不同类型磁场对细胞作用的生物学研究

本文就不同参数的磁场的细胞生物学效应研究进行了综述 ,总结了不同类型不同物理参数的磁场对细胞生物学效应的研究成果 ,结合实验结果对磁场生物学效应的可能物理机制进行了初步探讨 ,并对磁场的细胞生物学效应的研究前景进行了展望。     

Oxidative stress during exercise: Implication of antioxidant nutrients

Research evidence has accumulated in the past decade that strenuous aerobic exercise is associated with oxidative stress and tissue damage in the body. There is indication that generation of oxygen free radicals and other reactive oxygen species may be the underlying mechanism for exercise-induced oxidative damage, but a causal relationship remains to be established. Enzymatic and nonenzymatic antioxidants play a vital role in protecting tissues from excessive oxidative damage during exercise. Depletion of each of the antioxidant systems increases the vulnerability of various tissues and cellular components to reactive oxygen species. Because acute strenuous exercise and chronic exercise training increase the consumption of various antioxidants, it is conceivable that dietary supplementation of specific antioxidants would be beneficial.     

磁场对酶学效应影响的研究进展

本文就近年来国内外关于脉冲磁场和恒定磁场对于生物体内各种酶的活性、构象、酶促反应动力学的效应的研究进行了综述。     

In vitro and in vivo studies on the antioxidant activity of fish peptide isolated from the croaker (Otolithes ruber) muscle protein hydrolysate

Peptide from croaker (Otolithes ruber) muscle protein hydrolysate was purified, characterized and evaluated for its in vitro and in vivo antioxidant activity. Results showed that purified peptide contained the amino acid sequence as Lys-Thr-Phe-Cys-Gly-Arg-His (861.6Da), which were expected to contribute to its antioxidant activities. This peptide efficiently quenched 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals (84.5±1.2 and 62.4±2.9%), and successfully inhibits the lipid peroxidation and DNA damage and proven to be a potent antioxidant at different in vitro systems. It also improved the endogenous cellular antioxidant enzymes in Wistar rat by increasing the activities of catalase (CAT), glutathione-S-transferase (GST) and superoxide dismutase (SOD) after supplementation of the peptide (283.6±7.25, 4.3±0.78 and 28.42±1.97) compared to the negative control (196.4±5.65, 1.3±0.45 and 15.1±0.35). Therefore, croaker muscle peptide can increase an endurance capacity and facilitate recovery from oxidative stress.     

Effect of Garlic Supplementation on Erythrocytes Antioxidant Parameters, Lipid Peroxidation, and Atherosclerotic Plaque Formation Process in Oxidized Oil-Fed Rabbits

Effect of garlic supplementation on blood antioxidant status, lipid peroxidation, and coronary plaque formation process was investigated in oxidized oil-fed rabbits. Eighteen adult male mixed European rabbits were given a balanced diet (21 g% protein, 34 g% fat, 45 g% carbohydrate), which contained isocaloristic addition of nonoxidized or oxidized rapeseed oil in the presence and absence of garlic. The experiment lasted 24 weeks. At the beginning and every 6 weeks, rabbits were weighed, and blood was taken. To evaluate the antioxidant status of the rabbits, erythrocytes malondialdehyde (MDA) concentration, total superoxide dismutase (t-SOD), and glutathione peroxidase (GPX) activations were determined. After the experiment was completed, aortas were dissected for histological examinations. Changes in the contents of the above parameters and histological examinations showed that oxidized rapeseed, oil administered to rabbits, caused the development of atherosclerotic changes and disturbed antioxidant status. The addition of garlic in such diets inhibited atherosclerotic changes in the aorta wall, and it is related to the homeostatic activity of antioxidative enzymes and lipid peroxidation.     

The Effect of Magnesium on Oxidative Neuronal Injury In Vitro

Abstract: The effect of magnesium on the oxidative neuronal injury induced by hemoglobin was assessed in murine cortical cell cultures. Exposure to 5 µ M hemoglobin in physiologic (1 m M ) magnesium for 26 h resulted in the death of about one-half the neurons and a sixfold increase in malondialdehyde production; glia were not injured. Increasing medium magnesium to 3 m M reduced neuronal death by about one-half and malondialdehyde production by about two-thirds; neuronal death and lipid peroxidation were approximately doubled in 0.3 m M magnesium. Comparable results were observed in spinal cord cultures. The NMDA antagonist MK-801 weakly attenuated hemoglobin neurotoxicity in low-magnesium medium, but tended to potentiate injury in physiologic magnesium. Incubation in low-magnesium medium alone for 24 h reduced cellular glutathione by ∼50% in mixed neuronal and glial cultures but by only 10% in pure glial cultures. The iron-dependent oxidation of phosphatidylethanolamine liposomes was attenuated in a concentration-dependent fashion by 2.5–10 m M magnesium; a similar effect was provided by 0.01–0.1 m M cobalt. However, oxidation was weakly enhanced by 0.5–1 m M magnesium. These results suggest that the vulnerability of neurons to iron-dependent oxidative injury is an inverse function of the extracellular magnesium concentration. At high concentrations, magnesium inhibits lipid peroxidation directly, perhaps by competing with iron for phospholipid binding sites. At low concentrations, enhancement of cell death may be due to the combined effect of increased NMDA receptor activity, glutathione depletion, and direct potentiation of lipid peroxidation.     

Interaction Between Polyamine and Nitric Oxide Signaling in Adaptive Responses to Drought in Cucumber

The effect of polyamines (PAs) on nitric oxide (NO) generation was investigated in cucumber (Cucumis sativus cv. Dar) primary leaves using bio-imaging with an NO-selective fluorophor, DAF-2DA. Seedlings pretreated with PAs and subjected to water deficit showed early (after 5 h) and transient NO production. The amplitude of the response depended on the form of the applied polyamine. Spermine (1.0 mM) and spermidine (1.0 mM) induced higher NO-dependent fluorescence compared with putrescine (1.0 mM) and the control. The NO production was blocked by tungstate, an inhibitor of nitrate reductase, and partially by an inhibitor of nitric oxide synthase (NOS-like) enzymes. NO donor administration preceding drought had no effect on endogenous PA levels but was positively correlated with an alleviation of water deficit-induced membrane permeability and lipid peroxidation. Application of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), a membrane-permeable NO scavenger, markedly reversed the NO donor effects. Similarly, pretreating seedlings with PAs resulted in lower ion leakage from the membrane and modified lipid peroxidation. The results indicate that NO may act downstream of PAs in cucumber seedlings under water stress.     

静磁场对小鼠黑色素瘤细胞B16生长和氧化应激的影响

目的:利用小鼠黑色素瘤细胞B16,研究静磁场对肿瘤细胞生长和氧化应激的影响,探讨氧化应激介导静磁场影响肿瘤细胞生长的机制,为磁场在肿瘤疾病的治疗中的应用提供理论依据。方法:采用MTT法测定磁场对B16细胞活力的影响;利用流式细胞仪测定静磁场暴露对B16细胞周期分布的影响;利用生物化学方法测定磁场暴露对细胞氧化防御系统相关蛋白酶活性的影响。结果:24 h内50 m T-200 m T静磁场暴露可以抑制B16生长,但超过24 h的磁场暴露可以促进B16生长;100 m T和200 m T静磁场暴露对B16的细胞周期分布没有影响;B16暴露于100 m T和200 m T静磁场48 h,GST活性和GSH/GSSG水平表现为先上升后下降,SOD活性和T-AOC水平先下降后上升,CAT活性没有受到影响。结论:50 m T-200 m T静磁场可以抑制小鼠黑色素瘤细胞B16的生长,诱导肿瘤细胞产生氧化应激。     

Effects of Exogenous Selenium on Nicotine-Induced Oxidative Stress in Rats

The effect of two different doses of selenium [1 and 50 μg selenium/100 g body weight (wt)] on nicotine-induced oxidative damage in liver was investigated in experimental rats. Male albino rats were maintained for 60 days as follows: (1) control group (normal diet), (2) nicotine group (0.6 mg/kg body wt)/day, (3) high-dose selenium (50 μg/100 g body wt)/day, (4) high-dose selenium (50 μg/100 g body wt) + nicotine (0.6 mg/kg body wt)/day, (5) low-dose selenium (1 μg/100 g body wt)/day, and (6) low-dose selenium (1 μg/100 g body wt) + nicotine (0.6 mg/kg body wt)/day. Nicotine administration caused a decrease in the activity of antioxidant enzymes, an increase in the concentration of lipid peroxidation products and protein carbonyls and an increase in the activity of nitric oxide synthase compared to the control group. Coadministration of nicotine and selenium reduced the concentration of lipid peroxidation products and increased the activity of antioxidant enzymes compared to the nicotine group. Selenium also enhanced the metabolism of nicotine. The antioxidant effect was more significant in the group administered a low dose of selenium.     

Effects of vanadate on male rat reproductive tract histology, oxidative stress markers and androgenic enzyme activities

Vanadium has been recognized as industrial hazards that adversely affect male reproductive systems of humans and animals. However, less information is available concerning the underlying mechanism in the pathogenesis of male reproductive dysfunction. The present study investigated the possible involvement of oxidative stress to induce oxidative deterioration of testicular functions in adult rats. The results of in vitro and in vivo studies demonstrate that vanadium treatment resulted in a significant dose- and time-dependent increase in the testicular lipid peroxidation, marked inhibition in the level of superoxide dismutase and catalase activities, decreased sperm counts, and substantially inhibited the activities of Delta(5)3beta- and 17beta-hydroxysteroid dehydrogenase as well as serum testosterone level. Histopathological examination revealed inhibition of spermatogenesis and the preferential loss of maturing and elongated spermatids along with increased percent of abnormal sperm. Taken together, the results suggest that an increase in free radical formation relative to loss of antioxidant defense system during vanadium exposure may render testis more susceptible to oxidative damage leading to their functional inactivation. Thus the toxic effects of vanadium are cumulative and that vanadium produced damages in testes are dose- and time-dependent.     

The Oxidative and Morphological Effects of High Concentration Chronic Toluene Exposure on Rat Sciatic Nerves

This study was designed to investigate the effects of chronic toluene inhalation in high concentration on lipid peroxidation, antioxidant enzyme activities and ultrastructural changes in the sciatic nerves of rats. Male Wistar albino rats (150–250 g) were divided in two experimental groups: the control and the toluene treated group (n=10 for each). Toluene treatment was performed by inhalation of 3000 ppm toluene, in a 8 h/day and 6 day/week order for 16 weeks. Blood and tissue samples were obtained for biochemical and histopathological investigation. The blood and sciatic nerves were assayed for toluene by gas chromatography. Toluene significantly increased blood and tissue malondialdehyde (MDA), and decreased tissue superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), but not tissue catalase (CAT) levels when compared with controls. Electron micrographs of sciatic nerve in the toluene group shows myelin destructions with onion-bulb and bubble form protrusion on the myelin sheath and axolemma border of myelinated axons. The area of injury on the myelin sheath were measured by Image-Pro Plus. Mean of the injury area were estimated 34% each myelin. These findings indicate that chronic toluene inhalation might be involved with free radical processes.     

Oxidative stress and antioxidant defense responses by goldfish tissues to acute change of temperature from 3 to 23 °C

The effects of a rapid transfer from a low (3 °C) to a warm (23 °C) temperature on oxidative stress markers and antioxidant defenses were studied in the brain, liver and kidney of the goldfish, Carassius auratus. Cold-acclimated fish were acutely moved to 23 °C and sampled after 1, 6, 12, 24, 48 or 120 h of warm temperature exposure. Lipid peroxide levels increased quickly during the first few hours at 23 °C, but thiobarbituric acid-reactive substances changed little. Protein carbonyl content was reduced by 20–40% in the liver over the entire experimental course, but increased transiently in the kidney. The content of high-molecular mass thiols decreased by two-thirds in the brain and was affected slightly in other organs. By contrast, total low-molecular mass thiols (e.g. glutathione and others) increased transiently. Activities of the primary antioxidant enzymes—superoxide dismutase and catalase—were generally unaffected in goldfish organs, whereas glutathione-dependent enzymes were elevated in the brain and kidney after 24–48 h at 23 °C. Glutathione peroxidase increased by 1.5–2.3-fold and glutathione-S-transferase by 1.7-fold. Hence, a short-term exposure to warm temperature disturbed several oxidative stress markers, but only slightly affected the activities of antioxidant enzymes. However, comparison of the current data for cold-acclimated winter fish with the same parameters in summer fish suggests that longer exposure to high ambient temperature requires the enhancement of activities of glutathione-dependent enzymes for maintaining the steady-state levels lipid peroxidation and protein oxidation in goldfish tissues.     

Oxidative stress and antioxidant status in patients with autoimmune liver diseases

Abstract

Objective

To estimate oxidative stress and antioxidant components during different stages of autoimmune liver diseases and assess their possible implication on disease progression.

Methods

We determined several markers of oxidative injury (isoprostane, aldehydes, protein carbonyls, 3-nitrotyrosine, and myeloperoxidase) and antioxidant components (glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase, and catalase) in whole blood, serum, and urine in 49 patients with autoimmune cholestatic liver diseases (AC) and 36 patients with autoimmune hepatitis (AIH) and healthy subjects matched for sex and age.

Results

Both AC and AIH patients had increased levels of all lipid and protein oxidative injury products and significantly decreased whole blood glutathione levels compared to controls. AIH patients had significantly higher levels of aldehydes and glutathione peroxidase activity and significantly lower protein carbonyl levels compared to AC patients. Protein carbonyl and isoprostane levels increased and glutathione levels decreased gradually with progression from mild fibrosis to severe fibrosis and cirrhosis in both AC and AIH patients. In addition, both cirrhotic AC and AIH patients had significantly higher protein carbonyls compared to non-cirrhotics.

Discussion

We provide novel findings in support of a major contribution of oxidant/antioxidant imbalance in the progression of liver injury in AC and AIH.     

Oxidative events in neuronal and glial cell-enriched fractions of rat cerebral cortex

The aim of this work was to investigate how neurons and glial cells separated from rat brain cortex respond to “in vitro” oxidative stress induced by incubation of the cellular fractions in the presence of prooxidant mixtures; in addition, the endogenous enzymatic antioxidant capacity of the purified fractions was investigated. Neuronal and glial cell-enriched fractions were obtained from rat cerebral cortex following passages of the tissue through meshes and centrifugations. The following parameters were evaluated: antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), and glucose-6-phosphate dehydrogenase (G6PDH); lipid peroxidation products (TBARS) prior to (basal) and after (iron-stimulated) incubation with a mixture of iron and ascorbic acid; intracellular production of reactive oxygen species (ROS) using a fluorescent probe, dichlorofluorescin-diacetate, in basal, iron-stimulated, and menadione stimulated conditions. SOD and GSHPx activities showed no significant changes between neurons and glia, whereas CAT and G6PDH activities were found to be significantly lower in glia than in neurons. TBARS levels were significantly lower in the glial fraction than in neurons, both in basal and iron-stimulated conditions. ROS production showed no differences between neurons and glia in both basal and menadione-stimulated conditions. Iron-stimulation produced a marked increase in ROS production, limited to the neuronal fraction, with the glial values being similar to the basal ones. Our conclusion is that glia and neurons isolated from rat cerebral cortex show a similar pattern of the most important antioxidant enzymes and of their basal ROS production, whereas glia is more resistant in “oxidative stress” conditions.     

Exposure Time Related Oxidative Action of Hyperbaric Oxygen in Rat Brain

Hyperbaric oxygen (HBO) is known to cause oxidative stress in several organs and tissues. Due to its high rate of blood flow and oxygen consumption, the brain is one of the most sensitive organs to this effect. The present study was performed to elucidate the relation of HBO exposure time to its oxidative effects in rats’ brain cortex tissue. For this purpose, 49 rats were randomly divided into five groups. Except the control group, study groups were subjected to three atmospheres HBO for 30, 60, 90, and 120 min. Their cerebral cortex layer was taken immediately after exposure and used for analysis. Thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and nitrate–nitrite (NO_X) levels were determined. TBARS and SOD levels were found to increase in a time-dependent manner. GSH-Px activity reflected an inconsistent course. NO_X levels were found to be increased only in the 120 min exposed group. The results of this study suggests that HBO induced oxidative effects are strongly related with exposure time.     

温度和紫外辐射胁迫对西藏飞蝗抗氧化系统的影响

为探讨西藏飞蝗(Locusta migratoria tibetensis Chen)对环境的适应机制,报道了温度和紫外辐射胁迫对西藏飞蝗抗氧化系统影响。以西藏飞蝗成虫为试材,研究5—20℃低温、30—45℃高温胁迫和紫外线辐射对其抗氧化酶活性和膜脂过氧化物丙二醛(MDA)含量的影响。在5—20℃低温胁迫下,成虫体壁和消化道超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性及丙二醛(MDA)含量分别随温度降低而升高;在30—35℃高温胁迫下,成虫SOD、POD和CAT活性分别随温度升高而升高,当温度超过35℃时,3种氧化酶活性均下降。长波紫外辐射(UV-A)和中波紫外辐射(UV-B)对处理后24h和72h成虫的SOD活性的影响大于可见光,在UV-A、UV-B和可见光3种光波长处理下,成虫的POD和CAT活性随光照时间的延长而增加,其中UV-B对两种酶活性影响大于UV-A和可见光,表现为UV-B处理组>UV-A处理组>可见光处理组;UV-A和UV-B处理能导致虫体体壁MDA含量明显升高,且对脂质过氧化的诱导存在时间效应;雌虫体壁、雌虫消化道、雄虫体壁和雄虫消化道的MDA含量分别在UV-B72h、UV-A72h、UV-A72h和UV-B72h达最大值0.72、0.88、0.66和0.94 nmol/g鲜重。在20—5℃低温胁迫下,西藏飞蝗成虫抗氧化酶活性升高,能较好的保护自身免遭活性氧自由基的伤害;西藏飞蝗对高温忍耐力差,在高于35℃高温胁迫下,成虫SOD、POD、CAT活性均下降;在长波和中波紫外辐射下,西藏飞蝗抗氧化酶活性显著升高,是西藏飞蝗对紫外线辐射强度大的青藏高原的一种重要适应。     

Evaluation of used Purslane extracts in Tris extenders on cryopreserved goat sperm

This study aimed to evaluate the comparative effects of Purslane aqueous extract (PAE), Purslane methanolic extract (PME) and Purslane ethanolic extract (PEE on the quality of frozen-thawed goat spermatozoa. Collected semen with motility >75% and sperm concentration >1.0 × 10⁹ sperm/ml was pooled and divided into 10 equal aliquots and supplemented by basic extender containing 25, 50 or 100 μg/ml of Purslane aqueous extract (PAE_25μg/ml, PAE_50μg/ml, PAE_100μg/ml, respectively), basic extender containing 25, 50 or 100 μg/ml of Purslane methanolic extract (PME_25μg/ml, PME_50μg/ml, PME_100μg/ml, respectively), basic extender containing 25, 50 or 100 μg/ml of Purslane ethanolic extract (PEE_25μg/ml, PEE_50μg/ml, PEE_100μg/ml, respectively). Control diluent contained no additives. For the determination of sperm quality, frozen straws were thawed and then the sperm characteristics were assessed. Results indicated that higher (P < 0.05) percentages of total motility, viability, mitochondrial activity and lower percentages of malondialdehyde (MDA) for PAE_50μg/ml, PME_50μg/ml and PEE_50μg/ml than those of the control. In addition, PME_50μg/ml resulted in the highest) P < 0.05) total motility and the lowest (P < 0.05) MDA levels compared to other treatments. Compared to the control group, PME_50μg/ml resulted in higher integrity (P < 0.05) of plasma membranes and in lower amounts of apoptotic and dead spermatozoa. PME_50μg/ml and PAE_50μg/ml showed higher (P < 0.05) percentages of progressive motility, DNA integrity and live post-thawed spermatozoa than those of the control. No significant differences in the motility, viability, mitochondrial activity and number of live sperms were observed between PME_50μg/ml and PAE_50μg/ml treatments. In conclusion, the results of this study indicated that 50 μg/ml purslane extracts could be used for the cryopreservation. However, the results of methanolic extract was more beneficial compared to other extracts.     

Evaluation of the Antioxidant Properties of Propofol and its Nitrosoderivative. Comparison with Homologue Substituted Phenols

Propofol (2,6-diisopropylphenol), some substituted phenols (2,6-dimethylphenol and 2,6-ditertbutylphenol) and their 4-nitrosoderivatives have been compared for their scavenging ability towards 1,1-diphenyl-2-picrylhydrazyl and for their inhibitory action on lipid peroxidation. These products were also compared to the classical antioxidants butylated hydroxytoluene and butylated hydroxyanisole. When measuring the reactivity of the various phenolic derivatives with 1,1-diphenyl-2-picrylhydrazyl the following order of effectiveness was observed: butylated hydroxyanisole>propofol>2,6-dimethylphenol>2,6-di-tertbutylphenol?>?butylated hydroxytoluene. In cumene hydroperoxide-dependent microsomal lipid peroxidation, propofol acts as the most effective antioxidant, while butylated hydroxyanisole, 2,6-di-tertbutylphenol and butylated hydroxytoluene exhibit a rather similar effect, although lower than propofol. In the iron/ascorbate-dependent lipid peroxidation propofol, at concentrations higher than 10?μM, exhibits antioxidant properties comparable to those of butylated hydroxytoluene and butylated hydroxyanisole. 2,6-Dimethylphenol is scarcely effective in both lipoperoxidative systems. The antioxidant properties of the various molecules depend on their hydrophobic characteristics and on the steric and electronic effects of their substituents. However, the introduction of the nitroso group in the 4-position almost completely removes the antioxidant properties of the examined compounds. The nitrosation of the aromatic ring of antioxidant molecules and the consequent loss of antioxidant capacity can be considered a condition potentially occurring in vivo since nitric oxide and its derivatives are continuously formed in biological systems.     

The in vitro effect of temperature on motility and antioxidant response of common carp Cyprinus carpio spermatozoa

The effect of temperature on Cyprinus carpio spermatozoa in vitro was investigated with spermatozoa activated at 4, 14, and 24 °C. At 30 s post-activation, motility rate was significantly higher at 4 °C compared to 14 and 24 °C, whereas highest swimming velocity was observed at 14 °C. The thiobarbituric acid-reactive substance (TBARS) content was significantly higher at 14 °C and 24 °C than at 4 °C in motile spermatozoa. No significant differences in catalase and superoxide dismutase activity relative to temperature were observed. This study provides new information regarding effect of temperature on lipid peroxidation intensity and spermatozoon motility parameters in carp. The elevation of TBARS seen at higher temperatures could be due to inadequate capacity of antioxidant enzymes to protect the cell against the detrimental effects of oxidative stress induced by higher temperatures.     

Alterations of Antioxidant Enzymes and Oxidative Damage to Macromolecules in Different Organs of Rats During Aging

Oxygen free radicals have been hypothesized to play an important role in the aging process. To investigate the correlation between the oxidative stress and aging, we have determined the levels of oxidative protein damage and lipid peroxidation in the brain and liver, and activities of antioxidant enzymes in the brain, liver, heart, kidney, and serum from the Fisher 344 rats at ages of 1, 6, 12, 18, and 24 months. The results showed that the level of oxidative protein damage (measured as carbonyl content) in the brain and liver was significantly higher in older animals than in young animals. No statistical difference was observed in the lipid peroxidation of the liver and brain between young and old animals. The activities of antioxidant enzymes in most tissues displayed an age-dependent decline. Superoxide dismutases in the heart, kidney, and serum, glutathione peroxidase activities in the serum and kidney, and catalase activities in the brain, liver, and kidney, significantly decreased during aging. Cytochrome c oxidase, an enzyme involved in electron transport in mitochondria, initially increased, but subsequently decreased in the aged brain, whereas no significant alteration was observed in the liver mitochondrial antioxidant enzymes. The present studies suggest that the accumulation of oxidized proteins during aging is most likely to be linked with an age-related decline of antioxidant enzyme activities, whereas lipid peroxidation is less sensitive to predict the aging process.