牛磺酸对四氯化碳染毒大鼠钙稳失调的干预规律

本研究中除设立正常对照组，四氯化碳（ＣＣｌ４）对照组外，尚设立２４０ｍｍｏｌ／Ｌ牛磺酸预投组（只在染毒前给予）和２４０ｍｍｏｌ／Ｌ牛磺酸同投组（只在染毒同时给予）来对照考察８０ｍｍｏｌ／Ｌ和２４０ｍｍｏｌ／Ｌ牛磺酸双投（染毒前及染毒过程中均给予）对５００ｍｇ／ＫｇＣＣｌ４经口染毒，２次／周，持续５周实验动物的干预作用。结果如下：１．２４ｍｍｏｌ／Ｌ牛以投对Ｃａ＾２＋－Ｍｇ＾２＋－ＡＴＰａｓｅ活性有     

毒物所致肝细胞钙稳态失调规律探讨

毒物所致肝细胞钙稳态失调规律探讨周炯亮符立梧廖肇浩李芳红石世华李胜联（中山医科大学公共卫生学院，广州５１００８９）细胞钙稳态是实现细胞生理功能和保持细胞结构完整的必要条件．钙稳态依赖于钙移位酶Ｃａ２＋，Ｍｇ２＋－ＡＴＰ酶，细胞内储库（内质网，线粒体）...     

慢性氯化铝染毒对大鼠大脑皮层内钙稳态影响

目的研究铝对大鼠大脑皮层细胞内游离钙([Ca2 ]i)质量浓度的影响,探讨铝的神经毒性的机制。方法应用248.7、74.7和37.3 mg/kg AlCl3对Wistar大鼠经口灌胃染毒,分别在染毒45、75和120 d和染毒结束后30 d处死大鼠,取脑分离大脑皮层。将荧光染料Fura-2/AM与皮层细胞一起孵育,应用荧光分光光度计测定[Ca2 ]I质量浓度。应用Western Blot方法测定各组大鼠脑皮层中钙调蛋白(CaM)和钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)表达情况。结果在染毒45、75和120 d时,74.7 mg/kg剂量组大鼠[Ca2 ]i质量浓度为(273.8±91.2)(、308.0±96.9)和(453.0±90.5)nmol/L,均显著高于对照组(P<0.05);染毒120 d时,高剂量组大鼠大脑皮层[Ca2 ]i质量浓度为(445.5±68.8)nmol/L,显著高于对照组(P<0.01);染毒结束后30 d,各染毒组大鼠大脑皮层[Ca2 ]i质量浓度高于对照组大鼠,但差异无显著性(P>0.05)。染毒457、5和120 d时,各染毒组大鼠大脑皮层中CaM表达与对照组相比均减少。各染毒组大鼠大脑皮层中CaMKⅡ表达与对照组相比,在不同染毒时期内均有不同程度上升。结论AlCl3可以增加皮层神经细胞内[Ca2 ]i质量浓度,同时引起CaM表达减少和CaMKⅡ表达增加,可见铝可使神经细胞内钙稳态失调而发挥神经毒作用。     

丙烯腈染毒对大鼠肝脏钙稳态某些指标的影响

本研究观察了丙烯腈对大鼠肝脏 Ca2 - ATPase、Mg2 - ATPase、Na / K - ATPase和磷酸化酶 a( P- a)活性的影响 ,探讨其对大鼠肝脏钙稳态的影响。结果表明 ,随着染毒剂量的增大和染毒时间的延长 ,各 ATPase活性均逐渐降低 ,而 P- a的活性却逐渐升高 ( P<0 .0 1) ,其中高剂量( 5 0 mg/ kg)组的各观察时段和染毒 42天时各染毒组酶活性的变化均具有显著性意义 ( P<0 .0 5 ) ,并具有较好的剂量 -反应关系 ( P<0 .0 1)。结果提示 ,丙烯腈可影响大鼠肝脏钙稳态某些指标变化 ,并可能导致肝脏钙稳态的失调     

丙烯腈染毒双大鼠肝脏钙稳态某此指标的影响

本研究观察了丙烯腈对大鼠肝脏Ｃａ＾２＋－ＡＴＰａｓｅ、Ｍｇ＾２＋－ＡＴＰａｓｅ、ＮＡ＾＋／Ｋ＾＋－ＡＴＰａｓｅ和磷酸化酶ａ（Ｐ－ａ）活性的影响,探讨其对大鼠肝脏钙稳态的影响。结果表明,随着染毒剂量的增大和染毒时间的延长,各ＡＴＰａｓｅ活性均逐渐降低,而Ｐ－ａ的活性却逐渐升高（Ｐ〈０．０１）。其中高剂量（５０ｍｇ／ｋｇ）组的各观察时段和染毒４２天时各染毒组酶活性的变化均具有显著性意义（Ｐ〈０．０５）     

牛磺酸对四氯化碳所致肝损伤保护作用的探讨

用两种动物模型探讨了Ｔａｕ对ＣＣｌ４所致大鼠肝损伤的保护作用及可能机理。结果表明，用５００ｍｇ／ｋｇＣＣｌ４两次染毒导致大鼠肝脏中ＧＳＨ、Ｐ－ＳＨ和ＭＤＡ含量的显著增加；血清中ＡＬＴ、ＧＣＡ水平明显升高。在Ｔａｕ保护组，这些指标的含量均有较明显下降。在模型Ⅱ中，先用Ｔａｕ保护一周，然后再用ＣＣｌ４染毒，给予或不再给予Ｔａｕ保护。结果表明Ｔａｕ对肝脏保护作用更加显著。实验结果提示：ＣＣｌ４引起了明显的肝损伤，０．５％和１．５％Ｔａｕ均有一定的治疗和预防ＣＣｌ４致肝损伤的效果，Ｔａｕ的作用机制可能是作为自由基捕捉剂和抗氧化剂以拮抗ＣＣｌ４在体内代谢产生的自由基及其引发的脂质过氧化作用。     

化学毒物致细胞内钙稳态失调研究的某些进展

近十几年来,从分子水平上探讨化学毒物致细胞损伤机理的研究很多,概括起来细胞损伤的主要机理包括:共价结合、自由基和脂质过氧化以及细胞内钙稳态的失调等,特别是后者尤为广大学者所关注.随着研究的日益深入,越来越多的实验表明,细胞内钙稳态的失调在细胞中毒性损伤过程中起着十分重要的作用。无疑,这方面的研究将有助于从分子水平上更加深入地认识化学中毒的生化机理.本文拟就近年来有关化学毒物致细胞内钙稳态失调研究的若干进展作一简介.     

牛磺酸对大鼠心肌损伤时心肌细胞核钙转运功能异常的保护作用

目的观察异丙肾上腺素 (ISO)致大鼠心肌缺血损伤时心肌细胞核钙转运功能的异常变化及牛磺酸对其影响。方法给Wister大鼠皮下注射5mg·kg-1ISO液 ,造成心肌缺血损伤模型。超速离心分离纯化心肌细胞核。酶学方法鉴定核纯度和测定核膜Ca 2 _ATP酶活性 ,同位素法观测核钙的摄取。结果与正常对照组比较 ,心肌缺血组 (实验组 )心肌细胞核膜钙依赖性ATPase活性降低18.1 % (P<0.05) ,45Ca2 摄取效率也显著降低 ,其最大速度降低54.6 % ;牛磺酸保护组心肌细胞核Ca2 _ATPase活性及核45Ca2 摄取与正常对照组比较均未见显著性改变。结论牛磺酸对ISO致大鼠心肌损伤时心肌细胞核钙转运功能降低有保护作用     

中枢神经系统钙稳态失调有阿尔采末病发病机制中的作用

阿尔采末病与衰老和细胞内钙稳态失调等因素有关；ＡＤ的发病机制中多种因素可以使神经元〖Ｃａ＾２＋〗ｉ的升高可引起兴奋性毒性反应、自由基损伤、Ｔａｎ蛋白的积聚和过度磷酸化、Ａβ的毒性增大、激活Ｃａｌ－Ｐａｉｎ及诱发细胞凋亡。该文综述了最近关于钙平衡失调的假说的有关进展。     

牛磺酸对大鼠心肌缺血再灌注后肝损伤的保护作用

目的观察牛磺酸对大鼠心肌缺血再灌注肝损伤时超氧化物歧化酶（SOD）、一氧化氮（NO）含量和磷脂酶A2（PLA2）的影响。方法大鼠随机分4组（n=10）,对照组、牛磺酸低、中、高剂量组,采用大鼠冠状动脉结扎再通的方法,观察牛磺酸对大鼠心肌缺血再灌注后血清和肝组织匀浆SOD、NO和PLA2的影响。结果牛磺酸各剂量组与对照组相比,血清和肝组织匀浆SOD含量明显提高,NO含量和血清PLA2浓度明显降低。结论牛磺酸能够通过清除自由基,降低NO及自由基损伤,降低PLA2而减轻炎症反应和急性损伤,对心肌缺血再灌注肝损伤有一定的保护作用。     

牛磺酸对肝微粒体膜的保护作用研究

以四氯化碳（ＣＣｌ４，１０ｍｍｏｌ．Ｌ＾－１）与分离的大鼠肝微粒体共同温育（３７℃，１０，２０，３０，６０，１２０分钟），预先或同时加入牛磺酸（Ｔａｕｒｉｎｅ，Ｔａｕ），观察其对肝微粒体膜的保护作用，结果表明，ＣＣｌ４引起孵育体系中外源性加入的还原型谷胱甘肽（ＧＳＨ）、微粒体膜蛋白巯基（Ｐ－ＳＨ）含量降低，膜脂流动性（ＬＦＵ）降低，Ｔａｕ对此均有罗明显的保护作用；在用Ｔａｕ预孵育的实验体系中，Ｔａ     

Late preventive effects against carbon tetrachloride-induced liver necrosis of the calcium chelating agent calcion

In agreement with the hypothesis that changes in calcium homeostasis might be significant in late stages of chemically-induced liver cell injury, a calcium chelating agent, Calcion, was able to partially prevent CCl₄-induced liver necrosis observed at 24 h, when treatment was given as late as 6 or 10 h after the hepatotoxin. Calcion had minor or no effects on covalent binding of reactive metabolites to cellular components, or on lipid peroxidation or on CCl₄ levels reaching the liver. Calcion treatment of CCl₄-poisoned animals decreased CCl₄-induced calcium increases in liver and increased gluthathione levels decreased by hepatotoxin at 24 h. Calcion treatment was not able to prevent CCl₄-induced fatty liver. Calcion protective effects were body temperature dependent but they were cancelled when Calcion-treated poisoned animals were kept normothermic. Results suggest that Calcion protective effects might be linked to calcium chelation or alternatively that they might derive from decreases in body temperature.     

高血糖大鼠肝纤维肝脏氧化还原状态的影响

目的:观察高血糖对正常或伴随炎症、纤维化肝的氧化还原状态的影响。方法:将24只大鼠分为对照组、高血糖组、正常血糖 四氯化碳组、高血糖 四氯化碳组(STZ诱导高血糖,4周后用四氯化碳诱导肝纤维化),第9周处死。测量其肝组织GSH、SOD、MDA的水平。结果:未注射CCl4加高血糖组肝MDA较对照组有所增加,GSH、SOD则有一定程度的减少。CCl4组和CCl4加糖尿病组的MAD明显升高,GSH、SOD则降低,它们之间无明显差异。结论:8周的高血糖可能一定程度的改变肝脏的氧化还原状态,但这种改变不够明显。在并发肝脏炎症时,高血糖不能进一步加重肝脏的氧化打击。     

Protective effect of Vitamin D3 against lead induced hepatotoxicity,oxidative stress,immunosuppressive and calcium homeostasis disorders in rat

Lead (Pb) is an extremely poisonous, non-essential trace element and toxicity develops in humans following frequent exposure to the heavy metal in polluted environmental and occupational settings. Pb induces hepatic damage through the depletion of the antioxidant system, enhancing cellular oxidative stress and stimulation of proinflammatory cytokines. Although the antioxidant and anti-inflammatory actions of vitamin D₃ (VD₃) are well-established, a minority of studies measured the protective actions of VD₃ against Pb toxicity. Therefore, this work studied the effects of vitamin VD₃ therapy on the fundamental molecular basis underlying hepatic injury induced by chronic Pb toxicity. Twenty-four adult male rats were distributed equally into the negative controls (NC), positive controls (PC) and VD3 groups. While both the PC and VD3 groups received Pb-acetate in drinking water (1000 mg/L) for four weeks, the latter group also received intramuscular VD3 injections (1000 IU/kg; 3 days/week) simultaneously with Pb. The liver enzymes together with the serum and hepatic tissue Pb concentrations increased markedly in the PC group compared with the NC group. Pb toxicity also drastically induced hepatocyte apoptosis/necrosis, increased the hepatic tissue concentrations of malondialdehyde and the pro-inflammatory cytokines (TGF-β, IL-4 & TNF-α) as well as reduced the anti-oxidative enzymes (GSH, GPx & CAT) and the anti-inflammatory cytokine, IL-10, compared with the NC group. Pb also significantly decreased the serum concentrations of VD3 and Ca²⁺. Additionally, the hepatic expressions of VD receptor, Cyp24a1 enzyme, L-type Ca²⁺-channel, calbindin-D_28k & -D_29k, calmodulin and calmodulin-dependent protein kinase II were significantly upregulated, whereas the VD binding protein, CYP2R1 enzyme and T-type Ca²⁺-channel were markedly inhibited at the gene and protein levels following Pb intoxication. VD3 alleviated the hepatic damage, inhibited the oxidative stress and pro-inflammatory molecules as well as upregulated the anti-oxidant and anti-inflammatory markers and restored the expression of the VD/Ca²+ regulatory molecules compared with the PC group. VD3 supplementation discloses promising protective effects against Pb-induced hepatic damage, through its anti-inflammatory and antioxidant actions as well as by modulating the hepatocyte calcium homeostatic molecules.     

注射用西黄总苷对四氯化碳致大鼠慢性肝损伤的保护作用研究

目的:观察注射用西黄总苷对四氯化碳所致大鼠慢性肝功能损伤的保护作用.方法::采用皮下注射25?l4花生油溶液5 mL/kg,每周2次,共3周,造成慢性肝损伤模型.造模前3 d预先静脉注射西黄总苷及阳性对照菌栀黄注射液,每日1次,连续给药3周.于末次给药后1 h取血.测血清AST、ALT、TP及ALB,处死动物取肝脏做病理组织学检查,观测其对CCl4所致慢性肝功能损伤的保护作用.结果:西黄总苷小、中、大剂量组与模型组相比,可显著降低CCl4引起的血清AST、ALT升高,显著抑制CCl4引起的血清总蛋白(TP)和白蛋白(ALB)降低,经统计学分析,均有非常或极显著性差异(P<0.01或P<0.001).结论:注射用西黄总苷能保肝降酶,对慢性肝损伤有保护作用.     

Taurine,a possible urinary marker of liver damage: a study of taurine excretion in carbon tetrachloride-treated rats

Carbon tetrachloride (CCl₄) caused a dose-dependent increase in urinary taurine which correlated with both the histological and biochemical assessment of liver damage. The peak elevation in urinary taurine occurred within the first 48 h after dosing but there was still significant taurinuria 72 and 96 h after the intermediate dose (1 ml.kg^–1) and highest dose (2 ml.kg^–1), respectively. Levels of taurine in serum were also elevated over the 24 h period following a hepatotoxic dose (2 ml.kg^–1) of CCl₄. In contrast, although initially elevated, levels of taurine in the liver declined over the 24 h period following dosing and were significantly lower 96 h after a hepatotoxic dose of CCl₄ (2 ml.kg^–1). Male rats showed a different urinary profile for taurine than female rats after dosing with CCl₄. A reduction in food intake seemed to lower urinary taurine levels although these changes were not statistically significant. There was a significant correlation between the level of urinary taurine and the level of serum AST for individual animals given a hepatotoxic dose of CCl₄ (2 ml.kg^–1). The data presented suggest that: i) taurine is produced by the liver in response to a toxic insult and subsequent leakage from damaged cells leads to increased levels in the urine; ii) the urinary taurine level may be a useful non-invasive marker of liver damage.     

Arsenite‐induced endoplasmic reticulum‐dependent apoptosis through disturbance of calcium homeostasis in HBE cell line

Calcium (Ca²⁺) is a ubiquitous cell signal responsible for multiple fundamental cellular functions, including apoptosis. Whether the homeostasis of Ca²⁺ is involved in arsenite‐induced apoptosis remains unclear. In this study, we observed that arsenite significantly elevated the intracellular Ca²⁺ concentration in a dose‐ and time‐dependent manner. By using the Ca²⁺‐ATPase inhibitor, thapsigargin, and the inositol 1,4,5‐ trisphosphate receptors (IP3Rs) inhibitor, heparin, we further confirmed that the disturbance of endoplasmic reticulum (ER) Ca²⁺ homeostasis caused Ca²⁺ overload in the cells. Moreover, loss of ER Ca²⁺ homeostasis also led to ER stress, mitochondrial dysfunction, and NF‐κB activation. Importantly, pretreatment of cells with heparin remarkably attenuated the elevated cell apoptosis induced by arsenite, but inhibition of ER Ca²⁺ uptake with thapsigargin exacerbated arsenite‐induced cell damage significantly. Together, we demonstrated for the first time that arsenite disturbed the Ca²⁺ homeostasis in ER, which subsequently led to ER stress, mitochondrial dysfunction, and NF‐κB nuclear translocation, and thus consequently triggering cell apoptosis. Our findings indicate regulation of disrupted Ca²⁺ homeostasis in ER may be a potential strategy for prevention of arsenite toxicity. © 2015 Wiley Periodicals, Inc. Environ Toxicol 32: 197–216, 2017.     

Protective effects of magnolol against oxidized LDL-induced apoptosis in endothelial cells

Magnolol, a compound extracted from the Chinese medicinal herb Magnolia officinalis, has several biological effects. However, its protective effects against endothelial injury remain unclear. In this study, we examined whether magnolol prevents oxidized low density lipoprotein (oxLDL)-induced vascular endothelial apoptosis. Incubation of oxLDL with magnolol (2.5–20 μM) inhibited copper-induced oxidative modification via diene formation, thiobarbituric acid reactive substances (TBARS) assay and electrophoretic mobility assay. Apoptotic cell death as characterized by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) stain. We measured the production of reactive oxygen species (ROS) by using the fluorescent probe 2′,7′-dichlorofluorescein acetoxymethyl ester (DCF-AM), and observed the activity of antioxidant enzymes. Furthermore, several apoptotic signaling pathways which showed NF-κB activation, increased cytosolic calcium, alteration of mitochondrial membrane potential, cytochrome c release and activation of caspase 3 were also investigated. We demonstrated that magnolol prevented the copper-induced oxidative modification of LDL. Magnolol attenuated the oxLDL-induced ROS generation and subsequent NF-κB activation. Furthermore, intracellular calcium accumulation and subsequent mitochondrial membrane potential collapse, cytochome c release and activation of caspase 3 caused by oxLDL were also inhibited by magnolol. Our results suggest that magnolol may have clinical implications in the prevention of atherosclerotic vascular disease through decreasing the oxLDL-induced ROS production.     

牛磺酸对半乳糖胺及硫酸亚铁-抗坏血酸所致大鼠肝细胞损伤的保护作用

以半乳糖胺(Galn)和硫酸亚铁-抗坏血酸(Fe-Vit C)与原代肝细胞共同培养,制成不同的肝细胞损伤模型,用不同浓度的牛磺酸预处理,以观察其对肝细胞的保护作用,结果表明:Fe—Vit C作用60min即可引发肝细胞的脂质过氧化(LPO),使培养液中的丙二醛含量明显升高,但不造成肝细胞破坏,0.6～3mmol·L~(-1)牛磺酸可明显减轻LPO程度,而浓度为30～60mmol·L~(-1)时非但不能减少LPO,反而使乳酸脱氢酶(LDH)的释放明显升高,Galn则可造成明显的肝细胞损伤,使LDH释放,0.6～3 mmol·L~(-1)牛磺酸对于这种肝细胞损伤有一定的保护作用,而30～60 mmol·L~(-1)的牛磺酸本身则可造成正常及中毒肝细胞的损伤。