Effect of dioxydine and cyclophosphane on lipid peroxidation and superoxide dismutase and catalase activities in C57Bl/6 and BALB/c mice

Twenty-four hours after intraperitoneal injection of cyclophosphane (40 mg/kg) and dioxydine (300 mg/kg) to C57Bl/6 mice, liver catalase activity dropped by 29 and 23%, respectively. In BALB/c mice, dioxydine (but not cyclophosphane) reduced catalase activity by 24%. Superoxide dismutase activity was lowered by cyclophosphane (but not dioxydine) in BALB/c mice, and by both dioxydine and cyclophosphane in C57Bl/6 mice (by 24 and 86%, respectively). The level of 2-thiobarbituric acid (TBA)-reactive lipid peroxidation (LPO) products in the liver of BALB/c mice treated with cyclophosphane and dioxydine increased 1.4- and 2.1-fold, respectively, while in C57Bl/6 mice it did not differ from the control. The initial rate ofin vitro-induced LPO in BALB/c mice receiving cyclophosphane and dioxydine increased 1.5- and 4-fold, respectively. In C57Bl/6 mice both cyclophosphane and dioxydine inhibited the accumulation of TBA-reactive LPO products. On the whole, animals of the C57Bl/6 strain are more resistant to the LPO-inducing action of mutagens than BALB/c mice, despite the fact that the latter are characterized by a higher activity of antioxidant enzymes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, No. 5, pp. 528–532, May, 1996     

Imbalance in the antioxidant defense system as a possible cause of decreased compensatory and adaptive reserves in youths with mitral valve prolapse

An imbalance in the first line of the antioxidant defence and hyperactivity of the glutathione-dependent system were revealed in 137 youths with mitral valve prolapse. Increased activities of superoxide dismutase and glutathione reductase (by 6 and 1.82–2.10 times, respectively) can serve as an additional diagnostic criterion of decreased compensatory reserves in patients with mitral valve prolapse. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 5, pp. 519–521, May, 2007     

Pyruvate slows disease progression in a G93A SOD1 mutant transgenic mouse model

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease caused by selective motor neuron death, and currently no effective treatment is available for ALS. In this study, we investigated the neuroprotective effects of pyruvate, which acts as an anti-oxidant and as an energy source. We treated G93A SOD1 transgenic mice with pyruvate (from 70 days of age, i.p., at 1000 mg/kg/week), and found that it prolonged average lifespan by 12.3 days (10.5%), slowed disease progression, and improved motor performance, but did not delay disease onset. Pyruvate treatment was also associated with reduced nitrotyrosine immunoreactivity, gliosis, and increased Bcl-2 expression in the spinal cords of G93A SOD1 transgenic mice. These results suggest that pyruvate treatment may be a potential therapeutic strategy in ALS.     

Preventing HIV-1 Tat-induced neuronal apoptosis using antioxidant enzymes: mechanistic and therapeutic implications

HIV-1 proteins, especially gp120 and Tat, elicit reactive oxygen species (ROS) and cause neuron apoptosis. We used antioxidant enzymes, Cu/Zn superoxide dismutase (SOD1) and glutathione peroxidase (GPx1) to study signaling and neuroprotection from Tat-induced apoptosis. SOD1 converts superoxide to peroxide; GPx1 converts peroxide to water. Primary human neurons were transduced with SV40-derived vectors carrying SOD1 and GPx1, then HIV-1 Tat protein was added. Both SV(SOD1) and SV(GPx1) delivered substantial transgene expression. Tat decreased endogenous cellular, but not transduced, SOD1 and GPx1. Tat rapidly increased neuron [Ca(2+)](i), which effect was not altered by SV(SOD1) or SV(GPx1). However, both vectors together blocked Tat-induced [Ca(2+)](i) fluxes. Similarly, neither SV(SOD1) nor SV(GPx1) protected neurons from Tat-induced apoptosis, but both vectors together did. Tat therefore activates multiple signaling pathways, in one of which superoxide acts as an intermediate while the other utilizes peroxide. Gene delivery to protect neurons from Tat must therefore target both.     

Superoxide dismutases of heavy metal resistant streptomycetes

Heavy metal tolerant and resistant strains of streptomycetes isolated from a former uranium mining site were screened for their superoxide dismutase expression. From the strains tolerating high concentrations of different heavy metals, one was selected for its tolerance of concentrations of heavy metals (Ni, Cu, Cd, Cr, Mn, Zn, Fe). This strain, Streptomyces acidiscabies E13, was chosen for the purpose of superoxide dismutase analysis. Gel electrophoresis and activity staining revealed only one each of a nickel (NiSOD) and an iron (FeZnSOD) containing superoxide dismutase as shown by differential enzymatic repression studies. The gene for nickel containing superoxide dismutase, sodN, was cloned and sequenced from this strain. The genomic sequence shows 92.7% nucleotide identity and 96.1% amino acid identity to sodN of S. coelicolor. Expression can be activated by nickel as well as other heavy metals and active enzyme is produced in media lacking nickel but containing copper, iron or zinc. Thus, the selected strain is well suited for further characterization of the enzyme encoded by sodN.     

肾病综合征患者红细胞免疫功能与脂质过氧化关系的探讨

目的：探讨了肾病综合征患者红细胞免疫功能与脂质过氧化的关系。方法：应用红细胞酵母花环法测定了31例肾病综合征患者的红细胞免疫功能和化学法测定血清丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-PX）含量,并与35名正常健康人作比较。结果：肾病综合征患者RBC-ICR花环率和MDA水平明显升高（P〈0.01）,而RBC-C3bR,SOD,GSH-PX水平则〈正常（P〈0.01）,相关分析显示：RBC-C3b花环与MDA呈显著负相关（r=-0.4786,P〈0.01）,RBC-ICR与MDA呈正相关（r=0.6702,P〈0.01）。结论：肾病综合征患者红细胞免疫黏附功能的降低与活性代谢紊乱密切相关。     

慢性肾炎患者血浆leptin和血清IL-6、EL-18及SOD检测的临床意义

目的：探讨慢性肾炎患者治疗前后血浆leptin和血清IL-6、IL．18及SOD水平的变化及临床意义。方法：应用放射免疫分析和酶联免疫法对33例慢性肾炎患者进行了血浆leptin和血清IL-6、IL．18及SOD检测,并与35名正常健康人作比较。结果：慢性肾炎患者在治疗前血浆leptin和血清IL-6、IL．18均显着地高于正常人组（P〈0．01）,而血清SOD水平则显着地低于正常人组（P〈0．01）。经中西医结合治疗3个月后与正常人组比较仍有显著性差异（P〈0．05）,血浆leptin水平与血清IL-6、IL．18水平呈正相关（r=0．5718、0．4916,P〈0．01）,而与SOD水平呈负相关（r=-0．6018,P〈0．01）。结论：检测慢性肾炎患者治疗前后血浆leptin和血清IL-6、IL-18及SOD水平的变化对临床观察和预后有重要的临床价值。     

Respiratory long-term facilitation following intermittent hypoxia requires reactive oxygen species formation

Acute intermittent hypoxia (AIH) elicits a form of respiratory plasticity known as long-term facilitation (LTF). LTF is a progressive and sustained increase in respiratory motor output as expressed in phrenic and hypoglossal (XII) nerve activity. Since reactive oxygen species (ROS) play important roles in several forms of neuroplasticity, and ROS production is increased by intermittent hypoxia, we tested the hypothesis that ROS are necessary for phrenic and XII LTF following AIH. Urethane-anesthetized, paralyzed, vagotomized and pump-ventilated Sprague-Dawley rats were exposed to AIH (11% O2, 3, 5 min episodes, 5 min intervals), and both phrenic and XII nerve activity were monitored for 60 min post-AIH. Although phrenic and XII LTF were observed in control rats, i.v. manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride (MnTMPyP), a superoxide anion scavenger, attenuated both phrenic and XII LTF in a dose dependent manner. Localized application of MnTMPyP (5.5 mM; 10 microl) to the intrathecal space of the cervical spinal cord (C4) abolished phrenic, but not XII LTF. Thus, ROS are necessary for AIH-induced respiratory LTF, and the relevant ROS appear to be localized near respiratory motor nuclei since cervical MnTMPyP injections impaired phrenic (and not XII) LTF. Phrenic LTF is a novel form of ROS-dependent neuroplasticity since its ROS-dependence resides in the spinal cord.     

Exogenous reactive oxygen and nitric oxide alter intracellular oxidant status of skeletal muscle fibres

To test whether exogenous oxidants alter intracellular oxidant levels in skeletal muscle fibres, we exposed rat diaphragm to donors of nitric oxide (NO_x), reactive oxygen species (ROS) or hyperoxia, and monitored intracellular oxidant levels using a fluorescent probe. Fibre bundles were dissected from the diaphragm and loaded with 2’,7’-dichlorodihydrofluorescein (DCFH); emissions were monitored using a fluorescence microscope. DCFH-loaded muscles were exposed to either a NO_x donor (1 m M S-nitroso-N-acetyl penicillamine, SNAP; 1 m M sodium nitroprusside, SNP; 400 μM 1-hydroxy-2-oxo-3-(N-3-methyl-aminopropyl)-3-methyl-1-triazen, NOC-7), an ROS donor (100 μM hydrogen peroxide, H₂O₂; 100 μM tert-butyl hydroperoxide; 1 m M hypoxanthine plus 0.01 U mL^–1 xanthine oxidase, HXXO) or a range of PO ₂s (25, 60 or 95% O₂ oxygenating Krebs–Ringer solution) for 40 min; time-matched control bundles remained in Krebs–Ringer solution. Control muscles oxidized DCFH at a rate of 0.32 ± 0.1 greyscale units min^–1. SNAP (766%), SNP (1244%), NOC-7 (851%), H₂O₂ (543%), and HXXO (541%) increased DCFH oxidation from control levels. The increase in emissions caused by NOC-7 and SNP were blunted by the NO_x scavenger haemoglobin (1 μM ). DCFH oxidation by HXXO was unaffected by 1000 U mL^–1 superoxide dismutase but was significantly decreased by 1000 U mL^–1 catalase and 1 m M salicylate. PO ₂ had no effect on intracellular oxidant levels. Therefore, extracellular NO_x and ROS can alter intracellular oxidant status in skeletal muscle fibres. These observations suggest that intrafibre oxidant levels could be the result of both intracellular and extracellular oxidant production.     

神经再生复合剂对大鼠急性脊髓损伤后其内MDA、SOD和MPO表达的影响

目的:观察促神经再生因子复合剂N6对大鼠急性脊髓损伤后脊髓及血清丙二醛(MDA)、超氧化物歧化酶(SOD)及脊髓内髓过氧化物酶(MPO)表达的影响,探讨其减轻继发性损伤的作用机制及保护受损脊髓作用的最佳介入时间。方法:用改良Allen’s打击法制备大鼠急性脊髓损伤模型,假手术组打开椎板不损伤脊髓,模型组造模后不予治疗,对照组分别于脊髓损伤后10、30和60 min向腹腔注射甲级强的松龙(30 mg/kg),实验组分别于脊髓损伤后10、30和60 min向蛛网膜下腔注射促神经再生因子复合剂N6(166μg/kg)。造模后24 h取材,于各时间点测得假手术组、模型组、实验组和对照组大鼠脊髓损伤组织及血清中MDA、SOD及损伤脊髓组织的MPO活性。结果:实验组损伤脊髓组织MDA含量随着药物介入时间的延迟而增高,各时间点间MDA含量无显著性差异(P>0.05);血清MDA含量随着药物介入时间的延迟而增高,60 min与10、30 min相比有显著性差异(P<0.05);实验组损伤脊髓组织SOD含量随着药物介入时间的延迟而降低,各时间点间SOD含量无显著性差异(P>0.05);血清SOD含量随着药物介入时间的延迟而降低,60 min与10 min相比有显著性差异(P<0.05);实验组损伤脊髓组织MPO含量随着药物介入时间的延迟而增高,60 min与10 min相比有显著性差异(P<0.05)。结论:促神经再生因子复合剂N6治疗可以提高急性脊髓损伤大鼠损伤脊髓及血清SOD含量,降低损伤脊髓及血清MDA、损伤脊髓MPO的含量,从而降低急性脊髓损伤后的继发性损伤,达到保护脊髓组织的目的,且介入治疗时间越早,疗效越好。