Age-related effects of oxidative metabolism and cyclic AMP signaling on neutrophil apoptosis

Spontaneous as well as Fas-induced polymorphonuclear cell apoptosis is unchanged in the elderly. However, a weak responsiveness to antiapoptotic signals elicited by proinflammatory molecules has been reported in neutrophils isolated from aged humans. To gain insight into this field, here we have evaluated the role of oxidative metabolism and cyclic AMP (cAMP) signaling on age-related neutrophil apoptotic cell death. Results show that although superoxide dismutase (SOD), added exogenously to cell cultures, is able to prolong neutrophil survival in both young and aged individuals, high amounts of the enzyme are further effective in cell cultures of young donors only. Notably, the addition of catalase gives rise to a more striking, yet comparable, inhibition of neutrophil-programmed cell death in both groups of subjects. Furthermore, even low amounts of catalase are enough to restore a normal apoptotic outcome in SOD-treated cell cultures of old donors. Unlike the oxidative metabolism, cAMP signaling activation does not reveal any difference in the apoptotic response of neutrophils isolated from young and aged donors. Thus, supplementation of cell cultures with prostaglandin E2, dibutyryl cAMP or, to a lesser degree, forskolin results in a dose-dependent inhibition of DNA cleavage product appearance in both groups of subjects. The data outline that an impairment of neutrophil antioxidant shield, leading to an augmented cell oxidative load, is likely to occur as a feature of age. This may increase the apoptotic rate of stimulated cells, which may in turn account for the increased susceptibility of elderly individuals to life-threatening infections.     

The effect of exhaustive exercise on the antioxidant enzyme system in skeletal muscle from calcium-deficient rats

 The aim of the current study was to elucidate the synergism of dietary calcium restriction and exhaustive exercise in the antioxidant enzyme system of rat soleus muscle, and to investigate the involvement of neutrophils in exercise-induced muscle damage. Forty-eight male Wistar rats were assigned to the following groups: control (C) or calcium-restricted [1 month (1 M) or 3 months (3 M)]. Each group was subdivided into acutely exercised or non-exercised groups. Soleus muscle from each rat was analysed to determine the levels of antioxidant enzymes [Mn-superoxide dismutase (SOD), Cu,Zn-SOD, glutathione peroxidase (GPX), and catalase (CAT)]. Dietary calcium restriction resulted in calcium deficiency and upregulated the antioxidant enzymes examined except GPX. Conversely, exhaustive exercise significantly decreased GPX and CAT, but not SODs activities in the calcium-restricted (1 M and/or 3 M) rats. Contents of immunoreactive Mn-SOD and Cu,Zn-SOD were only increased in the 3 M rats. During calcium restriction, the mRNA expression of both forms of SOD showed initial upregulation, followed by downregulation. Exhaustive exercise significantly increased the mRNA expressions only in the 3 M rats. Moreover, exhaustive exercise markedly increased myeloperoxidase activity in soleus muscles from the 1 M and 3 M rats compared with the C rats, and significantly enhanced the ability of neutrophils to generate superoxide in the 3 M rats. The results demonstrate that dietary calcium restriction upregulates certain antioxidant enzyme activities in rat soleus muscle, indicating an enhanced resistance to potential increases in intracellular reactive oxygen species. The results also suggest that exhaustive exercise may cause oxidative damage in soleus muscle of calcium-deficient rats through the activation of neutrophils. Received: 4 August 1997 / Received after revision: 29 September 1997 / Accepted: 26 November 1997     

冠心病患者治疗前后血清SOD、ET及T淋巴细胞亚群水平

目的:探讨了冠心病患者治疗前后血清SOD、ET及T淋巴细胞亚群水平。方法:分别应用放免法和单克隆抗体法对42例冠心病患者进行了血清SOD、ET及T淋巴细胞亚群水平检测,并与35名正常健康人作比较。结果:冠心病患者在治疗前血清ET水平显著地高于正常人组(P<0.01),而SOD和CD4/CD8比值明显地低于正常人组(P<0.01),经治疗后一个月则与正常人组比较差异无显著性(P>0.05)。结论:检测冠心病患者血清SOD、ET及T淋巴细胞亚群水平对判断病情及其预后均具有一定的临床实用价值。     

2-Mercapto-ethanol enhancement of agglutination reaction--a possible in vitro serological correlate for assessment of functional immunity in simian malaria

Conventional indirect haemagglutination test was performed in rhesus monkey sera (collected from Plasmodium knowlesi infected animals) with and without prior treatment of sera with 2-mercapto-ethanol (2-ME). Surprisingly, many sera samples showed significant enhancement of final titre with 2-ME. The 2-ME enhancement effect was more pronounced in the sera of hyperimmune monkeys on further injection of antigen or parasites. It was also noticeable in the sera during primary drug-suppressed P. knowlesi infection and appeared to have a bearing on the immune status of the animals to rechallenge. The use of a soluble antigen prepared from P. knowlesi infected erythrocytes was found to be essential in IHA test to demonstrate the 2-ME enhancement effect. Antigen prepared from freed parasites (commonly used) failed to show a similar effect in IHA. The possible role of certain T-lymphocyte products - antigen binding, non-agglutinating, 2-ME sensitive molecules - in malarial immunology has been proposed.     

内毒素休克时自由基对肝脏细胞和亚细胞器的损伤

本文探讨氧衍生的自由基在内毒素休克时对肝脏细胞和亚细胞的损伤作用。给大鼠静注内毒素(3mg/kg体重)0.5小时后,尽管肝组织MDA没有明显升高(P>0.05),但线粒体和溶酶体悬液中MDA以及肝组织、线粒体、溶酶体SOD较对照已明显升高(P<0.05)。休克后2小时,肝组织、线粒体、溶酶体MDA均显著升高(P<0.01～0.001),以后升高更甚(P<0.001)。线粒体、溶酶体SOD在休克后2小时明显下降(P<0.05),休克后4小时肝组织和亚细胞器SOD均明显受抑(P<0.01～0.001)。血浆,溶血液MDA、SOD和溶酶体酶在休克后均有程度不同的改变。实验结果表明氧衍生的自由基在内毒素休克时引起肝细胞和线粒体、溶酶体等亚细胞器的脂质过氧化损伤,而亚细胞器的损伤似乎早于组织损伤。     

金雀异黄酮对去卵巢大鼠脑抗氧化作用的影响

目的研究金雀异黄酮对去卵巢大鼠大脑抗氧化作用的影响,为使用植物雌激素防治女性更年期后老年性痴呆提供依据。方法40只3月龄雌性SD大鼠,随机分为假手术组、去卵巢对照组、金雀异黄酮组和苯甲酸雌二醇组,给予相应手术和治疗。术后6周分析大鼠额叶、颞叶、海马和基底前脑的SOD和MDA值。结果假手术组颞叶和海马的SOD值低于基底前脑(P<0.05);额叶和颞叶的MDA值高于海马和基底前脑(P<0.05);去卵巢对照组基底前脑的SOD值显著低于假手术组、金雀异黄酮组和苯甲酸雌二醇组(P<0.05),MDA值显著高于假手术组、金雀异黄酮组和苯甲酸雌二醇组(P<0.05);假手术组、金雀异黄酮组及苯甲酸雌二醇组之间SOD值和MDA值差异无统计学意义(P>0.05)。结论去卵巢对照组大鼠基底前脑抗氧化能力显著降低,氧化损伤程度显著升高,金雀异黄酮替代治疗可增加去卵巢大鼠基底前脑的抗氧化能力,降低基底前脑的氧化损伤,可用于女性更年期后老年性痴呆的防治。     

小儿支气管肺炎患者中性粒细胞吞噬及细胞内杀菌功能与脂质过氧化关系的探讨

目的：探讨了小儿支气管肺炎患者血液中性粒细胞吞噬及细胞内杀菌功能与脂质过氧化的关系。方法：采用普通酵母菌对62例患者及35例正常人进行中性粒细胞吞噬和细胞内杀菌功能试验和化学比色法测定血浆丙二醛（MDA）、谷胱甘肽过氧化物酶（GSH—PX）含量，放免法测超氧化物歧化酶（SOD），并与35名正常健康人作比较。结果：小儿支气管肺炎患儿在治疗前中性粒细胞吞噬及细胞内杀菌功能均明显低于正常人（P〈0．01），S01）、GSH-PX低于正常人组（P〈0．01），而MDA显著地高于正常人组（P〈0．01），相关分析显示，中性粒细胞吞噬及细胞内杀菌功能与MDA呈显著负相关（r=-0．3118，-0．3024，P〈0．05），经10d治疗后则与正常人比较无显著性差异（P〉0．05）。结论：检测小儿支气管肺炎患儿血液中性粒细胞吞噬及细胞内杀菌功能与脂质过氧化的关系对临床诊断、治疗和预后观察有重要的临床价值。     

赛庚啶对内毒素血症小鼠氧化损伤的对抗作用

目的:研究赛庚啶对内毒素(LPS)血症小鼠氧化损伤的对抗作用。方法:小鼠尾静脉注射LPS,造成内毒素血症模型,观察赛庚啶能否提高小鼠24h存活率,并测定血浆NO的水平,心、肝、肾和脑组织中SOD和GSH-Px活力以及脂质过氧化产物MDA含量。结果:赛庚啶预防给药能够显著提高致死量LPS攻击后小鼠24h的存活率,使血浆NO2-/NO3-的水平显著降低,其中高剂量组SOD和GSH-Px活力增高,MDA含量降低。低剂量组SOD活力增高,但肝和脑组织中MDA含量下降不明显,肝和肾组织GSH-Px活力无明显增高。结论:赛庚啶预防给药能够防治LPS血症,改善小鼠LPS血症时重要脏器氧化性损伤状态,抑制血浆NO水平过度升高。