Blockade of superoxide generation prevents high-affinity immunoglobulin E receptor-mediated release of allergic mediators by rat mast cell line and human basophils

BACKGROUND: Previous studies have shown that rat peritoneal mast cells and mast cell model rat basophilic leukaemia (RBL-2H3) cells generate intracellular reactive oxygen species (ROS) in response to antigen challenge. However, the physiological significance of the burst of ROS is poorly understood. OBJECTIVE: The present study was undertaken to investigate the role of superoxide anion in mediator release in rat and human cell systems. METHODS: RBL-2H3 cells were directly stimulated with anti-rat FcepsilonRI alpha-subunit monoclonal antibody (mAb). For the analysis of human cell system, leucocytes were isolated by dextran sedimentation from healthy volunteers or from patients, and challenged either with anti-human FcepsilonRI mAb or with the relevant antigens. Superoxide generation was determined by chemiluminescence-based methods. The releases of histamine and leukotrienes (LT)s were determined by enzyme-linked immunosorben assay (ELISA). RESULTS: Cross-linking of FcepsilonRI on RBL-2H3 cells or on human leucocytes from healthy donors by the anti-FcepsilonRI mAb resulted in a rapid generation of superoxide anion, as determined by chemiluminescence using superoxide-specific probes. Similarly, leucocytes from patients generated superoxide anion in response to the challenge with the relevant allergen but not with the irrelevant allergen. Furthermore, diphenyleneiodonium (DPI), a well-known inhibitor of flavoenzymes suppressed the superoxide generation and the release of histamine and LTC4 induced by the anti-FcepsilonRI mAb or by allergen in parallel. CONCLUSION: These results indicate that both RBL-2H3 cells and human basophils generate superoxide anion upon FcepsilonRI cross-linking either by antibody or by allergen challenge and that blockade of the generation prevents the release of allergic mediators. The findings strongly support the role of superoxide generation in the activation of mast cells and basophils under both physiological and pathological conditions. The findings suggest that drugs regulating the superoxide generation have potential therapeutic use for allergic disorders.     

Effects of Activated Complement on Lung Fluid Exchange in Conscious Goats:Role of Superoxide Anion

The effects of zymosan-activated plasma(ZAP)on lung fluid exchangeand on superoxide anion production by granulocytes were studied in 8 consciousgoats with chronic lung lymph fistula,It was found that after ZAP infusion, thecirculating granulocytes were activated and the release of superoxide anions wasmarkedly enhanced. There was an increase in lung lymph flow and proteinconcentration.It suggests that the superoxide anion released by the stimulatedgranulocytes can play a role in inducing lung injury by the activated complement.     

Additive effects of earthworm extract with HpD-laser on the enhancement of reactive oxygen production and the inhibition of[~3H]—thymidine.uptake in mouse ascitic tumor cells

The effects of combined use of earthworm extract(912)and HpD-laser on the produc-tion of reactive oxygen and the biosynthesis of DNA in S_(180) tumor cells were studied throughchemiluminescence measurement and[~3H]-TdR incorporation assay.The results showed that as com-pared with the control,the intensity of chemiluminescence emitted by tumor cells treatedsimultaneously with 912 and HpD-laser was enhanced more than ten-folds,while that treated with912 or HpD-laser alone was increased only 2～4 folds.The[~3H]-TdR incorporation into tumorcells of the former group was inhibited upto 74.1%,and that of the latter groups decreased onlyby 42.2% and 40.0%,respectively.In accordance with these biochemical changes,the ultrastructuraldamage of tumor cells of the former,combinedly treated group appeared to be the most serious.This suggests an additive effect of 912 with HpD-laser on tumor cells.In addition,if free radicalscavengers,such as catalase and superoxide dismutase,were added to the reaction systembefore chemiluminescence assay,the luminescent enhancement effect mentioned above was dramaticallyalleviated,implying the presence of O_2~ and H_2O_2 in the system.Therefore,as to the toxic effecton tumor cells,912 and HpD-laser are not only additive in efficiency,but also similar in theunderlying mechanism of action.     

亚硝酸盐法测定超氧化物歧化酶活性

用亚硝酸盐、氰化钾抑制区别法测定样品中的 Cu,Zn-SOD 和 Mn-SOD,灵敏度高,重现性好,操作简便。实验表明,抑制率达50%时所需 SOD 的浓度为0.07 μg/ml,其批内和批间的变异系数分别为6.0%和5.5%,鸡肝 Cu,Zn-SOD 与 KCN 的抑制复合物的表观解离常数 K′为288.6±45.5 μmol。     

Polymorphisms in manganese superoxide dismutase and catalase genes: functional study in Hong Kong Chinese asthma patients

BACKGROUND: Reactive oxygen species may contribute to the pathogenesis of asthma. Functional genetic polymorphisms of antioxidant enzymes, superoxide dismutase (SOD) and catalase are good candidates for asthma susceptibility. OBJECTIVE: To investigate the association of the manganese-containing form of SOD (MnSOD) gene at amino acid position 16 (Val16Ala) and catalase gene in the promoter at A-21T and C-262T polymorphisms and asthma in a Hong Kong Chinese population. METHODS: The association study was conducted in a case-control design in asthma patients (n=251) and healthy controls (n=316) by genotyping. The functional significance was assessed by determining erythrocyte SOD and catalase activity. RESULTS: The Val allele of MnSOD at Val16Ala and the A allele of catalase gene at A-21T were not different between patients and controls, while the C allele of catalase gene at C-262T was found to be significantly different between patients and controls (P=0.033). The less frequent variant of catalase gene (-262T) was found to be protective from the development of asthma in a Hong Kong Chinese non-smoking population (adjusted odds ratio=0.35, 0.15-0.85; P=0.017). Asthma patients had elevated erythrocyte SOD and catalase activities in comparison with healthy controls (P<0.01). However, their activities were not associated with different genotypes within healthy controls or asthma patients. CONCLUSION: This is the first report showing that SOD and catalase functional activities are not associated with their respective genetic polymorphisms but related to the presence of asthma in a Hong Kong Chinese population.     

人参二醇组皂甙对精索静脉曲张大鼠的保护作用及其机制

把56只成年Wistar大鼠分为如下3组:①精索静脉曲张组(VG)30只;②精索静脉曲张人参二醇组皂甙组(VPG)8只;③假手术组(SOG)18只。实验结果表明,人参二醇组皂甙可显著提高精索静脉曲张大鼠睾丸ACE活力并降低睾丸LPO含量,但3组动物睾丸的SOD水平无明显差异。作者认为人参二醇组皂甙可能是通过减少LPO产生以提高ACE活力,从而实现对精索静脉曲张大鼠的保护作用。     

猕猴桃中药复方制剂对血清SOD及MDA含量的影响

猕猴桃中药复方制剂系采用猕猴桃汁为基质，配加绞股蓝、丹参等中药的有效成分制成。为了研究它的保健作用，在６３例５０岁以上、无急性疾病的中、老年人，３６例３０～４９岁健康的青年，３２例１４～１７岁健康的少年中进行试验，１０ｍｌ每日２次连续服用３０天后，中老年人血液ＳＯＤ显著增高，７０岁以上老人平均增高２．８倍，血清ＭＤＡ明显下降，７０岁以上平均下降８７．５％。     

Pathogenesis of progressive muscular dystrophy: studies on free radical metabolism in an animal model

Evidence to suggest the presence of abnormal metabolism of oxygen free radicals in progressive muscular dystrophy is presented using an animal model. In the superficial pectoral muscles of dystrophic chickens, enzyme activities regulating the metabolism of oxygen free radicals, i.e., catalase, superoxide dismutases and glutathione peroxidase, were significantly elevated within 1 week of hatching. Activities of related enzymes, i.e., glutathione reductase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase were also elevated. In contrast, the specific activity of phosphofructokinase, the rate-limiting enzyme of the glycolytic pathway, was normal during the first 4-week period. These results suggest that there is an increased turnover of oxygen free radicals in the dystrophic muscle. This concept appears important in a further investigation of the pathogenesis and treatment of progressive muscular dystrophies.     

松花粉抗衰老作用的实验研究

目的　观察松花粉的抗衰老作用。方法　用含松花粉的饲料喂养衰老小鼠 ,测定小鼠血清中超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)、谷胱甘肽过氧化物酶 (GSH Per)的活性 ,测定脑组织中丙二醛 (MDA)含量及脑组织和肝脏中的脂褐质 (Lf)含量 ,同时测定胸腺和脾脏的重量及网状内皮系统的吞噬功能。结果　松花粉能明显增加衰老小鼠血清中SOD、CAT、GSH Per活性 ,降低脑组织中MDA含量及脑组织和肝脏中的Lf含量 ,并增加胸腺和脾脏质量 ,提高网状内皮系统吞噬功能。结论　松花粉具有抗衰老作用     

虾青素对成骨细胞羟自由基氧化损伤的影响

目的：在H2O2胁迫下，研究虾青素增强成骨细胞抗自由基损伤的作用。方法：用H2O2作用MC3T3-E1成骨细胞，建立自由基损伤细胞模型。培养的成骨细胞分为对照组、模型组、虾青素低剂量组（1×10^-7mol／L）、虾青素中剂量组（1×10^-6mol／L）和虾青素高剂量组（1×10^-5mol／L）。测定不同处理组细胞活力、超氧化物歧化酶（superoxide dismutase，SOD）活性、活性自由氧（reactive oxygen species，ROS）含量、脂质过氧化物（lipid oxygen，IJP0）含量，同时利用荧光偏振法测定细胞膜流动性。结果：模型组细胞活力、SOD活性、细胞膜流动性均比各剂量虾青素组显著降低（P〈0．01），而ROS、LPO含量均比各剂量虾青素组显著升高（P〈0．01）。结论：H2O2摄入会导致大鼠成骨细胞的氧化损伤，而虾青素可以预防或降低此类损伤对细胞的影响。