桑叶黄酮对腺嘌呤诱导大鼠高尿酸血症肾损伤的防治作用

本文研究了桑叶黄酮(mulberry leaf flavonoids,MLF)对腺嘌呤诱导大鼠高尿酸血症、肾损伤的防治作用.采用腺嘌呤灌胃法诱导SD大鼠制备高尿酸血症和肾损伤模型,MLF预防治疗3w,测定与高尿酸血症和肾衰相关的各项组织器官和血液生化指标.结果显示桑叶总黄酮可显著降低血清尿酸水平,与别嘌醇的降尿酸效果相当;并能显著降低尿酸氮、肌酐、丙二醛、甘油三酯、游离脂肪酸水平和肝脏系数、肾脏系数.上述结果表明桑叶总黄酮有干预腺嘌呤诱导高尿酸血症和肾损伤的作用.     

不同造模剂诱导大鼠高尿酸血症模型的可行性比较

目的比较三种高尿酸血症大鼠模型的可行性。方法实验大鼠随机分为三个造模组和对照组。造模组分别予5%氧嗪酸钾（5%OA）饲料、10%酵母粉（10%YE）饲料、10%酵母粉＋2%氧嗪酸钾（10%YE＋2%OA）饲料饲养3周后予普通饲料饲养1周,对照组予普通饲料。各周留取大鼠血、尿标本,检测尿酸、肌酐、尿素氮、白蛋白、甘油三酯、胆固醇等指标的变化。结果与对照组相比,5%OA组血尿酸在各周均升高（P〈0.05）;10%YE组血尿酸仅在第2周升高（P〈0.05）;10%YE＋2%OA组血尿酸在第1、2周升高（P〈0.05）,第3周下降至正常。造模组与对照组的体重、血清肌酐、血清尿素氮、血清白蛋白水平无差异。结论 5%OA模型可形成较稳定的高尿酸血症状态,10%YE模型难以达到高尿酸血症状态,10%YE＋2%OA模型血尿酸水平欠稳定。     

芹菜素-钐配合物的合成及其抗小鼠高尿酸血症研究北大核心CSCD

秉承中药配位化学理论,以具有一定抗炎、抗痛风活性的芹菜素(AP)为配体,以稀土金属钐(Ⅲ)离子为配位中心,设计合成芹菜素-钐配合物(AP-Sm),以期提高抗高尿酸血症活性。采用紫外(UV)、红外(IR)、氢核磁共振(1H NMR)、电导法、差热-热重分析(TG-DTA)等技术对配合物的化学结构进行表征。考察配合物对酵母浸粉联合氧嗪酸钾诱导的高尿酸血症小鼠模型中尿酸、黄嘌呤氧化酶及超氧阴离子水平的影响。结果表明,芹菜素与钐(Ⅲ)离子配位生成了配合物,配合物组成式为:Sm(C_(15)H_9O_5)_3. 2H_2O。芹菜素A环的5-OH和C环的4位C=O与钐(Ⅲ)离子形成了配合物,且芹菜素与钐(Ⅲ)离子的配位比为3。抗高尿酸血症活性研究发现,芹菜素-钐配合物对高尿酸血症小鼠黄嘌呤氧化酶的抑制作用、清除超氧阴离子能力、降低血清尿酸水平及促进尿酸排泄能力均优于芹菜素。综上说明芹菜素与钐(Ⅲ)离子配位后,所得配合物抗高尿酸血症活性增强。     

番茄皂苷A对小鼠血脂及肝脏脂肪的作用

该研究以ApoE基因缺陷小鼠和高脂饲料诱导的高血脂症模型小鼠为对象,采用药理学方法研究了番茄皂苷A对血脂及肝脏脂肪的调节作用。在ApoE基因缺陷小鼠和高脂饲料诱导的高血脂症模型小鼠中,通过灌胃给予番茄皂苷A:取血,测定血清中总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDLC)、低密度脂蛋白胆固醇(LDLC)、谷丙转氨酶(ALT)、谷草转氨酶(AST)、尿素氮(BUN)、肌酐(Cr)、葡萄糖(Glu)的含量和活性;处死小鼠后,取肝脏称重,计算肝脏指数;精确称取一部分肝脏,测定肝脏脂质的含量。结果表明:番茄皂苷A对ApoE基因缺陷小鼠可以降低血清TC、HDLC、LDLC的含量,对ALT、AST、BUN、Cr、Glu没有影响,说明番茄皂苷A可以降低ApoE基因缺陷小鼠血中胆固醇含量,对血糖没有影响,对肝肾功能无影响;对高脂饲料诱导的高血脂症模型小鼠,可以降低血清TC、HDLC的含量,可以降低肝脏TC的含量,对ALT、AST、BUN、Cr、Glu没有影响,说明番茄皂苷A可以改善高脂饲料诱导的高血脂症模型小鼠的脂质代谢,且对肝肾功能无影响。该研究结果表明番茄皂苷A具有一定的降低胆固醇的作用,且不影响肝肾功能。     

铁观音茶水提物对小鼠高尿酸血症的缓解作用

近年来,高尿酸血症（hyperuricemia,HUA）在人群中频发,危害性强,并发症多。为了探究日常饮品--半发酵茶铁观音茶水对于缓解HUA是否具有辅助作用,以小鼠为实验对象,采用氧嗪酸钾和次黄嘌呤联合法构建小鼠高尿酸血症模型,21只模型鼠随机分为模型组、铁观音茶水提物组、阳性药物组,7只非模型鼠作为对照。做不同处理2周后,取小鼠血清及肾、肝、小肠。观察各器官病理变化,从细胞层面鉴定铁观音茶水提物对高尿酸血症小鼠各脏器的影响;测定与HUA相关度较高的生化指标：血清尿酸（uric acid,UA）浓度、肝黄嘌呤氧化酶（xanthine oxidase,XOD）活力,以明确造模是否成功以及判断铁观音茶水提物对HUA是否具有缓解作用;利用qRT-PCR检测尿酸合成和排泄相关基因的mRNA表达水平,并利用Western blot检测肝XOD蛋白的表达水平,以从分子层面明确铁观音茶水提物对HUA的影响。病理切片显示,相比于阳性药物组,铁观音茶水提物组小鼠的肾和肝损害程度较轻;生化指标测定结果显示,铁观音茶水提物可降低血清尿酸水平,并且抑制XOD活性;从分子层面可以看出,铁观音茶水提物显著升高了尿酸重吸收转运体尿酸转运蛋白1(uric acid transporter 1,URAT1)和有机阴离子转运蛋白3(organic anion transporter 3,OAT3)的mRNA表达水平（P<0.05）,显著降低了葡萄糖转运子9（glucose transporter 9,GLUT9）和有机阴离子转运蛋白1(organic anion transporter 1,OAT1)的表达水平（P<0.05）。虽然qRT-PCR和Western blot提示,XOD的mRNA和蛋白质的表达水平升高,但尿酸生成量却下降,推测可能是铁观音茶水提物中的某种成分使得无催化活性的XOD蛋白表达增加进而对XOD基因的转录表达造成一种正反馈。研究提示,铁观音茶水提物对小鼠高尿酸血症具有缓解作用,其缓解高尿酸血症的作用与抑制XOD活性、干预尿酸生成过程和刺激或抑制相关阴离子转运体mRNA的表达相关。     

三七总皂苷对大鼠骨髓间充质干细胞凋亡的抑制作用北大核心CSCD

本文旨在研究三七总皂苷(total saponins of Panax notoginseng,t PNS)对二氯化钴(CoCl_2)诱导的大鼠骨髓间充质干细胞(rat bone marrow mesenchymal stem cells,r BMSCs)凋亡的抑制作用及机制。采用密度梯度离心法分离SD大鼠BMSCs。不同浓度t PNS(1、10和100μg/m L)处理r BMSCs 48 h后,行流式细胞术检测细胞增殖(Ed U法)和细胞周期。300μmol CoCl_2孵育细胞24 h诱导凋亡,在CoCl_2处理的同时加入不同浓度t PNS(1、10和100μg/m L)。Annexin V-FITC/PI染色后,用流式细胞仪检测细胞凋亡率;罗丹明123染色后,在荧光显微镜下观察线粒体膜电位改变;q RT-PCR检测细胞Bcl-2家族的基因表达。结果显示,t PNS各浓度组细胞增殖率均较对照组升高,100μg/m L t PNS组G2+S期细胞百分比较对照组升高。与对照组相比,CoCl_2组细胞凋亡率增加14.2%,而t PNS三个浓度组细胞凋亡率分别较CoCl_2组减少14.4%、12.8%和13.9%(均P<0.01)。与对照组相比,CoCl_2组线粒体膜电位明显降低,而t PNS各浓度组膜电位降低程度明显低于CoCl_2组。t PNS各浓度组的Bcl-2和Bcl-xl m RNA表达均高于CoCl_2组(均P<0.05);10和100μg/m L t PNS组的Bax/Bcl-2比值较CoCl_2组显著降低。以上结果提示,t PNS对CoCl_2诱导的r BMSCs凋亡有抑制作用,其机制是通过提高细胞线粒体膜电位,上调抗凋亡基因Bcl-2和Bcl-xl的表达,降低Bax/Bcl-2比值而实现的。     

蕨菜乙醇提取物降尿酸作用机理及肾保护作用研究北大核心CSCD

为研究蕨菜乙醇提取物降尿酸作用机理及其肾保护作用,将蕨菜乙醇提取物灌胃模型小鼠1周,于给药第3 d,氧嗪酸钾灌胃复制高尿酸血症小鼠模型,检测血清尿酸水平、血及肝脏黄嘌呤氧化酶活性,探讨其治疗高尿酸血症作用机理;蕨菜乙醇提取物灌胃模型小鼠1周,检测血Cr与BNU、肾组织NO与ET水平、肾组织形态学,考察其肾保护作用。结果发现蕨菜乙醇提取物可显著降低小鼠血清尿酸水平,对小鼠血及肝脏黄嘌呤氧化酶活性无显著影响,显著降低血Cr、血BNU、肾组织ET水平,升高肾组织NO水平,肾组织形态学正常。结果表明蕨菜乙醇提取物具有降尿酸及肾保护作用,其降尿酸作用机制不在影响黄嘌呤氧化酶活性,确切的作用机制还有待于进一步研究。     

一种高尿酸血症大鼠模型诱导方法的改良和效果评价研究

目的:探索短期内诱导高尿酸血症大鼠模型的有效方法,并对模型效果进行评价。方法:雄性SD大鼠随机分为对照组(CT组,6只)和5个模型组(M1-M5组),每组8只; M1组(每天酵母膏10 g/kg+腺嘌呤100 mg/kg2次灌胃,于模型诱导的第7日1次性腹腔注射氧嗪酸钾300 mg/kg)、M2组(每天酵母膏10 g/kg+腺嘌呤100 mg/kg灌胃2次,于模型诱导第1、3、7日每天腹腔注射1次氧嗪酸钾300 mg/kg)、M3组(每天酵母膏10 g/kg+腺嘌呤100 mg/kg灌胃2次,每天腹腔注射1次氧嗪酸钾300 mg/kg)、M4组(每天酵母膏20 g/kg+腺嘌呤100 mg/kg灌胃2次,每天腹腔注射1次氧嗪酸钾300 mg/kg)、M5组(每天酵母膏30 g/kg+腺嘌呤100 mg/kg灌胃2次,每天腹腔注射1次氧嗪酸钾300 mg/kg)、CT组(5个模型组按相同的时间、体重计算等体积灌胃和腹腔注射生理盐水),造模7 d;分别在造模结束时和2周后采集24 h尿样和血样检测尿酸、肌酐水平,取肾脏和胃称重,观察肾脏病理变化。结果:与CT组相比,造模结束后,所有模型组大...     

藏药菥蓂中黑芥子苷对黄嘌呤致小鼠高尿酸作用的研究北大核心CSCD

采用黄嘌呤致小鼠高尿酸模型,将昆明种小鼠随机分为模型组、空白对照组、阳性组、未灭活水提液(WMHSTY)组、灭活水提液(MHSTY)组、醇提液(CTY)组和水提醇沉浓缩液(STCCNSY)组并分别给药,以提取液对尿酸降低程度与提取液中黑芥子苷含量的关系阐明黑芥子苷与菥蓂治疗痛风作用的关系。结果,MHSTY和WMHSTY对黄嘌呤致小鼠高尿酸模型有显著的降低尿酸作用,两者间无明显差异,但黑芥子苷含量差异显著;CTY中黑芥子苷含量最高,但对本模型无明显作用;STCCNSY中无法检测出黑芥子苷,但对本模型有极显著作用。表明,藏药菥蓂中黑芥子苷的含量与菥蓂对黄嘌呤致小鼠高尿酸模型的作用无明显关系。     

齿孔酸对高尿酸血症黄嘌呤氧化酶活性的影响

采用紫外分光光度法检测齿孔酸在体外对黄嘌呤氧化酶的作用,并进行动力学研究探讨其作用机制;采用酵母联合氧嗪酸钾诱导高尿酸血症小鼠模型,观察齿孔酸对高尿酸血症小鼠血清尿酸水平、血清黄嘌呤氧化酶活性、肝脏黄嘌呤氧化酶活性及血糖血脂的影响。研究发现,齿孔酸体在外能抑制黄嘌呤氧化酶活性,降低高尿酸血症小鼠血清尿酸水平、血清黄嘌呤氧化酶活性、肝脏黄嘌呤氧化酶活性,同时明显降低空腹血糖、总胆固醇、甘油三酯、低密度脂蛋白胆固醇水平,升高高密度脂蛋白胆固醇水平,提高口服糖耐受量。结果表明,齿孔酸是黄嘌呤氧化酶竞争性抑制剂,还能缓解高尿酸血症小鼠糖脂代谢紊乱,对高尿酸血症及痛风的防治具有潜在意义。     

齿孔酸对高尿酸血症黄嘌呤氧化酶活性的影响

采用紫外分光光度法检测齿孔酸在体外对黄嘌呤氧化酶的作用,并进行动力学研究探讨其作用机制;采用酵母联合氧嗪酸钾诱导高尿酸血症小鼠模型,观察齿孔酸对高尿酸血症小鼠血清尿酸水平、血清黄嘌呤氧化酶活性、肝脏黄嘌呤氧化酶活性及血糖血脂的影响。研究发现,齿孔酸体在外能抑制黄嘌呤氧化酶活性,降低高尿酸血症小鼠血清尿酸水平、血清黄嘌呤氧化酶活性、肝脏黄嘌呤氧化酶活性,同时明显降低空腹血糖、总胆固醇、甘油三酯、低密度脂蛋白胆固醇水平,升高高密度脂蛋白胆固醇水平,提高口服糖耐受量。结果表明,齿孔酸是黄嘌呤氧化酶竞争性抑制剂,还能缓解高尿酸血症小鼠糖脂代谢紊乱,对高尿酸血症及痛风的防治具有潜在意义。     

龙牙楤木总皂苷含量测定及其抗炎镇痛活性评价

建立了一种龙牙楤木中总皂苷的含量测定方法,比较了龙牙楤木根皮和茎皮中总皂苷含量,并研究了龙牙愡木的抗炎镇痛作用。采用超声辅助提取,用紫外-可见分光光度法,以齐墩果酸为对照品建立标准曲线;以5%香草醛-冰醋酸为显色剂,检测波长550nm,用比色法测定总皂苷含量。结果显示所建立的方法稳定可靠,龙牙楤木不同部位皂苷含量差异较大,根皮总皂苷含量为43.50mg/g,而茎皮为24.38mg/g。总皂苷在0.02~0.10mg/mL(R~2=0.999 6)质量浓度范围内呈良好线性关系,根皮和茎皮的平均回收率分别为100.12%(RSD=1.10%)和99.84%(RSD=1.77%)。采用醋酸致小鼠扭体试验和耳廓肿胀试验研究龙牙楤木总皂苷抗炎镇痛活性,结果表明龙牙楤木总皂苷能显著减轻醋酸对试验小鼠内脏所致的疼痛(P<0.05)和降低由二甲苯所致实验小鼠耳廓的肿胀程度(P<0.05),显示出较强的抗炎镇痛作用,且根皮的作用效果比茎皮好。龙牙愡木抗炎镇痛活性可能与其总皂苷含量呈正相关。建立的总皂苷含量测定方法简便、准确、重现性好,可作为龙牙楤木根皮与茎皮中总皂苷的含量测定方法。     

Physiological effects of peracetic acid on hydroponic tomato plants

Peracetic acid (PAA) has potential as a disinfectant of low environmental impact for glasshouse hydroponic systems and other horticultural applications, but can have phytotoxic effects. This study examined the physiological effects of PAA when applied hydroponically to tomato plants. Plants treated with 0.5–5 μg ml^?1 PAA over several weeks exhibited a reduction in size of all vegetative organs. During the first 2 h of PAA treatment, plants also exhibited a transient wilting, with increased stomatal resistance, and reductions in transpiration and CO2 assimilation. The toxicity of PAA to roots was apparent from increased leakage of root electrolytes, reduced oxygen consumption, death of root tips, and collapse of the internal tissues. The shrivelling of PAA‐treated roots resulted from loss of water to the shoot in the transpiration stream, as the effect could be eliminated by removal of the shoot and sealing of the cut stump. HgCl2, a reagent known to reduce the hydraulic conductivity of root systems, caused the same root shrivelling effects as PAA. Long‐term growth of PAA‐treated plants was dependent upon the replacement of taproot systems by adventitious roots, which, initially at least, displayed greater tolerance of PAA. In aqueous solution, PAA exists in equilibrium with H2O2 and acetic acid, both of which were individually toxic, but acetic acid exhibited a syndrome of effects distinct from those of PAA, while the effects of H2O2 paralleled those of PAA more closely, suggesting that oxidative rather than acidic mechanisms were primarily responsible for the phytotoxicity of PAA solutions.     

Urinary excretion of uric acid,allantoin, and 8-OH-Deoxyguanosine in uricase-knockout mice

ABSTRACT

Although uricase-knockout (Uox KO) mice are reported to develop uric acid (UA) nephropathy, those that mature without severe nephropathy could be useful for research into purine metabolism in humans. In this study, we measured the urinary excretion of creatinine, UA, allantoin, and 8-hydroxy-2′-deoxyguanosine (8-OHdG) collected from Uox KO mice housed in metabolic cages. UA and allantoin were determined using liquid chromatography–mass spectrometry and creatinine and 8-OHdG were measured with a commercial kit. Uox KO mice excreted significantly higher levels of UA than wild-type mice (C57BL/6), while the excretion of allantoin was significantly lower. Urinary allantoin was detected in Uox KO mice despite a lack of uricase, which is the same as in humans. In contrast to the elevated levels of UA, the daily excretion of 8-OHdG, an oxidative stress marker, was lower in Uox KO mice. UA is thought to act as an anti-oxidizing agent in humans; thus, these results show that Uox KO mice are potential animal models for research into human purine metabolism.     

Effect of phytic acid on postprandial serum uric acid level in healthy volunteers: a randomized,double-blind,crossover study

Abstract

Phytic acid, a constituent of various plants, has been related to health benefits. Phytic acid has been shown to inhibit purine nucleotide metabolism in vitro and suppress elevation of plasma uric acid levels after purine administration in animal models. This study investigated the effect of phytic acid on postprandial serum uric acid (SUA) in humans. This randomized, double-blind, crossover design study included 48 healthy subjects with normal fasting SUA. Subjects consumed a control drink and a phytic acid drink with purine-rich food, and serum and urine uric acid levels were measured for 360?min after purine loading. Phytic acid lowered the incremental area under the curve (0–360?min) and incremental maximum concentration of SUA after purine loading (p?<?0.05); tended to lower cumulative urinary uric acid excretion (0–360?min) after purine loading (p?<?0.10); and suppressed postprandial SUA in this clinical study. Altogether, our findings suggest that phytic acid may play a beneficial role in controlling postprandial SUA.     

5-氨基乙酰丙酸对NaCl胁迫下番茄幼苗光合特性的影响

为探讨5-氨基乙酰丙酸（ALA）对NaCl胁迫下番茄光合特性的调控作用,以‘金鹏一号’番茄幼苗为试材,研究叶面喷施50 mg·L^-1或根施10 mg·L^-1 ALA对100 mmol·L^-1 NaCl胁迫下番茄幼苗光合及叶绿素荧光参数的影响.结果表明： NaCl胁迫下,番茄幼苗光合气体交换参数（净光合速率P_n、气孔导度g_s、胞间CO₂浓度C_i、蒸腾速率T_r）及叶绿素荧光参数（实际光化学量子产量F_v′/F_m′、F_m′、PSⅡ反应中心实际光化学效率Φ_PSⅡ、表观光合电子传递效率ETR、光化学淬灭q_P、光化学反应Pc）均显著降低,根施或叶施ALA均可以提高NaCl胁迫下番茄叶片的光合能力,但两种处理方式之间存在一定差异.叶面喷施50 mg·L^-1ALA或根施10 mg·L^-1ALA处理均显著提高了番茄叶片P_n、T_r、g_s和C_i,提高了水分利用效率（WUE）,显著增加了NaCl胁迫下叶片的最大净光合速率,减轻了光抑制.根施ALA对叶绿素含量的作用效果较好,而叶施ALA对光合参数的作用效果较好,两处理叶绿素荧光参数差异不显著.叶面喷施或根施ALA可以提高番茄幼苗的耐盐性,其调控作用与促进叶绿素合成与稳定、维持正常气孔开闭、降低气孔限制,进而提高NaCl胁迫下番茄叶片的光合能力和PSⅡ光化学效率有关.
     

Immunocytolocalization of 1-aminocyclopropane-1-carboxylic acid oxidase in tomato and apple fruit

The subcellular localization of 1-aminocyclopropane-1-carboxylic acid oxidase (ACC oxidase), an enzyme involved in the biosynthesis of ethylene, has been studied in ripening fruits of tomato (Lycopersicum esculentum Mill.). Two types of antibody have been raised against (i) a synthetic peptide derived from the reconstructed pTOM13 clone (pRC13), a tomato cDNA encoding ACC oxidase, and considered as a suitable epitope by secondary-structure predictions; and (ii) a fusion protein overproduced in Escherichia coli expressing the pRC13 cDNA. Immunoblot analysis showed that, when purified by antigen affinity chromatography, both types of antibody recognized a single band corresponding to ACC oxidase. Superimposition of Calcofluor white with immunofluorescence labeling, analysed by optical microscopy, indicated that ACC oxidase is located at the cell wall in the pericarp of breaker tomato and climacteric apple (Malus × domestica Borkh.) fruit. The apoplasmic location of the enzyme was also demonstrated by the observation of immunogold-labeled antibodies in this region by both optical and electron microscopy. Transgenic tomato fruits in which ACC-oxidase gene expression was inhibited by an antisense gene exhibited a considerable reduction of labeling. Immunocytological controls made with pre-immune serum or with antibodies pre-absorbed on their corresponding antigens gave no staining. The discrepancy between these findings and the targeting of the protein predicted from sequences of ACC-oxidase cDNA clones isolated so far is discussed.