Oxidative stress in elite athletes training at moderate altitude and at sea level

Using a controlled parallel group longitudinal trial design, we investigated the effects of different training interventions on the prooxidant/antioxidant status of elite athletes: living and training at moderate altitude for 3 (Hi-Hi3) and 4 weeks (Hi-Hi), and for 4 weeks too, living high and training high and low (Hi-HiLo) and living and training at sea level (Lo-Lo). From 61 swimmers, 54 completed the study. Nitrites, carbonyls, and lipid peroxidation (LPO) levels were assessed in plasma. Enzymatic antioxidants glutathione peroxidase (GPx) and glutathione reductase (GRd), and non-enzymatic antioxidants total glutathione (GST), reduced glutathione (GSH) and oxidized glutathione (GSSG) were analysed in the erythrocyte fraction. At the end of the intervention, nitrites levels were similar in all altitude groups but higher than in the Lo-Lo controls (P?=?.02). Hi-HiLo had greater GPx activity than Hi-Hi and Hi-Hi3 during most of the intervention (P?≤?.001). GRd activity was higher in Lo-Lo than in Hi-Hi at the end of the training camp (P?≤?.001). All groups showed increased levels of LPO, except Lo-Lo, and carbonyls at the end of the study (P?≤?.001). Training at altitude for 3 or 4 weeks drives oxidative stress leading to cellular damage mainly by worsening the antioxidant capacities. The GSSG/GSH ratio appears to be related to perceived exertion and fatigue. The stronger antioxidant defence showed by the Hi-HiLo group suggests an inverse relationship between redox alterations and performance. Further studies are required to investigate the role of oxidative stress in acclimatization, performance, and health.     

An Integrated Approach of the Potential Underlying Molecular Mechanistic Paradigms of SARS-CoV-2-Mediated Coagulopathy

Coronavirus disease 2019 (Covid-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a pandemic disease which has affected more than 6.2 million people globally, with numbers mounting considerably daily. However, till date, no specific treatment modalities are available for Covid-19 and also not much information is known about this disease. Recent studies have revealed that SARS-CoV-2 infection is associated with the generation of thrombosis and coagulopathy. Fundamentally, it has been believed that a diverse array of signalling pathways might be responsible for the activation of coagulation cascade during SARS-CoV-2 infection. Henceforth, a detailed understanding of these probable underlying molecular mechanistic pathways causing thrombosis in Covid-19 disease deserves an urgent exploration. Therefore, in this review, the hypothetical crosstalk between distinct signalling pathways including apoptosis, inflammation, hypoxia and angiogenesis attributable for the commencement of thrombotic events during SARS-CoV-2 infection has been addressed which might further unravel promising therapeutic targets in Covid-19 disease.     

低氧训练对肥胖机体体重和血脂的影响

肥胖现已成为世界范围内的一大困扰,是一种被视为威胁健康的重要疾病。近年来,研究表明从高原训练迁移而来的模拟低氧训练的模式,对减轻体重和血脂代谢有很好的改善效果,并且受到了很多关注。本研究主要通过搜集相关文献,对其进行分析和总结,探究低氧训练对机体减重的效果和可能的机制,以及对血脂等指标的影响,从而促进低氧运动的应用。     

低氧训练与低氧诱导因子-1的研究进展

在许多类型的细胞中均发现低氧可诱导低氧诱导因子-1(HIF-1)水平的增高,说明存在1个普遍的氧感受和低氧信号转导机制。其中HIF-l起着重要的作用。本文综述了HIF-1的结构、功能和活性调节、与低氧信号转导的关系及低氧训练对低氧诱导因子-l的影响等方面的研究进展,为运动与低氧适应提供理论依据。     

缺氧及不同负荷运动对大鼠肺动脉平滑肌细胞HO-CO系统的影响

血红素加氧酶(heme oxygenase HE)是血红素降解过程中的限速酶,可催化血红素分解产生一氧化碳(CO),运动和缺氧会引起HO-CO系统的变化。本文就缺氧及不同负荷运动对大鼠肺动脉平滑肌细胞HO-CO系统的影响作以综述,为科学的运动训练及防止缺氧性肺动脉高压的发生提供一定的理论依据。     

Do Over 200 Million Healthy Altitude Residents Really Suffer from Chronic Acid–Base Disorders?

As the oxygen tension of inspired air falls with increasing altitude in normal subjects, hyperventilation ensues. This acute respiratory alkalosis, induces increased renal excretion of bicarbonate, returning the pH back to normal, giving rise to compensated respiratory alkalosis or chronic hypocapnia. It seems a contradiction that so many normal people at high altitude should permanently live as chronic acid–base patients. Blood gas analyses of 1,865 subjects at 3,510 m, reported a P _aCO₂ (arterial carbon dioxide tension ± SEM) = 29.4 ± 0.16 mmHg and pH = 7.40 ± 0.005. Base excess, calculated with the Van Slyke sea level equation, is −5 mM (milliMolar or mmol/l) as an average, suggesting chronic hypocapnia. THID, a new term replacing “Base Excess” is determined by titration to a pH of 7.40 at a P _aCO₂ of 5.33 kPa (40 mmHg) at sea level, oxygen saturated and at 37°C blood temperature. Since our new modified Van Slyke equations operate with normal values for P _aCO₂ at the actual altitude, a calculation of THID will always result in normal values—that is, zero.     

慢性重复性低氧小鼠的红细胞增多效应

小鼠暴露于低压舱(0.42atm,22h/day)连续9天。结果表明,慢性重复低氧后,小鼠的血清促红细胞生成素(EPO)浓度迅速增高,第3天达峰值,其后迅速递减,但直至低氧后第9天,EPO仍高于低氧前水平(P<0.01)。低氧期间,小鼠的红细胞比容持续递增(P<0.01),而血浆容量无明显改变。伴随红细胞生成的增加,EPO生成存在反馈性抑制现象。     

高住低训对大鼠体重和骨骼肌形态学影响

以SD大鼠为研究对象,分为常氧安静组、常氧运动组、低氧暴露组、高住低训组4大组.分别检测各组各时期大鼠体重和腓肠肌质量及肌纤维面积的变化.结果:(1)28天高住低训后大鼠体重显著下降(p<0.05);(2)28天常氧运动组、低氧暴露组、高住低训组肌肉重量显著低于对照,其中高住低训组最低,低氧暴露组其次,常氧运动组差异最小(P<0.05);(3)28天低氧暴露导致大鼠肌肉萎缩,肌纤维横截面积明显减小(p<0.05).结论:高住低训抑制大鼠肌肉的生长,可能对骨骼肌的运动机能有不利的影响.     

高原训练的研究进展

高原训练随着竞技体育的日趋激烈的发展,已成为国内外体育界研究的热点。本文就高原训练的发展、模拟高原训练的方法(间歇性低氧训练、高住低训)以及高原训练对运动能力、各系统(如呼吸系统、心血管系统等)和几项指标的影响等进行了综述。     

低氧对体成分及骨骼肌蛋白质分解代谢的影响

了解低氧和运动对体成分及骨骼肌蛋白质分解代谢的影响，对了解肌肉收缩性能的变化有着重要的意义。为此，本文综合阐述了反映蛋白分解代：谢的一些指标及变化规律和意义，并重点介绍了低氧对体重、体成分、骨骼肌质量的影响，以及它们与蛋白分解代谢的关系，对高原训练有相当的参考价值。