance P from bovine adrenocortical cells and its inhibition by calmodulin inhibitors.

When primary cultured bovine adrenocortical cells were treated with substance P (SP) at concentrations higher than 10 pM, cortisol output increased in a dose-dependent fashion. Although other neurokinins, such as neurokinin A (NKA) and neurokinin B (NKB), were also effective in secreting cortisol, SP was the most potent among the tested neurokinins, the potency order being SP greater than NKA much greater than NKB. This suggests that the NK-1 type receptor on adrenocortical cells may be the site of action of SP on cortisol secretion. The maximal response in SP-induced cortisol secretion was comparable to that elicited by adrenocorticotropic hormone (ACTH). SP-induced cortisol secretion was dependent upon extracellular Ca2+ concentrations, and 45Ca2+ uptake into adrenocortical cells treated with SP was long-lasting. While, in the case of ACTH, 45Ca2+ uptake proceeded transiently, the increase in intracellular cAMP content was much greater compared with that of SP. Although KT-5720, an inhibitor of protein kinase A, inhibited potently ACTH-induced cortisol secretion, SP-induced secretin was not affected by this inhibitor at all. On the other hand, calmodulin inhibitors, such as calmidazolium, trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, were not more effective in inhibiting SP-induced cortisol secretion than secretion induced by ACTH. The present study indicates that SP may be one of the physiological stimulants of cortisol secretion and that an increase in intracellular Ca2+ concentration and the subsequent activation of calmodulin may precede SP-induced cortisol secretion.