白藜芦醇对氧化应激环境中HUVECs细胞衰老、增殖、凋亡的影响及机制

目的探讨白藜芦醇(RSV)在氧化应激环境中对人脐静脉内皮细胞(HUVECs)衰老、增殖及凋亡的影响,并对相关机制进行探索。方法利用β-半乳糖苷酶染色HUVECs衰老的细胞并记录阳性细胞数,观察过氧化氢(H_2O_2)单独处理以及联合RSV后,细胞衰老情况的变化;采用长时程动态活细胞成像及分析系统检测H_2O_2单独处理以及联合RSV后细胞增殖能力的变化并绘制生长曲线;利用流式细胞技术检测H_2O_2单独及联合RSV对HUVECs细胞周期及细胞凋亡情况的影响;采用Western印迹检测相关蛋白表达情况。结果 HUVECs经H_2O_2处理后,相比于H_2O_2组,RSV组β-半乳糖苷酶染色阳性细胞比例明显减低,细胞增殖能力增强,二者差异显著(P0.05);相比于RSV组,H_2O_2组细胞周期多被阻滞在G1期,且细胞增殖相关蛋白(p-AKT和pERK)表达减少,而衰老相关蛋白p53、 p21、 p16、 p-Rb表达明显增多;而RSV可拮抗H_2O_2对HUVECs的作用,使HUVECs凋亡细胞数显著减少,Survivin蛋白表达明显增多(P0.05)。结论 RSV可抑制氧化应激环境中HUVECs细胞的衰老及凋亡、促进细胞增殖,对HUVECs细胞具有保护作用,其机制与RSV改变相关蛋白表达有关。     

硫化氢通过SIRT1抗内皮细胞衰老

目的探讨外源性硫化氢在人脐静脉内皮细胞(HUVEC)衰老中的作用及分子机制。方法用25μmol/L H2O2诱导HUVEC衰老,通过检测β-半乳糖苷酶计算细胞衰老率。检测不同浓度(15、30、60及120μmol/L)的硫氢化钠作用下内皮细胞衰老标志物β-半乳糖苷酶的表达,Western blot分析沉默信息调节因子1(SIRT1)蛋白的表达。结果 HUVEC经25μmol/L H2O2处理1 h后,β-半乳糖苷酶阳性细胞率为12.2%±1.30%;经60μmol/L硫氢化钠干预48 h后,β-半乳糖苷酶阳性细胞率显著降低,为4.6%±1.14%,两组相比差异显著(P<0.05);与对照组比较,60μmol/L硫氢化钠干预48 h后SIRT1蛋白表达显著上调(P<0.05),而用SIRT1抑制剂(NAM)可减弱硫氢化钠此作用(β-半乳糖苷酶阳性细胞率为12.0%±1.58%)。结论硫化氢能通过上调SIRT1表达抵抗H2O2诱导HUVEC衰老。     

外源性Rb基因对神经细胞衰老的影响

目的　观察外源性 Rb基因对神经细胞衰老的影响 ,并探讨 Rb基因对神经细胞 P2 1基因表达的调控。方法　用外源性 Rb基因重组腺病毒载体感染体外培养的胚胎大鼠神经细胞 ,以β-半乳糖苷酶染色观察神经细胞的衰老变化 ,用免疫组化法测定 P2 1蛋白表达水平。结果　外源性Rb基因导入神经细胞后 ,P2 1蛋白水平显著增高 ,与衰老相关的 β-半乳糖苷酶表达也增加。结论　 Rb基因可能通过上调 P2 1基因表达促进神经细胞衰老。     

大鼠胰岛B细胞长寿基因SIRT1与转录调节因子FOXO1表达及其相关性研究

目的探讨大鼠胰岛B细胞在衰老进程中长寿基因SIRT1与转录调节因子FOXO1表达的相关性。方法2005年10月至2006年10月,在汕头大学医学院第二附属医院将11只18月龄健康雄性SD大鼠随机分为热量限制(CR)组6只和正常喂养对照组5只,饲养6个月后取胰尾组织,应用免疫组化染色分别检测胰岛中SIRT1、FOXO1和胰岛素表达及分布,衰老相关β-半乳糖苷酶(β-Gal)染色以反映胰岛B细胞衰老情况。结果SIRT1与FOXO1均可表达于胰岛细胞胞浆、胞核中;β-Gal和胰岛素表达于细胞浆中;与对照组大鼠相比,CR组大鼠胰岛SIRT1表达量较多(P<0.05),衰老相关β-Gal染色强度较弱(P<0.01),胰岛素表达量较低(P<0.05),但FOXO1表达量差异无显著性意义(P>0.05),伴随着SIRT1表达增加,FOXO1胞核阳性率明显降低(P<0.01)。结论热量限制诱导了大鼠胰岛B细胞SIRT1蛋白高表达;SIRT1可能通过抑制FOXO1活性而调控胰岛B细胞的衰老,有利于2型糖尿病的防治。     

D-半乳糖引起人正常二倍体细胞衰老的机制

目的 研究D-半乳糖处理后引起人正常二倍体细胞衰老的机制.方法 MTT法检测细胞存活率,衰老相关的β-半乳糖苷酶染色鉴定衰老细胞,流式细胞术检测细胞内活性氧自由基水平,免疫印迹法检测衰老相关蛋白的表达.结果 D-半乳糖处理人胚胎肺细胞和肝细胞,均能抑制细胞的增殖.被处理的细胞衰老相关的β-半乳糖苷酶染为蓝色,细胞内活性氧自由基水平明显升高,衰老信号通路相关蛋白p53、p21、caviolin-1的表达均升高.结论 D-半乳糖引起人正常二倍体细胞出现典型的细胞衰老表型,可以作为衰老的可靠模型.     

睾酮对心脏老化过程中心肌纤维化的干预研究

目的观察睾酮对心脏老化过程中心肌纤维化的干预效应。方法差速贴壁法培养雄性昆明白乳鼠心肌成纤维细胞,并分为4组:A组(培养液)、B组(60 μmol/L H_2O_2)、C组(30 nmol/L 睾酮+B组)、D组(氟他胺1μmol/L+C组)。用β半乳糖苷酶染色检测细胞的阳性率,MTT法检测细胞增殖能力,流式细胞仪分析细胞周期,二氯荧光黄荧光显色检测细胞内活性氧(ROs)。α平滑肌肌动蛋白(α-SMA)免疫化学染色反应细胞的表型转化,RT-PCR法检测转化生长因子β1(TGF-β1)mRNA、P16 mRNA和cyclin D1 mRNA的表达。结果与A组比较.B组β-半乳糖苷酶染色阳性细胞增加,ROS水平增加,P16 mRNA、cyclin D1 mRNA、TGF-β1 mRNA表达上调,细胞增殖能力明显下降,G_0/G_1期细胞比例增多,同时α-SMA免疫组织化学染色出现明显强阳性;与B组比较,C组上述各项指标下降;与C组比较,D组能部分阻断睾酮的各种保护作用。结论睾酮通过受体机制干预氧化应激诱导的心肌成纤维细胞的衰老,这可能是睾酮抗心脏老化过程中心肌纤维化的机制之一。     

黄芪多糖对衰老HDFβ-半乳糖苷酶活性影响的实验研究

目的 探讨黄芪多糖（APS）对衰老人胚肺二倍体成纤维细胞（HDF）衰老相关β-半乳糖苷酶（SAβ-gal）活性的影响.方法 MTT法测细胞活力;免疫组化法测衰老相关β-半乳糖苷酶染色阳性细胞数.结果 黄芪多糖可以增强细胞活力,降低SAβ-gal染色阳性细胞数.结论 黄芪多糖延缓HDF细胞衰老的机制之一可能是减少了SAβ-gal的表达.     

虫草提取物对高糖诱导的脐静脉内皮细胞损伤模型的保护作用

目的研究虫草提取物对人脐静脉内皮细胞损伤模型的影响,探讨其保护内皮功能的机制。方法原代培养人脐静脉内皮细胞,高糖(40mmol/L)孵育,建立细胞损伤模型。实验分组:空白组、高糖组、冬虫夏草组、蛹虫草组。MTT法检测细胞增殖;SA-β-半乳糖苷酶(SA-β-gal)染色法检测SA-β-gal染色阳性率;流式细胞术测定细胞周期及细胞内活性氧;实时荧光定量PCR检测衰老相关的p16、p21、沉默信息调节因子1(SIRT1)、Bcl-2mRNA表达水平。结果与空白组比较,高糖组细胞增殖明显下降,细胞内活性氧增加(P<0.05)。与高糖组比较,蛹虫草组及冬虫夏草组细胞增殖增加,S期细胞明显增多,SIRT1mRNA水平显著升高,细胞内活性氧和p21mRNA水平均显著降低(P<0.05)。结论虫草提取物对损伤内皮具有保护作用,其机制可能与促进SIRT1mRNA表达,减轻细胞氧化应激损伤,抑制p21mRNA表达,促进内皮细胞生长增殖有关。     

白藜芦醇通过抑制细胞凋亡延缓内皮细胞衰老

目的 探讨SIRT1在内皮细胞自然衰老过程中的变化和作用机制。方法 连续培养传代人脐静脉内皮细胞（HUVECs）38代，选取第1、5、10、15、20、25、30和35代细胞做Western blot检测内皮细胞自然衰老过程中SIRT1蛋白含量变化以及Annexin V-FITC法测定内皮细胞凋亡水平变化。选取第25代细胞，给予SIRT1激动剂白藜芦醇（30 μmol/L）干预，β-半乳糖苷酶染色法检测内皮细胞的衰老程度以及Annexin V-FITC法测定内皮细胞凋亡水平。结果 随着代数增加，内皮细胞上的SIRT1蛋白表达逐渐降低（P<0.01），内皮细胞凋亡率逐渐升高（P<0.01）；给予第25代细胞白藜芦醇干预后，内皮细胞上的SIRT1表达升高（P<0.01），β-半乳糖苷酶阳性细胞率降低（P<0.01），凋亡率也降低（P<0.05）。结论 内皮细胞自然衰老过程中，SIRT1的表达会降低；给予白藜芦醇干预后，能逆转内皮细胞的衰老，其作用机制可能与SIRT1降低了内皮细胞凋亡水平有关。     

Three layer functional model and energy exchange concept of aging process

Relying on a certain degree of abstraction, we can propose that no particular distinction exists between animate or living matter and inanimate matter. While focusing attention on some specifics, the dividing line between the two can be drawn. The most apparent distinction is in the level of structural and functional organization with the dissimilar streams of ‘energy flow’ between the observed entity and the surrounding environment. In essence, living matter is created from inanimate matter which is organized to contain internal intense energy processes and maintain lower intensity energy exchange processes with the environment. Taking internal and external energy processes into account, we contend in this paper that living matter can be referred to as matter of dissipative structure, with this structure assumed to be a common quality of all living creatures and living matter in general. Interruption of internal energy conversion processes and terminating the controlled energy exchange with the environment leads to degeneration of dissipative structure and reduction of the same to inanimate matter, (gas, liquid and/or solid inanimate substances), and ultimately what can be called ‘death.’ This concept of what we call dissipative nature can be extended from living organisms to social groups of animals, to mankind. An analogy based on the organization of matter provides a basis for a functional model of living entities. The models relies on the parallels among the three central structures of any cell (nucleus, cytoplasm and outer membrane) and the human body (central organs, body fluids along with the connective tissues, and external skin integument). This three-part structural organization may be observed almost universally in nature. It can be observed from the atomic structure to the planetary and intergalactic organizations. This similarity is corroborated by the membrane theory applied to living organisms. According to the energy nature of living matter and the proposed functional model, the decreased integrity of a human body's external envelope membrane is a first cause of the structural degradation and aging of the entire organism. The aging process than progresses externally to internally, as in single cell organisms, suggesting that much of the efforts towards the restoration and maintenance of the mechanisms responsible for structural development should be focused accordingly, on the membrane, i.e., the skin. Numerous reports indicate that all parts of the human body, like: bones, blood with blood vessels, muscles, skin, and so on, have some ability for restoration. Therefore, actual revival of not only aging tissue of the human body's membrane, but the entire human body enclosed within, with all internal organs, might be expected. We assess several aging theories within the context of our model and provide suggestions on how to activate the body's own anti-aging mechanisms and increase longevity. This paper presents some analogies and some distinctions that exist between the living dissipative structure matter and inanimate matter, discusses the aging process and proposes certain aging reversal solutions.     

Unusual responses of nocturnal pineal melatonin synthesis and secretion to swimming: Attempts to define mechanisms

Abstract: The effect of swimming at night on rat pineal melatonin synthesis was compared with that of light exposure at night. Rats were forced to swim at 0030 hr (lights out at 2000 hr) and sacrificed by decapitation 15 and 30 min later, immediately after swimming. Other groups of animals were exposed to white light (650μW/cm²) for 15 and 30 min at same time. Swimming caused a rapid and highly significant drop in the melatonin content in the pineal gland; however, the activity of N-acetyltransferase (NAT), the supposed rate limiting enzyme in the melatonin production, was not changed. Despite the drop in pineal melatonin levels, serum concentrations of the indole remained elevated in the rats that swam. In contrast, melatonin levels in the pineal and serum of light exposed rats fell precipitously, accompanied by a significant suppression of NAT activity. Since we anticipated that the strenuous exercise associated with swimming may induce release of artrial natriuretic peptide (ANP) from the heart, which in turn could cause the release of pineal melatonin, in a second study we injected physiological saline intravenously to stretch the cardiac muscle and release ANP. Three milliliters of normal saline was injected during the day into the jugular vein of anesthetized rats that were pretreated with isoproterenol to stimulate pineal melatonin production. Animals were killed 15 min after the saline injection, and pineal NAT activity and pineal melatonin levels were measured. The saline injections caused no alteration in the elevated levels of either NAT or melatonin. These data suggest that the disparity in pineal NAT activity (which was high) and pineal melatonin (which was low), in animals swum at night, may not be caused by ANP which is released during strenuous exercise such as swimming.     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep

Abstract: Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status—the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic nuclei activity to allow endogenous melatonin to normally synchronize reproductive activity to the optimal time of year. The Romney Marsh sheep is particularly explored as an experimental model. It is suggested that the on/off activity of seasonal reproduction may be a robust mechanism able to be predictably manipulated by the judicious use of the light/dark cycle and exogenous melatonin, but firmly based on circadian principles.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.