D-半乳糖亚急性中毒大鼠拟衰老生理生化改变

目的　D 半乳糖皮下注射致Wistar大鼠亚急性衰老模型 ,观察大鼠衰老指标的变化。方法　 2 0只雄性大鼠随机分为 2组 ,每组 10只。对照组每日一次皮下注射生理盐水 10ml kg,衰老模型组每日一次皮下注射D 半乳糖 4 8mg kg。各组大鼠均连续给药 4 2d ,采血后分别测定各项衰老指标。结果　与对照组比较 ,衰老模型组体重增加比例降低 ,胸腺明显萎缩 ,脏器系数减少 (P <0 .0 1) ,血清中超氧化物歧化酶 (SOD)活性明显下降 (P <0 .0 1)。结论　D 半乳糖诱发的致大鼠亚急性衰老是探讨自由基衰老学说有用的实验动物造模技术。     

Effects of Aging and Advanced Glycation on Gene Expression in Cerebrum and Spleen of Mice

Objective To analyze the effects of aging or advanced glycation on gene expression in the cerebrum and spleen of female C57BL/6J mice. Methods The gene expression profile was determined by using cDNA expression arrays containing 588 cDNA. Results Aging and advanced glycation resulted in differential gene expression patterns of cerebrum and spleen compared with young mice. Among the 80 genes detected in cerebrum, 43 exhibited a change in mRNA ratios with aging or treatment. Thirty-four changes (79%) were common in aged and D-galactose treated mice, whereas the cerebrum from aged and AGE-lysine treated mice showed common changes in expression of 38 genes (88%). Of the 86 genes detected in spleen, 29 (34%) displayed an age-related decrease in expression, whereas 3 (3%) displayed an increase in expression levels with aging. Eighteen genes from the detectable genes exhibited expression changes in both cerebrum and spleen of mice. Conclusions The gene expression profiles of D-galactose and AGE-lysine treated     

鸡胚低分子提取物对D-半乳糖拟衰老小鼠线粒体DNA缺失突变的影响

目的 探讨鸡胚低分子提取物对D-半乳糖诱导的衰老小鼠线粒体DNA(mtDNA)缺失突变的影响.方法 采用D-半乳糖诱导制备衰老小鼠模型并用鸡胚低分子提取物处理.用聚合酶链反应技术和琼脂糖凝胶电泳检测mtDNA缺失片段,密度扫描技术对扩增片段进行相对定量.缺失片段构建质粒后,直接测序进行鉴定.结果 全部小鼠的肝、大脑皮质与海马组织内均存在4239 bp的mtDNA缺失片段.衰老模型鼠不同组织mtDNA缺失的相对百分含量均明显高于正常对照组(均为P%0.01),而鸡胚低分子提取物可明显降低模型鼠肝、大脑皮质与海马组织内mtDNA缺失的比例(均为P＜0.05).肝组织中mtDNA缺失的比例较大脑皮质和海马组织更高.结论 4239 bp的mtDNA缺失片段普遍存在于小鼠中,鸡胚的低分子提取物可以明显减少D-半乳糖拟衰老小鼠4239 bp的mtDNA缺失的发生.     

醛糖还原酶抑制剂AL-1576对大鼠半乳糖性白内障的防治研究

背景 糖性白内障是糖尿病的主要眼部并发症之一,研究表明醛糖还原酶(AR)活性的升高与糖尿病的慢性并发症密切相关,是抗糖性白内障药物研究的重要靶点,其研究对糖性白内障的防治具有重要意义. 目的 探讨AR抑制剂AL-1576对半乳糖性白内障的防治效果和作用机制. 方法 4～5周龄SD大鼠42只,通过喂养质量分数50％半乳糖饲料制作半乳糖性白内障模型.大鼠按照随机数字表法平均分为7个组,AL-1576预防组,早、中、晚期治疗组在喂食50％半乳糖饲料的当天及5、10、15d后开始添加质量分数0.0125％ AL-1576,另设空白对照组、模型对照组和AL-1576干预10d后撤除的早期撤药组.在裂隙灯显微镜下动态观察各组大鼠晶状体的混浊程度并进行分级,造模35 d时摘出晶状体,分别测量其干质量、湿质量,计算并比较各组晶状体含水量的变化;检测造模35 d时各组大鼠晶状体内AR活性、超氧化物歧化酶(SOD)活性以及谷胱甘肽( GSH)的含量.结果 模型对照组大鼠12只眼晶状体均为Ⅳ级混浊,AL-1576预防组12只眼晶状体均透明,早期撤药组为Ⅱ～Ⅲ级混浊,早期治疗组为Ⅱ级混浊,而中期治疗组、晚期治疗组均为Ⅲ～Ⅳ级混浊,7个组晶状体混浊的程度差异均有统计学意义(H=17.760,P=0.009).各AL-1576治疗组大鼠晶状体含水量、AR活性均比模型对照组明显降低,差异均有统计学意义(P＜0.05),但给药的时间越晚,晶状体含水量、AR活性降低的程度越小;各AL-1576治疗组大鼠晶状体SOD活性和GSH的含量明显高于模型对照组,差异均有统计学意义( P＜0.05),AL-1576预防组的升高幅度最大. 结论 在半乳糖性白内障形成的不同阶段给予AR抑制剂AL-1576可明显抑制AR的活性.AL-1576通过阻断和减轻晶状体水肿,提高晶状体的抗氧化能力,预防和延缓晶状体混浊的发生.     

Effects of in situ and systemic lindane treatment on in vivo absorption of galactose and leucine in rat jejunum

 In vivo intestinal absorption of L-leucine is significantly decreased by the presence of lindane (0.3, 0.2 and 0.1 mM) in perfusion solution (in situ lindane treatment) for 5 min. The inhibitory effect is earlier when lindane concentration is higher, and it is irreversible. There are no changes in D-galactose absorption when lindane (0.3 and 0.2 mM) is perfused for 5 min, but a significant decrease is observed if pesticide is perfused for 10 min at 0.3 mM concentration. Subcutaneous lindane treatment at a dose of 68.76 μmol/kg over 7 days does not alter D-galactose and L-leucine absorption. In situ lindane treatment (0.3, 0.2 and 0.1 mM) induces a significant decrease in basolateral (Na⁺-K⁺)-ATPase activity. In contrast, systemic lindane treatment (s.c. injection) at doses of 34.38 and 68.76 μmol/kg over 7 days does not alter this enzyme activity, although a significant decrease is observed in rats injected s.c. with 68.76 μmol/kg lindane over 15 days. Received: 21 November 1995/accepted: 21 February 1996     

Replacement of the promoter of the yeast plasma membrane ATPase gene by a galactose-dependent promoter and its physiological consequences

Summary In order to probe the physiological role of the yeast plasma membrane ATPase we have replaced the constitutive promoter of its gene by a galactose-dependent promoter. The resulting cells stop growing on glucose medium when the preformed ATPase is diluted to 20% of normal. There is a correlation between ATPase activity and both proton efflux from the cells and amino acid transport. A large proportion of growth-arrested cells appear enlarged and with several buds containing nuclei.     

半乳糖受体介导的c-myc反义寡核苷酸对人肝癌细胞的靶向投递作用

背景与目的:c-myc反义寡核苷酸(antisenseoligodeoxynucleotide,ASODN)能抑制肝癌细胞的增殖,脂质体和腺病毒介导的c-mycASODN投递虽能显著抑制肝癌细胞的增殖,抑制荷肝癌小鼠肿瘤的生长,但这种投递缺乏靶向性;受体介导的药物投递具有高效性和靶向性的特点,已被用于基因及ASODN的靶向投递。本实验以半乳糖(galactose,Gal)-聚乙烯亚胺(polyethyleneimine,PEI)作为载体,介导c-mycASODN作用于人肝癌细胞Bel-7402,探讨c-mycASODN对Bel-7402细胞的靶向投递作用。方法:用流式细胞仪检测Bel-7402、U937细胞对荧光标记的Gal-PEI-c-myc-ASODN(简称Gal-PEI-ASODN)的摄取率及细胞内平均荧光强度;相差/荧光显微镜观察荧光标记的Gal-PEI-ASODN及c-myc-ASODN进入Bel-7402、U937、Raji细胞的形态;台盼蓝拒染法检测不同浓度Gal-PEI-ASODN对这三种细胞增殖的影响。结果:荧光标记的Gal-PEI-ASODN或ASODN与相应细胞孵育10min到4h,Gal-PEI-ASODN-Bel-7402细胞的荧光摄取率为88.25%～98.66%,细胞内平均荧光强度为38.64%～111.90%,与单纯c-mycASODN-Bel-7402细胞组、Gal-PEI-ASODN-U937细胞组相比,所有时间点的细胞荧光摄取率、胞内平均荧光强度均显著增高,经Poission分布检验,均有显著性差异(P<0.01)。相差/荧光显微镜观察到     

Impact of patient mutations on heterodimer formation and function in human galactose-1-P uridylyltransferase

Impairment of the human enzyme galactose-1-P uridylyltransferase (hGALT) results in the potentially lethal disorder, galactosemia. One of the fundamental questions with regard to this dimeric enzyme involves the possible influence of patient mutations on heterodimer formation and activity. Indeed, considering that many if not most galactosemia patients are compound heterozygotes, this is an issue of clinical as well as basic science interest. We have utilized a yeast expression system for the human enzyme to test whether each of a small number of mutations in hGALT (S135L, F171S, F171W, Q188R, N314D, and R333W) impact either heterodimer formation or function. Our results clearly demonstrate that while a majority of the alleles tested show precisely random patterns of subunit assortment, two deviate slightly but significantly from this pattern. Similarly, while some heterodimers exhibit apparent independence of subunit activity, others do not. These data not only demonstrate that common patient mutations in hGALT can influence both heterodimer formation and function in heterozygotes, they further raise the question of whether such interactions may also occur between different mutant alleles in compound heterozygotes (i.e., patients). Indeed, such influences may underlie some of the biochemical and clinical heterogeneity observed in the galactosemia patient population.     

半乳糖基多聚赖氨酸携带HSV1-TK对HepG2细胞体外效应研究

目的为肝癌的自杀基因治疗寻找新的靶向分子方法通过还原氨化法进行乳糖（Lac）与聚赖氨酸（PLL）共价连接；经Sephadex G-10枉分离纯化；以苯酚-硫酸比色法测定n值；与真核表达质粒r-pAs16Dr按比例混匀，得到GlanPLL-r-pAs16Dr基因转移系统；分别转染不同的细胞株进行体外效应研究：人肝癌细胞株HepC2、人肺癌细胞株549，观察报告基因红色荧光蛋白能否在肝细胞中表达；RT—PCR检测HSV—tk基因的表达情况；观察给予不同浓度的更昔洛韦（GCV）后随时间延长细胞改变情况，用MTT法检测GCV对不同细胞的杀伤作用。结果化学合成得到34个半乳糖基的PLL；转染后48h在HepG2可见红色荧光蛋白表达，A549细胞未见红色荧光蛋白表达；RT-PCR证实HSV—tk仅在HepG2细胞中表达：体外杀伤实验显示：经GlanPLL-r-pAs16Dr基因转移系统处理的两种细胞对GCV表现出不同的敏感性HepG2细胞对GCV很敏感，低浓度的GCV（1mg／L）处理3d．即可使细胞生长抑制率达到70．5％，A549对GCV不敏感结论半乳糖基多聚赖氨酸能够与ASGPR有效的结合，合成配体来源丰富、制备简单，适合于作为自杀基因HSV—tk肝靶向运送的导向配体。