糖尿病大鼠心肌MDA含量,SOD和Na—K—ATP酶活性的变化

实验用四氧嘧啶破坏Ｗｉｓｔａｒ大鼠胰腺发诱导糖尿病模型，观察糖尿病大鼠心肌组织ＭＤＡ含量，ＳＯＤ和Ｎａ＾＋－Ｋ＾＋－ＡＴＰ酶活性的变化以及氧自由基清除剂（ＶｉｔＥ，亚硒酸钠）对糖尿病大鼠心肌的保护作用，结果表明：（１）糖尿病大鼠心肌组织ＭＤＡ含量显著增加（Ｐ〈０．０５），而心肌细胞膜上Ｎａ＾＋－Ｋ＾＋－ＡＴＰ酶的活性显著下降（Ｐ〈０．０１），（２）ＶｉｔＥ和亚硒酸钠能显著降低糖尿病大鼠心肌组织ＭＤ     

束缚应激对大鼠脑组织Na^＋,K^＋—ATP酶活性的影响

目的：探讨心理应激源对脑组织Ｎａ＾＋,Ｋ＾＋－ＡＴＰ酶活性的影响及发生机制,以及自由基清除剂对该酶活性的保护作用。方法：将大鼠分为对照组、束缚组和治疗组。用酶组化法制片,用图像分析仪测脑组织Ｎａ＾＋,Ｋ＾＋－ＡＴＰ酶的活性;用ＴＡＢ法测ＭＤＡ的含量。结果：束缚组和治疗组的Ｎａ＾＋,Ｋ＾＋－ＡＴＰ酶的活性;用ＴＡＢ法测ＭＤＡ的含量。明显高于对照组。治疗组Ｎａ＾＋,Ｋ＾＋－ＡＴＰ酶活性明显高于束缚组,     

磁场对AMI大鼠血SOD活性及心肌ATP含量变化的影响

本实验将大鼠随机分为五组：空白对照组、磁作用对照组、ＡＭＩ组、ＡＭＩ药物（心得安）治疗组、ＡＭＩ磁场治疗组。分别采用四氮唑蓝法和生物发光法测定各组大鼠血红细胞ＳＯＤ活性及心肌ＡＴＰ含量。结果表明：ＡＭＩ磁场治疗组血红细胞ＳＯＤ活性及心肌ＡＴＰ含量均明显高于ＡＭＩ组（Ｐ＜０．０１），磁作用对照组高于空白对照组（Ｐ＜０．０５）。初步证实，磁场对ＡＭＩ大鼠和健康大鼠心肌具有一定的保护作用，此种作用对ＡＭＩ大鼠更为明显。     

钙对心肌ATP酶的损害及镁的保护作用

本工作在大鼠心肌肌膜观察到,Mg~(2+)为心肌Na~+-K~+-ATP酶激活所不可缺少的因素,当Mg~(2+)浓度在0～6mM时,Na~+-K~+-ATP酶及Mg~(2+)-ATP酶活性与其密切相关;当超过8 mM时,ATP酶总活性不变,但Na~+-K~+-ATP酶/Mg~(2+)-ATP酶之比值增高。高浓度Ca~(2+)对于Na~+-K~+-ATP酶及Mg~(2+)-ATP酶均具有抑制作用,而提高Mg~(2+)浓度可部分地拮抗高Ca~(2+)的损伤作用。     

活性氧对心肌细胞膜ATP酶活性的影响

本实验观察了羟自由基发生系统(Fe~(2 ) H_2O_2)及过氧化氢对心肌细胞膜ATP酶活性的影响。证实羟自由基可造成心肌细胞膜ATP酶活性下降及膜脂质过氧化反应增强,其作用可被羟自由基消除剂甘露醇所对抗。过氧化氢对心肌细胞膜ATP酶也有一定直接抑制作用,但若过氧化氢通过自由基反应产生了羟自由基,则可造成心肌细胞膜ATP酶活性的更大幅度下降。     

蝮蛇抗栓酶对狗急性肺泡缺氧性肺动脉高压的影响

本文研究了蝮蛇抗栓酶对狗急性缺氧性肺动脉高压的作用。结果显示:蝮蛇抗栓酶可明显地降低肺循环阻力,剂量依赖性地减弱或抑制急性缺氧性肺血管收缩反应;但对体循环的影响较小,而且不改变PaO_2及PaCO_(2);血浆6-keto-PGF_(1α)浓度在静脉注射此酶后明显升高,但TXB_2则无显著改变。这些结果提示:蝮蛇抗栓酶可缓解缺氧性肺血管收缩痉挛,其机制可能与促进PGI_2的产生与释放有关。     

SOD与尼莫地平对窒息幼兔脑组织的保护作用

４２只新西兰幼兔，随机分为对照、窒息、窒息＋ＳＯＤ及窒息＋尼莫地平４组。各组动物均于实验开始后２４ｈ心脏取血测ＯＦＲ，测脑组织水含量，并观察脑病理改变。窒息组织与对照组比较，血清ＬＰＯ、脑水含量明显增高，血中ＳＯＤ、ＧＳＨ－Ｐｘ活力明显降低，脑病理改变明显，且窒息组ＬＰＯ与脑水含量呈正相关关系。两用药组与窒息组相比，血清ＬＰＯ、脑水含量明显减少，ＳＯＤ、ＧＳＨ－Ｐｘ活力明显增高，脑病理改变减轻。提     

Iron induces oxidative stress and may alter the rate of aging in the housefly, Musca domestica

Iron is known to play a catalytic role in the generation of oxygen free radicals in vitro. The present study was conducted in order to determine the in vivo effects of iron intake. Administration of 2 mM ferrous chloride to adult male houseflies in their drinking water significantly shortened their life span, increased the concentration of inorganic peroxides and chloroform-soluble fluorescent material, and stimulated the activity of catalase. Levels of superoxide dismutase activity, glutathione and oxygen utilization were unaffected. Overall, these results indicate that iron causes oxidative stress in vivo and may influence the rate of aging.     

四逆汤保护缺血心肌的电镜形态学观察

本文从心肌超微结构观察了四逆汤对实验性心肌缺血的保护性效应.结果表明:四逆汤组的心肌糖原指数(糖原颗粒数/线粒体)显著大于缺血组(11.3±1.8,5.8±1.1;P<0.01),提示四逆汤显著减少了因缺血而引起的糖原消耗.四逆汤组心肌线粒体比表面(1/μ)显著大于缺血组(6.33±0.17,5.35±0.26;P<0.05);四逆汤组心肌线粒体体密度(%)显著小于缺血组(33.45±2.71,37.65±1.83,P<0.01).提示四逆汤显著减轻了因缺血而引起的线粒体肿胀.四逆汤组与缺血组在心肌肌原纤维体密度(%)方面没有显著差异(P>0.05).上述结果表明四逆汤可显著减轻心肌的缺血性损伤,对缺血心肌具有保护性效应.     

The effects of repeated exposure to anoxia on intracellular calcium,glycogen and lactate in isolated ferret heart muscle

Isolated cardiac tissue from the ferret was repeatedly exposed to anoxia while perfused with glucose-containing Tyrode solution. In one series of experiments, papillary muscles were injected with aequorin to measure intracellular Ca²⁺. On the first exposure to anoxia, the Ca²⁺ transients often increased, but on subsequent exposures this increase disappeared and eventually the Ca²⁺ transients declined on exposure to anoxia. This decline in the Ca²⁺ transients could be converted back to an increase by a 1 h exposure to an elevated (×5) glucose concentration. Exposure of aerobic muscles to 10 mM lactic acid caused a similar increase in the Ca²⁺ transients to that seen in early exposures to anoxia. In a second series of experiments, performed on Langendorff-perfused hearts, measurements were made of glycogen concentration preceding, and lactate production during, exposures to anoxia. At a constant level of glucose, glycogen concentration and lactate production were found to decline on repeated exposures to anoxia, and both were increased after a period of elevated glucose and reduced stimulation frequency. These results suggest that the response of the Ca²⁺ transients to anoxia is dependent on the metabolic status of the muscle. The increase in the Ca²⁺ transients during an early eposure to anoxia may be a consequence of lactic acid production due to accelerated glycolysis. Repeated exposures to anoxia reduce glycogen concentration and lactate production and this reduces the rise in the Ca²⁺ transients.     

Effect of exercise on tissue anti-oxidant capacity and heart electrical properties in male and female rats

We studied the changes in the anti-oxidant capacity of tissues, such as heart, liver, and blood in male and female rats, as a parameter for evaluating oxidative stress after either a prolonged (210 min) or an exhausting bout of swimming. Furthermore, we also investigated exercise-induced changes in the electrophysiological properties, measured in vitro, of papillary muscle fibres. Small decreases of anti-oxidant capacities after prolonged exercise [0.10 (SEM 0.04) in heart, 0.43 (SEM 0.19) in liver, 0.22 (SEM 0.05) in blood] and greater decreases after exhausting exercise [0.23 (SEM 0.04) in heart, 0.90 (SEM 0.29) in liver, 0.34 (SEM 0.04) in blood] were found in tissues from the male rats. For the female rats, similar changes were found only in the blood [0.11 (SEM 0.07) and 0.35 (SEM 0.06) for prolonged and exhausting exercise, respectively]. Liver and heart anti-oxidant capacity remained unchanged after prolonged exercise, while after exhausting swimming it underwent a decrease almost the same as found in the male rats, though the swimming time to exhaustion (endurance capacity) was much greater [706 (SEM 10) min and 444 (SEM 32) min for the females and males, respectively]. The duration of the action potential, recorded from papillary muscle fibres, underwent changes related to the decreases in heart anti-oxidant capacity. In fact, the action potential duration (APD) was shorter only in preparations from the male rats after prolonged exercise, but in all preparations after exhausting exercise. After such exercise, the APD was similar for the male and female rats [37.1 (SEM 3.4) ms and 37.0 (SEM 3.6) ms, respectively]. Such a pattern was independent of stimulation frequency, since it was found substantially unchanged when the frequency was increased from 1 to 5 Hz. We concluded that the different susceptibilities to the effects of physical exercise, exhibited by tissues from these male and female rats might have been related to different capacities to oppose oxidative stress effectively.     

Effect of age and ambient temperature on n-pentane production in adult housefly, Musca domestica

The objective of this study was to examine the relationship between lipid peroxidation and aging in the male housefly. Metabolic rate of flies is known to be higher and life span shorter at elevated ambient temperature. Evolution of n-pentane and level of thiobarbituric acid (TBA) reactive material were used as indicators of lipid peroxidation. n-Pentane accumulated by houseflies in vivo and by whole body homogenates of houseflies, in response to tert-butyl hydroperoxide (1 mM), increased with age. n-Pentane accumulation in vivo was markedly higher at higher ambient temperature. Furthermore, n-pentane generated by flies in vivo and by fly homogenates in vitro tended to be lower in flies raised at a lower ambient temperature. TBA-reactive material, elicited by tert-butyl hydroperoxide, was augmented in older flies, but no significant difference was found between flies aged at different ambient temperatures. Analysis of fatty acids in housefly homogenates indicated an age-associated increase in the ratio of polyunsaturated to saturated fatty acids.     

The combined effects of orthostatic and mental stress on heart rate,T-wave amplitude,and pulse transit time

The purpose of the present study was to determine whether cardiovascular reactivity to mental stress may be comparable in sitting and standing postures. Fifteen healthy males performed two 1-min mental arithmetic tasks, either while sitting or while standing, in counterbalanced order. Heart rate, pulse transit time, and T-wave amplitude were recorded in the last 10 s of the minute before, during, and after the mental arithmetic. Reactivity scores for each of the dependent measures were computed by calculating the percentage change from baseline values. Data were analyzed with multivariate and univariate repeated measures analysis of variance. Heart rate reactivity to the combination of orthostatic and mental stress was greater than to either stressor alone. Cardiac-sympathetic reactivity was greater in response to orthostatic than to mental stress as revealed by greater changes in T-wave amplitude and pulse transit time in response to the former. No additional decreases in T-wave amplitude, in response to mental stress, were observed during standing, but pulse transit time decreased in the same situation. However, no changes in pulse transit time in response to mental stress were observed in the sitting position. These results demonstrate that cardiovascular reactivity to mental stress depends on the body position in which the stressor is encountered.     

The effects of water immersion and restraint stress on the expressions of apelin,apelin receptor (APJR) and apoptosis rate in the rat heart

Apelin has been identified as an endogenous ligand of the orphan G-protein-coupled apelin receptor (APJR). These receptors are widely expressed in the central nervous system and periphery and play a role in the regulation of fluid and glucose homeostasis, feeding behavior, vessel formation, cell proliferation and immunity. We aimed to investigate whether water immersion and restraint stress have effects on apelin and APJR expression and apoptosis in heart tissue of male Wistar rats. The cardiac tissues were obtained from control, water immersion and restraint stress (WIRS) and apelin antagonist (F13A) + WIRS groups of rats and embedded in paraffin wax. Immunohistochemical staining methods were used to localize apelin, APJR and TUNEL immunopositive cells. H-SCORE was used for semi-quantitative determinations. Apelin protein levels were determined by Western blot in the cardiac tissues and plasma corticosteroid levels were measured by enzyme immunoassay (EIA). Apelin immunolocalization was found especially in endothelial cells and mast cells and faintly in cardiomyocytes, APJR immunostaining was shown in endothelial cells and cardiomyocytes, and TUNEL reaction was observed in endothelial cells and in some fibroblasts. Apelin expression was significantly increased in the WIRS and F13A + WIRS groups compared to the control group. The APJR reaction was similar in all groups. The number of TUNEL-positive cells was significantly higher in the F13A + WIRS group than that of the control group. Our study showed that WIRS for 6 h increased plasma corticosterone levels and cardiac apelin expression in rats. The increased levels of apelin inhibited stress-induced apoptosis in heart. These results may be important for the therapeutic approach to a variety of stress-related heart disease.     

钙离子浓度变化对大鼠缺血心室致颤阈值的影响及其与cAMP、cGMP及ATP的关系

本文目的是观察不同钙离子浓度([Ca~(2 )])对急性局部缺血大鼠心脏室颤阈(VFT)的影响及其与心肌cAMP、cGMP和ATP含量变化的关系。结果表明,[Ca~(2 )]与缺血心脏VFT下降幅度呈正相关(r=0.7998,p<0.05);而[Ca~(2 )]与缺血心肌cAMP/cGMP比值、ATP含量则呈负相关(分别r=-0.887、r=-0.864,均p<0.05);缺血心脏VFT下降幅度与cAMP/cGMP比值亦呈显著负相关(r=-0.992,p<0.01),提示心肌细胞内游离Ca~(2 )水平可能是缺血心室易颤性(VV)的决定因素;cAMP水平或cAMP/cGMP比值则可能是通过影响Ca~(2 )内流而起作用的间接因素;而ATP贮量对缺血心脏VFT下降可能有一定保护作用。