Progress in Researches on the Effect of Acupuncture in Antagonizing Oxygen Stress

Oxidation and free radicals participate in the pathological process of multiple diseases in organisms, and acupuncture shows good effect in antagonizing oxygen stress (OS). This article reviews the effect of acupuncture in antagonizing oxygen stress and the mechanism of its anti-free radical effect in various diseases. The authors hold that acupuncture not only has a chain-blocking effect, but also has preventive and repairing effects of anti-oxidation. And anti-OS action is one of the important mechanisms of acupuncture.

Response of Nitrate Metabolism in Seedlings of Oilseed Rape(Brassica napus L.) to Low Oxygen Stress

In order to understand the response of nitrate metabolism in seedlings of oilseed rape （Brassica napus L.） to low oxygen stress （LOS）, two cultivars were studied at different light, LOS time and exogenous nitrate concentrations under hydroponic stress. Results show that N-uptake and dry matter of rape seedlings were decreased after LOS stress while nitrate accumulation （NA） under LOS was induced by darkness. Nitrate accumulation peaked at 3 d while root activity （RA, deifned as dehydrogenase activity） decreased with prolonged waterlogging exposure. Exogenous nitrate signiifcantly elevated NA and RA. Tungstate （TS） and LOS inhibited nitrate reductase （NR） activity while NR transcription and activity were enhanced by exogenous nitrate. Low oxygen stress stimulated the activity of superoxide dismutase （SOD） and peroxidase （POD） slightly, but inhibited that of catalase （CAT）. B. napus L. Zhongshuang 10 （ZS10）, a LOS tolerant cultivar, displayed smaller decrease upon dry matter under LOS, higher NA in darkness and lower NA in light than B. napus L. Ganlan CC （GAC）, a LOS sensitive variety. ZS10 had lower NA and higher RA after waterlogging and exogenous nitrate treatment, and higher NR activity under TS inhibition than GAC, but the activity of antioxidant enzymes did not change under LOS. The results indicate that nitrate metabolism involved tolerance of rape seedlings to LOS, with lower accumulation and higher reduction of nitrate being related to higher LOS tolerance of rape seedlings exposed to waterlogging.

Hyperbaric oxygen preconditioning improves postoperative cognitive dysfunction by reducing oxidant stress and inflammation

Postoperative cognitive dysfunction is a crucial public health issue that has been increasingly studied in efforts to reduce symptoms or prevent its occurrence. However, effective advances remain lacking. Hyperbaric oxygen preconditioning has proved to protect vital organs, such as the heart, liver, and brain. Recently, it has been introduced and widely studied in the prevention of postoperative cognitive dysfunction, with promising results. However, the neuroprotective mechanisms underlying this phenomenon remain controversial. This review summarizes and highlights the definition and application of hyperbaric oxygen preconditioning, the perniciousness and pathogenetic mechanism underlying postoperative cognitive dysfunction, and the effects that hyperbaric oxygen preconditioning has on postoperative cognitive dysfunction. Finally, we conclude that hyperbaric oxygen preconditioning is an effective and feasible method to prevent, alleviate, and improve postoperative cognitive dysfunction, and that its mechanism of action is very complex, involving the stimulation of endogenous antioxidant and anti-inflammation defense systems.

Stress corrosion cracking behavior of 310S in supercritical water with different oxygen concentrations

The effect of dissolved oxygen(DO) on the stress corrosion cracking(SCC) of 310 S in supercritical water was investigated using slow-strain-rate tensile tests.The tensile properties, fracture morphology, and distribution of the chemical composition of the oxide were analyzed to evaluate the SCC susceptibility of 310 S. The results showed that the rupture elongation decreased significantly as the degree of DO increased. A brittle fracture mode was observed on the fracture surface, and only intergranular cracking was observed on the surface of the gauge section, regardless of the DO. Cracks were widely distributed on the gauge surface near the fracture surface.Oxides were observed in the cracks with two-layered structures, i.e., a Cr-rich inner oxide layer and an Fe-rich outer oxide layer.

Effects of Water Stress on Reactive Oxygen Species Generation and Protection System in Rice During Grain-Filling Stage

Rice is one of the main staple food crops in the world, but it may suffer serious water stress during growth period. Water stress during grain filling results in decreased grain yeild, but its mechanism generating and scavenging the active oxygen is unclear under continuance of the water stress. The experiment was carried out in growth chamber to investigate the effects of water stress on the production of superoxide free radical （O2）, hydrogen peroxide （H202）, malondialdehyde （MDA）, reduced glutathione （GSH）, ascorbic acid （AsA）, and antioxidative enzyme activities in three rice hybrids with differing drought resistant under both normal and drought conditions during grain-filling stage. The results showed that water stress aggravated the membrane lipid peroxidation in rice leaves, which was more severe in less drought resistant hybrids than that in more tolerant ones. Also O2＇ and H2O2 accumulated more rapidly in less drought resistant hybrids than that in more tolerant ones. During water stress, decreases of GSH, AsA, chlorophyll, and relative water contents in more drought resistant hybrids were obvious less than those in less tolerant ones. Activities of superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD） in/eaves increased obviously in 0-14 d after heading and subsequently decreased rapidly, and those in more drought resistant hybrids were more than those in less tolerant ones. The results showed that changes of O2, H2O2, MDA, GSH, and AsA contents and antioxidative enzyme activities correlated significantly to drought resistance of rice hybrids, and more drought resistant hybrids possessed high ant oxidation capacity.

N-acetylcysteine attenuates reactive-oxygen-speciesmediated endoplasmic reticulum stress during liver ischemia-reperfusion injury

AIM:To investigate the effects of N-acetylcysteine(NAC) on endoplasmic reticulum(ER) stress and tissue injury during liver ischemia reperfusion injury(IRI).METHODS:Mice were injected with NAC(300 mg/kg) intraperitoneally 2 h before ischemia.Real-time polymerase chain reaction and western blotting determined ER stress molecules(GRP78,ATF4 and CHOP).To analyze the role of NAC in reactive oxygen species(ROS)-mediated ER stress and apoptosis,lactate dehydrogenase(LDH) was examined in cultured hepatocytes treated by H2O2 or thapsigargin(TG).RESULTS:NAC treatment significantly reduced the level of ROS and attenuated ROS-induced liver injury after IRI,based on glutathione,malondialdehyde,serum alanine aminotransferase levels,and histopathology.ROS-mediated ER stress was significantly inhibited in NAC-treated mice.In addition,NAC treatment significantly reduced caspase-3 activity and apoptosis after reperfusion,which correlated with the protein expression of Bcl-2 and Bcl-xl.Similarly,NAC treatment significantly inhibited LDH release from hepatocytes treated by H2O2 or TG.CONCLUSION:This study provides new evidence for the protective effects of NAC treatment on hepatocytes during IRI.Through inhibition of ROS-mediated ER stress,NAC may be critical to inhibit the ER-stressrelated apoptosis pathway.

Organogermanium (Ge-132) Suppresses Activities of Stress Enzymes Responsible for Active Oxygen Species in Monkey Liver Preparation

Assays of stress enzymes related to active oxygen species were performed by using an in vitro preparation from the liver of a monkey (Japanese Macaque). Ge-132, an organic germanium compound, viz. poly-trans-[(2-carboxyethyl) germasesquioxane] [(GeCH2CH2COOH)2O3]n, suppressed the activities of NADH-dependent oxidase and NADPH-dependent oxidase [NAD(P)H-OD] and xanthine oxidase (XOD) as superoxide-forming enzymes, while promoting the activities of superoxide dismutase (SOD) as a superoxide-scavenging enzyme and catalase (CAT) as an enzyme responsible for degradation of hydrogen peroxide (H2O2). The evidence suggests that the levels of active oxygen species such as and H2O2 would be reduced by Ge-132. The possible connection between Ge-132 and activities of stress enzymes is discussed on the basis of these results.

Edaravone protects against oxygen-glucose-serum deprivation/restoration-induced apoptosis in spinal cord astrocytes by inhibiting integrated stress response

We previously found that oxygen-glucose-serum deprivation/restoration（OGSD/R） induces apoptosis of spinal cord astrocytes, possibly via caspase-12 and the integrated stress response, which involves protein kinase R-like endoplasmic reticulum kinase（PERK）, eukaryotic initiation factor 2-alpha（eIF2α） and activating transcription factor 4（ATF4）. We hypothesized that edaravone, a low molecular weight, lipophilic free radical scavenger, would reduce OGSD/R-induced apoptosis of spinal cord astrocytes. To test this, we established primary cultures of rat astrocytes, and exposed them to 8 hours/6 hours of OGSD/R with or without edaravone（0.1, 1, 10, 100 μM） treatment. We found that 100 μM of edaravone significantly suppressed astrocyte apoptosis and inhibited the release of reactive oxygen species. It also inhibited the activation of caspase-12 and caspase-3, and reduced the expression of homologous CCAAT/enhancer binding protein, phosphorylated（p）-PERK, p-eIF2α, and ATF4. These results point to a new use of an established drug in the prevention of OGSD/R-mediated spinal cord astrocyte apoptosis via the integrated stress response.

Effect of Cd, Pb Stress on the Activated Oxygen Scavenging System in Tobacco Leaves

The effect of Cd, Pb stress on the activated oxygen scavenging system indicates thatthe content of chlorophyll, chlorophyll a/b ratio and the activity of CAT gradually decrease,the activity of SOD increases first and then decreases, and the activity of POD gradually increases with increasing concentrations of Cd and Ph. Between Cd and Ph there is synergism inthe activated oxygen scavenging system. The results show that the stress of Cd and Pb can affect the scavenging system of activated oxygen and result in imbalance of activated oxygenmetabolism.

Regulation of heme oxygenase expression by alcohol,hypoxia and oxidative stress

AIM:To study the effect of both acute and chronic alcohol exposure on heme oxygenases(HOs) in the brain,liver and duodenum.METHODS:Wild-type C57BL/6 mice,heterozygous Sod2 knockout mice,which exhibit attenuated manganese superoxide dismutase activity,and liver-specific ARNT knockout mice were used to investigate the role of alcohol-induced oxidative stress and hypoxia.For acute alcohol exposure,ethanol was administered in the drinking water for 1 wk.Mice were pair-fed with regular or ethanol-containing Lieber De Carli liquid diets for 4 wk for chronic alcohol studies.HO expression was analyzed by real-time quantitative polymerase chain reaction and Western blotting.RESULTS:Chronic alcohol exposure downregulated HO-1 expression in the brain but upregulated it in the duodenum of wild-type mice.It did not alter liver HO-1 expression,nor HO-2 expression in the brain,liver or duodenum.In contrast,acute alcohol exposure decreased both liver HO-1 and HO-2 expression,and HO-2 expression in the duodenum of wild-type mice.The decrease in liver HO-1 expression was abolished in ARNT+/-mice.Sod2+/-mice with acute alcohol exposure did not exhibit any changes in liver HO-1 and HO-2 expression or in brain HO-2 expression.However,alcohol inhibited brain HO-1 and duodenal HO-2 but increased duodenal HO-1 expression in Sod2+/-mice.Collectively,these findings indicate that acute and chronic alcohol exposure regulates HO expression in a tissue-specific manner.Chronic alcohol exposure alters brain and duodenal,but not liver HO expression.However,acute alcohol exposure inhibits liver HO-1 and HO-2,and also duodenal HO-2 expression.CONCLUSION:The inhibition of liver HO expression by acute alcohol-induced hypoxia may play a role in the early phases of alcoholic liver disease progression.

Effects of Exogenous NO on Active Oxygen Metabolism in Cucumber Seedlings under NaCl Stress

Employing nutrient solution hydroponic method,the effects of exogenous nitric oxide（NO）on the growth and active oxygen metabolism in cucumber（Cucumis sativus L.）seedlings under NaCl stress were investigated.The results indicated that NaCl treatment significantly inhibited the growth of cucumber seedlings,while exogenous NO could significantly alleviate the inhibitory effects of NaCl stress on seedling growth.Especially,0.1 mmol/L SNP treatment exhibited better effects than 0.5 mmol/L SNP treatment on alleviating NaCl stress.Under 0.1 mmol/L NaCl stress,adding 0.1 mmol/L exogenous NO could significantly decrease the generation rate of O·-2and MDA content,significantly improve soluble protein content and enhance the activities of SOD,POD and CAT,thus reducing the damage of salt stress to cucumber seedlings.

Effects of salt-alkali stress on active oxygen metabolism in roots of Spiraea × bumalda 'Gold Mound' and Spiraea × bumalda 'Gold Flame'

Under artificially-simulated complex salt-alkali stress, the levels of active oxygen metabolism in roots were studied using three-year-old cutting seedlings of Spiraea × bumalda ‘Gold Mound＇ and Spiraea × bumalda ‘Gold Flame＇. The present study aimed at exploring the antioxidant capacity in roots of spiraeas and revealing their adaptability to salt-alkali stress. Results indicate that the oxygen free radicals contents, electrolyte leakage rates and MDA contents in roots of Spiraea × bumalda ＇Gold Mound＇ and Spiraea × bumalda ＇Gold Flame＇ show an increasing tendency with the increases of the salinity and pH value, whereas the activities of superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） all increased firstly and then decreased. With the increase in intensity of salt-alkali stress, the CAT activity in roots of Spiraea × bumalda ‘Gold Flame＇ is higher and the increasing extents in the oxygen free radicals contents, electrolyte leakage rates as well as MDA contents are lower compared with Spiraea × bumalda ‘Gold Mound＇, indicating that Spiraea × bumalda ‘Gold Flame＇ has a stronger antioxidant capacity.

Production of reactive oxygen species by freezing stress and the protective roles of antioxidant enzymes in plants

As one of the most severe environmental stresses, freezing stress can determine native flora in nature and severely reduce crop production. Many mechanisms have been proposed to explain the damage induced by freezing-thawing cycle, and oxidative stress caused by uncontrollable production of harmful reactive oxygen species (ROS) are partially contributed to causing the injury. Plants in temperate regions have evolved a unique but effective metabolism of protecting themselves called cold acclimation. Cold-acclimating plants undergo a complex but orchestrated metabolic process to increase cold hardness triggered by exposure to low temperature and shortened photoperiod and achieve the maximum freezing tolerance by a concerted regulation and expression of a number of cold responsive genes. A complicated enzymatic system have been evolved in plants to scavenge the ROS to protect themselves from oxidative stress, therefore, cold-acclimating plants are expected to increase the de novo synthesis of the genes of antioxidant genes. Indeed, many antioxidant genes increase the expression levels in response to low temperature. Furthermore, the higher expression of many antioxidant enzymes are positively correlated to inducing higher tolerance levels against freezing. All the information summarized here can be applied for developing crop and horticultural plants to have more freezing tolerance for higher production with better quality. There have been extensive studies on the activities of antioxidant enzymes and the gene regulation, however, more researches will be required in near future to elucidate the most effective antioxidant enzymes to induce highest freezing tolerance in a crop plant in a transformation process or a breeding program.

Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming

The world is projected to experience an approximate doubling of atmospheric CO_2 concentration in the next decades. Rise in atmospheric CO_2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 ℃-5.8 ℃ by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO_2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species(ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress(OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O_2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to longevity of animals will become very crucial challenge to biologists of the present millennium.

Determination of Heat Stress and Ultra Low Oxygen in Chestnut Storage under Control and Modified Atmospheres

The effects of heat stress (HS) and ultra low oxygen (ULO) in controlled (CA) or modified (MA) atmosphere on chestnut (Castanea sativa L. cv. Rodiana) fruit quality and storability were investigated. Chestnuts exposed to ULO (1% O2 for 1 h) or dipped in water bath (at 55?C for 15 min) and then stored to CA or MA conditions at 6?C for up to 90 days. The HS dipping and storage in CA or MA increased sprouting (up to 60%) as well as mould severe on chestnuts com-paring with the control. In MA conditions, HS and ULO increased respiration rate. Total starch content increased (up to 30%) in MA-HS and MA-ULO treatments comparing with the control the first 60 days of storage. The first 30 days of CA and MA storage, chestnut moisture content decreased. No major differences observed in total sugar, total fat and total phenolic content as well as in the incidence of hole with or without worm in chestnut fruit. Following sensory evaluation, 57% of panelist marked differences among treatments, while the greater preference (67%) observed in chestnut treated with HS and stored in MA. Additionally, MA-HS enhanced (up to 30%) the chestnut appearance while no difference observed in aroma, sweetness and texture among treatments and storage conditions. Thus, the impacts of HS on chestnuts maintain fruit quality, with benefits in CA storage, as increased panelists’ preference.

不同麻醉深度指数下拔管在扁桃体低温等离子射频消融术患儿中的应用效果比较

目的:比较不同麻醉深度指数(NT值)下拔管在扁桃体低温等离子射频消融术患儿中的应用效果。方法:选取2021年7月至2022年4月于该院行扁桃体低温等离子射频消融术的76例患儿进行前瞻性研究,按照随机数字表法将其分为对照组和观察组各38例。两组均行气管插管全身麻醉,对照组于NT值为95~100时拔管,观察组于NT值为80~94时拔管。比较两组不同时间[停止麻醉维持即刻(T_(0))、拔管后即刻(T_(1))、拔管后10 min(T_(2))]血流动力学指标(心率、平均动脉压、呼吸频率)水平、不同时间(拔管前、拔管后30 min)应激指标[皮质醇(Cor)、肾上腺素(E)]水平、不同时间(T_(0)、T_(1)、T_(2))局部脑氧饱和度(rSO_(2))水平和不良反应发生率。结果:T_(1)、T_(2)时,两组平均动脉压、心率、呼吸频率均高于T_(0)时,但观察组低于对照组,差异有统计学意义(P<0.05);拔管后30 min,两组Cor、E水平均高于拔管前,但观察组低于对照组,差异有统计学意义(P<0.05);T_(0)、T_(1)、T_(2)时,两组rSO_(2)水平比较,差异均无统计学意义(P>0.05);观察组不良反应发生率为5.26%(2/38),低于对照组的21.05%(8/38),差异有统计学意义(P<0.05)。结论:NT值为80~94时拔管应用于扁桃体低温等离子射频消融术患儿可改善血流动力学指标和应激指标水平,降低不良反应发生率,效果优于NT值为80~94时拔管。

橙皮素抑制氧化应激影响软骨细胞的炎性退变

背景:研究表明,橙皮素可以通过多种机制或者信号通路对软骨细胞产生保护作用,但其保护机制尚未完全阐明。目的:探讨橙皮素对脂多糖诱导的软骨细胞炎性退变的影响。方法:体外提取、培养SD乳鼠关节软骨细胞,采用番红O染色鉴定。通过MTT法检测细胞毒性确定最佳橙皮素干预浓度。将软骨细胞随机分为3组:对照组、模型组和实验组,后2组采用脂多糖诱导软骨细胞建立骨关节炎细胞模型,实验组造模后给予橙皮素干预24 h。采用Calcein-AM/EthD-Ⅰ染色检测细胞活性,免疫组化染色检测软骨特异性Ⅱ型胶原的表达,活性氧检测试剂盒检测软骨细胞内活性氧水平,ELISA检测软骨细胞内抗氧化剂总谷胱甘肽水平,qRT-PCR检测炎症基因白细胞介素1β、白细胞介素6、肿瘤坏死因子α和软骨特异性基因Ⅱ型胶原基因的表达。结果与结论:①番红O染色结果表明,提取的细胞为软骨细胞;②细胞毒性实验表明0.5μmol/L橙皮素干预软骨细胞活力最明显;③与对照组比较,模型组软骨细胞增殖能力降低,活性氧水平升高,总谷胱甘肽水平下降,Ⅱ型胶原降解增加,白细胞介素1β、白细胞介素6和肿瘤坏死因子α基因表达水平升高,软骨特异性Ⅱ型胶原基因表达水平下降,差异均有显著性意义(P<0.05);④与模型组比较,实验组软骨细胞增殖能力上升,活性氧水平下降,总谷胱甘肽水平上升,Ⅱ型胶原降解减少,白细胞介素1β、白细胞介素6和肿瘤坏死因子α基因表达水平下降,软骨特异性Ⅱ型胶原基因表达水平升高(P<0.05)。结果表明:橙皮素对脂多糖诱导的骨关节炎软骨细胞炎性退变具有保护作用,其机制可能与橙皮素抑制活性氧介导的氧化应激有关。

不同氧浓度下髓核细胞中PI3K/Akt/HIF-1α信号通路表达对延缓椎间盘退变的意义

背景:椎间盘退变是一种由于细胞凋亡、氧化应激、炎症反应等多种因素共同作用导致的疾病,目前认为其核心在于髓核细胞退变与凋亡,然而具体病理机制尚不明确。目的:通过探究不同氧浓度下髓核细胞中磷脂酰激醇-3-激酶(phosphatidylinositol-3kinase,PI3K)/蛋白激酶B(protein kinase B,Akt)/缺氧诱导因子1α(hypoxia-inducible factor 1-alpha,HIF-1α)信号通路的表达及髓核细胞凋亡情况,明确不同氧浓度下髓核细胞的生物学特性,探讨椎间盘退变的机制。方法:取人正常及退变髓核细胞,取第2代细胞用于影像学鉴定,取第3代细胞分别采用37℃、空气、100%湿度环境,100μmol/L CoCl_(2)浓度的Leibovitz’s培养基、100μmol/L H_(2)O_(2)浓度的10%胎牛血清培养基构建常氧、低氧及氧化应激环境,将细胞分为正常髓核细胞+低氧环境、正常髓核细胞+常氧环境、正常髓核细胞+氧化应激环境、退变髓核细胞+低氧环境、退变髓核细胞+常氧环境、退变髓核细胞+氧化应激环境6组;采用CCK-8法检测细胞活力及增殖情况,流式细胞术检测细胞凋亡率,RT-PCR、Western-blot检测PI3K、AKT、HIF-1α的蛋白及mRNA表达情况。结果与结论:①在不同的氧浓度下,正常及退变髓核细胞的增殖率随氧浓度升高而下降,凋亡率随氧浓度升高而上升(P<0.05),以正常髓核细胞+低氧环境为对照组,细胞正常与否对凋亡率影响极为显著(P<0.001),氧浓度对髓核细胞增殖率与凋亡率影响极为显著(P<0.001),细胞是否退变与氧浓度二者交互作用对髓核细胞增殖率与凋亡率影响显著(P<0.05)。②在不同的氧浓度下,正常髓核细胞中低氧环境下PI3K、AKT、HIF-1α的蛋白及mRNA表达最高,氧化应激环境下其次,常氧环境下最低;退变髓核细胞中3项指标的蛋白和mRNA表达随氧浓度升高而下降;正常髓核细胞中PI3K、Akt的蛋白、mRNA表达均显著高于退变髓核细胞(P<0.05)。以正常髓核细胞+低氧环境为对照组,髓核细胞正常或退变及氧浓度对上述3项指标的蛋白和mRNA表达影响均极为显著,二者交互作用对3项指标的蛋白和mRNA表达影响极为显著(P<0.001)。③结果表明,髓核细胞的增殖、凋亡与氧浓度和细胞自身功能状态密切相关,PI3K/Akt/HIF-1α信号通路在不同细胞功能状态及不同氧浓度环境下具有拮抗调节作用,其机制可能与PI3K/Akt信号通路被激活,并翻译转录HIF-1α,从而维持活性氧自由基代谢平衡有关。该通路对于抑制氧化应激,拮抗髓核细胞凋亡,进而延缓椎间盘退变具有重要意义。

氧化应激在年龄相关性眼病中的作用机制研究进展

氧化应激(OS)是指人体在内外环境的有害刺激下,氧化与抗氧化作用失衡,导致活性氧自由基和活性氮自由基堆积所产生的生理和病理反应。它是导致许多急慢性疾病和衰老的重要机制。眼球作为人体的视觉器官,长时间与外界环境接触,加上其代谢旺盛,其结构更易受到OS的损伤,引起眼部疾病的发生。因此,文章就氧化应激因素及其在年龄相关性眼病中的作用机制进行综述,并对目前主要的老年性眼病的OS机制分别进行阐述。

水稻热激转录因子HsfA2b调控非生物胁迫抗性的功能分析

【目的】水稻在生长发育过程中,常会受到各种非生物胁迫而严重影响产量。热激转录因子作为植物抗逆过程中的一个重要元件,通过调控一系列胁迫响应基因的表达以提高植物抗逆性。探究水稻热激转录因子OsHsfA2b调控非生物胁迫的功能与初步机理,为培育水稻抗逆新品种提供了优异基因资源和理论支撑。【方法】通过构建OsHsfA2b过量表达和RNAi的转基因水稻,分别观察水稻幼苗在高温、低温、干旱和高盐处理后的抗逆表型,统计存活率。同时,在逆境胁迫处理后,通过DAB染色检测水稻叶片活性氧(ROS)含量及RT-qPCR检测抗氧化途径相关基因OsSOD和OsCAT的表达量,分析OsHsfA2b对抗氧化途径的调控作用。【结果】在高温、低温、干旱和高盐等非生物胁迫条件下,水稻热激转录因子OsHsfA2b被显著诱导表达。与野生型NPB相比,OsHsfA2b过量表达转基因水稻对非生物胁迫的抗性明显增强,植株损伤程度较轻,存活率提高。相反,OsHsfA2b-RNAi水稻对非生物胁迫更加敏感,植株损伤严重,存活率降低。此外,在非生物胁迫条件下,OsHsfA2b过量表达转基因水稻比NPB和OsHsfA2bRNAi水稻体内活性氧的含量减少,并且OsHsfA2b显著诱导了抗氧化途径相关基因OsSOD和OsCAT的表达,OsHsfA2b参与抑制水稻体内活性氧的积累以降低逆境胁迫诱导的活性氧大量积累对植株的伤害。【结论】非生物胁迫下,水稻热激转录因子OsHsfA2b被显著诱导表达,可通过抗氧化途径正调控水稻对逆境胁迫的抗性。