电针大鼠的血清中淋巴细胞转化抑制因子的作用机制分析

本室以前的工作表明:电针(2H_z,3V,30min/d)刺激 SD 大鼠双侧足三里-三阴交,5d后,大鼠血清中产生出淋巴细胞转化抑制因子,本工作对此抑制因子的作用机制进行了初步研究,主要结果如下:(1)电针大鼠的血清不仅显著抑制 Con A 刺激的小鼠淋巴结 T 淋巴细胞转化,还可显著抑制 Con A 刺激的小鼠胸腺细胞和脾脏 T 淋巴细胞转化;同时也发现电针大鼠的血清能显著抑制脂多糖(LPS)刺激的小鼠淋巴结 B 淋巴细胞转化。提示此淋巴细胞转化抑制因子对不同淋巴器官及不同类型的淋巴细胞无选择性作用。(2)将电针大鼠的血清同小鼠淋巴结细胞培养1h,电针大鼠的血清就可显著抑制 Con A 刺激的 T 淋巴细胞转化;将小鼠淋巴结细胞同 Con A 预培养30min,电针大鼠的血清的抑制作用便消失,提示电针大鼠血清中淋巴细胞转化抑制因子作用于 Con A 刺激 T 淋巴细胞活化的早期阶段,同时也排除了此抑制因子的细胞毒作用。(3)电针大鼠的血清显著抑制蛋白激酶 C(PKC)激活剂 PMA和 PMA 加 ca~(2+)通道 A23187刺激的小鼠淋巴结细胞转化,提示淋巴细胞转化抑制因子通过抑制 PKC 的活性或抑制 PKC 介导的细胞活化通路,抑制有丝分裂原刺激的淋巴细胞转化。     

束缚应激大鼠血清淋巴细胞转化抑制因子的研究

为研究应激对淋巴细胞转化的影响,将 SD 大鼠四肢束缚于支架上,仰卧位,室温(20℃)下维持20h,对照组留置原饲养笼中,不予惊动。然后在乙醚轻麻下穿刺心脏取血,肝素化后密度梯度离心分离淋巴细胞,或待凝后分离血清。结果表明,应激大鼠外周血淋巴细胞对刀豆素(Con A)诱导的转化反应明显下降(p<0.01,n=8,ANOVA),而且应激大鼠血清可明显抑制正常小鼠淋巴细胞转化,这提示应激大鼠血清中可能存在某种具有抑制淋巴细胞转化的活性物质。进一步的分析实验表明,这种血清经加热56℃(30min),30%甲醇或透析(透析袋孔径阻滞分子量为6000)处理,抑制活性均不受影响;但经加热100℃(3min),80%甲醇或胰蛋白酶(64/μg/ml)处理,抑制活性丧失。提示这种抑制活性物质很可能是一类蛋白质。     

GABA能神经元对抗束缚应激后血清淋巴细胞转化抑制因子的产生

我们以前的实验证明,大鼠或小鼠经束缚应激10h后,血清中出现一类淋巴细胞转化抑制因子。它的产生依赖于中枢神经系统的活动。本研究主要观察中枢神经系统中γ-氨基丁酸(GABA)能神经元在应激后血清淋巴细胞转化抑制因子产生中的作用。结果表明,给小鼠腹腔注射 GABA 降解酶抑制剂氨氧乙酸(AOAA,25mg/kg),升高脑内GABA 含量后,几乎完全阻断应激后血清中淋巴细胞转化抑制因子的产生。安定可增强GABA 与 GABA_A 受体的亲和性,给小鼠腹腔注射安定20mg/kg,应激后血清淋巴细胞转化抑制因子的产生也有明显降低。相反,注射 GABA 合成和释放抑制剂3-巯基丙酸(3-MP 24mg/kg),降低脑内GABA能神经元功能,可加强应激后血清淋巴细胞转化抑制因子的产生。以上实验结果从正、反两方面说明应激时脑内GABA能神经元具有对抗血清淋巴细胞转化抑制因子产生的作用。     

促肾上腺皮质激素释放因子介导低氧应激抑制淋巴细胞转化的实验研究

本实验以模拟高原低氧方法观察大鼠淋巴细胞对丝裂原（ＣｏｎＡ）的反应性及促肾上腺皮质激素释放因子（ＣＲＦ）介导急性低氧的免疫调节作用。实验结果表明：急性低氧可抑制大鼠外周血淋巴细胞转化,高原土著动物高原鼠兔（Ｏｃｈｏｔｏｎａｃｕｒｚｏｎｉａｅ）则不表现这种低氧抑制作用;肾上腺完整和肾上腺摘除大鼠第三脑室给予外源性ＣＲＦ１μｇ,表现出与低氧作用类似的淋巴细胞转化下降现象;低氧时第三脑室给予高效价ＣＲＦ抗血清可部分阻断低氧抑制作用。放射免疫分析法检测外周血浆中ＣＲＦ和皮质酮水平显示急性低氧大鼠血浆ＣＲＦ、皮质酮水平均升高,高原鼠兔无明显变化。因而,本研究提示：急性低氧可抑制淋巴细胞转化,ＣＲＦ是介导急性低氧抑制淋巴细胞转化的一种因子,而与肾上腺皮质激素的变化可能无关,高原鼠兔免疫功能对低氧不敏感。     

促肾上腺皮质激素释放因子介导低氧应激抑制淋巴细胞转化…

本实验以模拟高原低氧方法观察鼠淋巴细胞对丝裂原（ＣｏｎＡ）的反应性及促肾上腺皮质激素释放因子（ＣＲＦ）介导急性低氧的免疫调节作用。实验结果表明：急性低氧可抑制大鼠外用周血淋巴细胞转化,高原土著动物高原鼠兔（Ｏｃｈｏｔｏｎａ ｃｕｒｏｎｉａｅ）则不表现这种低氧作用;肾上腺完整和肾上腺摘除大鼠第三脑室给予外源性ＣＲＦ１μｇ,表现出与低氧作用类似的淋巴细胞转化下降现象;低氧时第三脑室给予高效价ＣＲＦ抗血     

应激抑制淋巴细胞转化的时间效应

本研究吵缚方法使大鼠接受应激刺激,然后分别取大鼠应激３、６、１２、１８ｈ和解除束缚后１２、２４、４８、７２、９６ｈ的淋巴结、脾脏提取物和血清,与刀豆素Ａ同时加入正常大鼠肠系膜淋巴结细胞悬液中育７２ｈ后用噻唑蓝（ＭＴＴ）比色分析法检测肠系膜淋巴结细胞的转化,来应激抑制淋巴细胞转化作用的出现和消失过程。结果如下：（１）应激３和６ｈ大鼠的淋巴结、脾脏提取物和血清对淋巴细胞的转化都没有明显的影响;（２）应     

间断性低氧对大鼠淋巴细胞转化的影响

目的: 探讨间断性低氧对机体免疫反应的影响.方法: 以模拟海拔高度间断性低氧(4 h/d)模型观察大鼠脾淋巴细胞对丝裂原(Con A)的反应性.结果: 与对照相比,5 km急性低氧4 h大鼠淋巴细胞的转化率下降25.43%(P<0.05) ,间断性低氧2、5、15 d后淋巴细胞转化率分别为97.03%、104.5%和99.55%,与对照组无明显差异.2 km间断性低氧(4 h/d)1、2、5、15 d,大鼠脾淋巴细胞转化率分别为93.19%、96.43%、99.03%和100.54%,与对照组无明显差异.脾单个核细胞DNA含量显示, 5 km急性低氧4 h DNA含量明显下降(76.22%±7.06%,P<0.05),间断性低氧5 d和15 d后与对照组无显著差异.结论: 急性低氧抑制淋巴细胞的转化,并随低氧的加重而增加,重复间断性低氧暴露其抑制作用减弱,引起大鼠淋巴细胞转化产生适应.推测免疫适应与HPA轴的适应有关.     

急性低氧下去甲肾上腺素对大鼠淋巴细胞转化的调节作用

本研究以模拟高原低氧方法,观察低氧作用于大鼠细胞免疫功能以及去甲肾上腺素对免疫作用的调节机制。实验结果：与对照相比,７ｋｍ急性低氧２４ｈ淋巴细胞转化下降４１％（Ｐ〈０．０１）;５ｋｍ低氧暴露时间为７ｄ,２０ｄ时,低氧抑制淋巴细胞转化,分别下降３４％和６０％（Ｐ〈０．０１）,侧脑室注入５ｎｍｏｌ／Ｌ ＮＥ,淋巴细胞转化比对照下降２９％（Ｐ〈０．０１）,７ｋｍ１０ｈ低氧暴露时,侧脑室注入酚妥拉明２５μ     

Possible mechanisms of action of an anti-Pasteurella pestis factor

Anti-Pasteurella pestis factor (APF) inhibited bacterial growth, but there was no evidence that APF from either mouse or guinea pig or selected fatty acids physically disrupted the cell wall. The fatty acids selected were representative of those found in APF. APF inhibited oxidation of beta-d-glucose but not oxidation of glucose-6-phosphate, whereas fatty acids inhibited the oxidation of glucose-6-phosphate but not oxidation of beta-d-glucose. The oxidation of 6-phosphogluconic acid was inhibited by both APF and free fatty acids. Furthermore, APF and potassium laurate inhibited 6-phosphogluconic dehydrogenase in a cell-free extract of P. pestis strain E.V. 76. No evidence of beta-d-glucose or glucose-6-phosphate dehydrogenases was found in the cell-free extract. The results suggested that APF and fatty acids may kill P. pestis by inactivating 6-phosphogluconic acid dehydrogenase. The effects of these agents on other enzyme systems were not excluded.     

In vitro stimulation of natural killer (NK) cells by soluble factor(s) generated in antigen-stimulated rhesus monkey peripheral blood lymphocyte cultures.

Peripheral blood lymphocytes from rhesus monkeys (Macaca mulatta) sensitized to keyhole limpet hemocyanin (KLH), when stimulated in vitro with KLH, developed natural killer (NK) cell activity that was assayed with Rous Sarcoma virus-transformed marmoset fibroblasts as targets in a 4-hr 51Cr-release assay. The supernatant fluids from 24- to 25-hr KLH-activated cultures were capable of stimulating NK development in nonsensitive lymphocyte cultures. The effector cells were neither macrophages nor B cells (plastic and nylon-wool nonadherent) and did not form E-rosettes with neuraminidase-treated sheep red blood cells. Cultures depleted of EA-rosetting cells, i.e., Fc-receptor-bearing lymphocytes, were incapable of generating NK activity when stimulated in vitro. Kinetic studies showed that peak DNA synthesis, as measured by 3H-T incorporation, preceded maximum cytotoxicity. Elimination of dividing cells by 5-bromo-2'deoxyuridine (BrdU) and light treatment during the interval from day 1 to day 4 inhibited the development of cytotoxicity on day 7. Cell replication was required for the induction of NK cells with KLH as well as with antigen-activated culture supernatant fluids. When cultures were left unstimulated for 4 days, NK activity could not be developed subsequently either by adding antigen, mitogen (PHA), or supernatant fluids from activated cultures.     

Possible mechanisms of positive inotropic action of synthetic human calcitonin gene-related peptide in isolated rat atrium

The effect of synthetic human calcitonin gene-related peptide (hCGRP) on the isolated and electrically driven left atria of rats were investigated. The peptide at concentrations of 3 X 10(-9)-3 X 10(-7) M produced positive inotropic effects on the left atria in a dose-dependent manner. Verapamil (10(-5) M) and adenosine (10(-4) M) reduced the positive inotropic effect of hCGRP at concentrations of 3 X 10(-9) and 3 X 10(-8) M, but not at that of 3 X 10(-7) M. Ouabain (5 X 10(-5) M) inhibited the effect of hCGRP in concentrations of 3 X 10(-7) and 3 X 10(-8) M, but not in that of 3 X 10(-9) M. Simultaneous pretreatment with verapamil (10(-5) M) and ouabain (5 X 10(-5) M) suppressed the positive inotropy by hCGRP at all concentrations tested. On the other hand, tetrodotoxin (10(-6) M) potentiated only the positive inotropic effect of 3 X 10(-7) M hCGRP. Metoprolol (10(-7) M) and theophilline (10(-3) M) did not affect the inotropic effect of hCGRP. These results suggest that the positive inotropic effect of hCGRP is not mediated by beta-adrenoceptors but by two distinct mechanisms of action, which was inhibited by verapamil but not by ouabain (facilitation of Ca++ influx in lower concentrations of hCGRP) and which was blocked by ouabain but not by verapamil and potentiated by tetrodotoxin (inhibition of Na+/Ca++ exchange mechanism at higher concentrations of hCGRP).     

Functional architectonics of neuronal antinociceptive mechanisms during the electroacupuncture method of reflex action

The peculiarities of neurone bioelectric activity of sensory thalamic nuclei under electroacupuncture (EAP) stimulation have been studied in acute experiments on cats. EAP stimulation has been established to change spontaneous and evoked activity of neurones of sensory thalamic nuclei, that testifies to the development of a new functional state. The functional state of the cortex, in particular the second somatosensory region has been shown to determine the nature of neurone activation of sensory thalamic nuclei during the EAP stimulation. Schemes of possible organization of functional pools realizing the mechanisms of inhibition of nociceptive signals on central neurones during EAP way of reflex stimulation are suggested.     

Phytohaemagglutinin stimulation of rat thymus lymphocyte glycolysis

Glucose disappearance and lactate production by rat thymocytes are stimulated significantly 45 min after addition of phytohaemagglutinin or concanavalin A and the stimulated rate is sustained for at least 8 h.Changes in the steady-state concentration of glycolytic intermediates that occur at non-equilibrium steps during the increased rate of glycolytic flux indicate that the glucose carrier, hexokinase and phosphofructokinase are potentially regulatory steps that undergo nearly simultaneous or tightly sequential activation following interaction of the cells with the mitogen.     

Macrophage migration inhibitory factor (MIF): mechanisms of action and role in disease

Macrophage migration inhibitory factor (MIF) is a unique cytokine and critical mediator of host defenses with a role in septic shock and chronic inflammatory and autoimmune diseases. Its mechanism of action is incompletely understood. Here, we attempt to correlate current knowledge on the molecular pathways of MIF activity with its functions in immunity and disease.