交链孢酚和交链孢酚单甲醚对大鼠不同器官细胞DNA损伤的器官亲和性研究

用污染食管癌高发现场粮食的优势菌互隔交链孢霉(Alternaria alternata)的主要毒素交链孢酚(AOH)和交链孢酚单甲醚(AME),诱发大鼠不同器官细胞的程序外DNA合成(UDS)。结果表明,AOH及AME在最高有效浓度时,诱发肝细胞掺入指数分别为0.45及0.55;诱发食管上皮细胞掺入指数分别为2.32和1.75;诱发肺细胞掺入指数分别为1.7和1.05;该结果提示,AOH及AME对食管上皮细胞具有显著的器官亲和性,大鼠食管可能为AOH及AME的重要靶器官之一。     

简讯

最近,我们和中国医学科学院肿瘤研究所陆士新教授协作,用林县分离的优势污染霉菌互隔交链孢霉代谢物交链孢酚单甲醚(AME)和交链孢酚(AOH)和人胎儿食管上皮作短期培养后,观察了二者对人食管上皮癌基因的作用。两轮转染NIH/3T 3细胞已获成功,     

[~3H]交链孢酚单甲醚口服后在大小鼠体内吸收、分布和排泄的研究

小鼠口服83μg/kg[~3H]交链孢酚单甲醚(AME)后,可经胃肠道吸收入血,血中放射性在30min即达高峰。组织中2h出现放射性,4h-8h达高峰。放射性在各个组织中均有分布,尤以心脏、皮肤、肝脏、睾     

交链孢酚单甲醚诱导大鼠骨髓嗜多染红细胞微核形成的研究

对交链孢酚单甲醚(alternariol monamethyl ether,AME)诱导大鼠骨髓嗜多染红细胞微核形成进行了实验研究。结果表明,AME在体内作用48h仍可以诱发大鼠骨髓嗜多染红细胞微核形成率增高。     

交链孢酚和交链孢酚单甲醚诱发人淋巴细胞DNA损伤的研究

用从食管癌高发区林县严重污染粮食的链格孢(Alternaria alternata)培养物中分离纯化的交链孢酚(AOH)和交链孢酚单甲醚(AME)诱发正常人外周血淋巴细胞程序外DNA合成(UDS)。结果表明:AOH及AME均可不同程度地诱发UDS,并发现AOH比AME作用更强。结果提示,AOH及AME可引起人外周血淋巴细胞DNA损伤,其提示与食管癌发生可能有关。     

交链孢酚单甲醚对细胞免疫的影响

交链孢酚单甲醚(Alternariol monomethylether,AME)是食管癌高发区林县粮食中分离的优势污染菌互隔交链孢霉(亦称链格孢菌)的毒素之一。多年的研究证实,该毒素具有致突变性和致癌性。为了进一步探讨其对免疫     

互隔交链孢霉毒素AME和AOH合成物的诱变性

对互隔交链孢霉毒素——交链孢酚单甲醚(Alternariol monomethyl ether,AME)和交链孢酚(Alternariol.AOH)的合成物进行了细菌回复突变试验.检测其诱变性。结果表明:AME和AOH提取物和合成物(不加S_9)对鼠伤寒沙门氏菌TA102菌株和大肠菌ND-160菌株.均显示致突变效应.而后者对AME和AOH更为敏感。用相同剂量.AOH对大肠杆菌ND—160菌株诱变比值(MR)比AME高2～7倍,表明AOH的诱变性更强。合成物与提取物相比,合成物的诱变作用较强。     

互隔交链孢霉毒素引起大鼠肝细胞DNA单链断裂的作用

应用碱性洗脱荧光分析法对互隔交链孢霉产生的两种主要毒素——交链孢酚单甲醚(Alternariol Monomethyl Ether.AME)和交链孢酚(Alternariol.AOH)引起大鼠肝细胞DNA单链断裂效应进行了研究。实验结果表明:二者都能引起大鼠肝细胞DNA单链断裂,并有明显的剂量效应关系.DNA在滤膜上的存留分数明显低于溶剂对照组.具有统计学意义(P<0.01)。结果提示AME和AOH有致突变作用,二者可能是林县食管癌的病因之一。     

交链孢酚单甲醚对鼠肝脂质过氧化及谷胱甘肽过氧化物酶的影响

用食管癌高发区林县的粮食中分离出的互隔交链孢霉的代谢物之一——交链孢酚单甲醚(AME)注入小鼠体内,观察对鼠肝中脂质过氧化及谷胱甘肽过氧化物酶活性的影响。试验结果显示:AME可以导致丙二醇含量增加(P<0.01),谷胱甘肽过氧化物酶活性降低(P<0.01)。丙二醛含量的增高与AME剂量呈显著正相关(r=0.957,P<0.05),酶活性与丙二醛水平呈明显负相关(r=-0.973,P<0.05)。结果表明:AME可以引发脂质过氧化反应,谷胱甘肽过氧化物酶活性下降,本实验结果为该霉菌极可能是引起食管癌病因之一学说提供的积极佐证。     

交链孢酚单甲醚对人胚食管DNA结合作用的研究及其结合键型的鉴别

应用吸收光谱分析法研究了交链孢酚单甲醚(Alterariol Monomethyl Ether,AME)对人胚食管DNA之间的结合作用并对结合的键型作了鉴别。研究表明,AME和DNA在37℃条件下,二者的最大吸收峰向长波方向明显位移。而且在AME和DNA结合之间存在剂量效应关系。AME和人胚食管DNA结合的最大分子比例(以AME:脱氧—磷酸核苷计)为5:1000,结合反应的平衡常数K=2.8×10~6,结合作用发生迅速而稳定。结合部位可能在碱基,无明显的碱基特异性。热变性DNA能结合更多的AME分子,说明二者的结合不需要DNA具有完整的二级结构。盐离子可严重干扰二者的结合,而脲对此则不产生明显影响,提示AME与DNA结合的主要键型为离子键而不是氢键型。AME与人胚食管DNA这种以离子键结合的方式可能在AME的诱变性/致癌性中起重要作用。     

小鼠灌服~3H交链孢酚单甲醚的体内蓄积作用

与单次灌胃相比,小鼠连续三次灌服~3H-AME后24 h,其血、胃肠道及内容物中有明显的放射性升高,各组织则未见升高;灌服后第4d测定,在胸腺、直肠、脑和皮肤等组织有明显的放射性升高,而食管、前胃、睾丸、小肠等组织则无明显升高。说明多次摄入AME后,先在血中累积,而组织中累积较晚,在所有组织中食管累积最不明显,可能与AME和食管上皮细胞的结合具有特异性强、亲和力高有关。     

^3H—镰刀菌素C在大鼠体内的分布及与DNA的结合

镰刀菌素C(Fusarin C,FC)是Wiebe和Bjeldanes(1971)首先从玉米中分离得到的一种霉菌毒素,本实验室于1984年也从串珠镰刀菌的玉米培养基中分离出该毒素,FC对细菌和哺乳类动物细胞均有明显的致突变作用.为探讨FC的致癌作用及其与林县食管癌高发的关系,本实验初步研究~3H-镰刀菌素C(~3H-FC)在大鼠体内的分布、代谢及在体外与大鼠食管的DNA结合.     

^3H—米托蒽醌在动物体内药代动力学研究

Mitoxantrone (DHAQ) we studied is a new semisynthetic antitumor drug prepared in China. This paper reports the pharmacokinetic studies of 3H-mitoxantrone in mice by liquid scintillation. The results showed that the decline of radioactivity in the plasma was a biphasic curve after intramuscular and intravenous injection in rats. The adsorption of 3H-DHAQ was ready and complete after intramuscular injection, it was widely distributed in body tissues. The concentration order of various organs was liver greater than intestine greater than kidney greater than lung greater than heart greater than muscles greater than brain. The elimination of the drug was slow, T1/2 was 42.56 h. In 72 h after administration the cumulative excretion of radioactivity in urine was 7% of the total dose, while that in feces was 43%. The main forms of the drug in urine were its metabolites.     

抗RSV脱氧核酶经鼻内给药后在小鼠体内脏器生物分布研究

目的探讨抗RSV脱氧核酶(DZ)经鼻内给药后在小鼠体内脏器的生物学分布。方法合成互补于RSV N基因的基因组转录起始序列的DZ1133:5’TGG GGC AAA GGC TAG CTA CAA CGA ACA AAG ATG 3,’5’端和3’端的2-3个碱基进行硫代修饰,3’端连接一个胆固醇,再进行125I标记。小鼠麻醉后鼻内给药,分别于不同时间点处死小鼠并取各脏器及血液,γ计数仪测放射性计数。结果滴鼻给药后,DZ很快进入肺部和胃肠道并有少量药物吸收入血并进入其他脏器,肺部放射性浓度仅次于胃肠道,于6小时达最高峰,为总药物放射量的15.59%,24小时仍有4.9%的药物存留肺部,其浓度远远高于其他脏器。在其他脏器中,6小时脏器放射性大小依次为肝脏〉肾脏〉心脏〉脾脏〉脑部。结论肺作为DZ治疗RSV感染的靶器官,经麻醉后鼻内给药后能够达到有效浓度,且持续较长时间,建议用药间隔为24小时。     

五加皮Age蛋白在正常小鼠与荷瘤小鼠体内的组织分布

目的探讨五加皮抗肿瘤成分A ge蛋白在正常小鼠与荷瘤小鼠体内的组织分布。方法用氯胺T法对A ge蛋白进行125I标记(形成125I-A ge),由尾iv小鼠后,于不同时间取组织和血液标本,测定放射cpm比值。以放射参与量(即脏器与血液中cpm比值)作为125I-A ge在组织中分布的依据。结果在一次性快速iv125I-A ge 2 h后,正常小鼠和荷瘤小鼠体内均以肾脏中125I-A ge的分布量最高,肝脏和肺部放射参与量也较高,与心脏、脾脏等其他脏器相比差异有显著性(P<0.01);尿中125I-A ge的量很高。iv同等剂量125I-A ge后,荷瘤小鼠的肾脏、肝脏和肺部组织的放射参与量比正常小鼠偏高(P<0.05)。结论五加皮A ge蛋白在小鼠体内主要分布于血流丰富的组织,主要通过泌尿系统排泄,不易透过血脑屏障。     

婴儿双歧杆菌对小鼠黑色素瘤模型肿瘤组织的靶向性

目的：探讨婴儿双歧杆菌对黑色素瘤组织是否具有靶向特性。方法：采用荷瘤鼠尾静脉推注。H-TdR标记婴儿双歧杆菌示踪分析、组织培养和组织切片革兰氏染色观察婴儿双歧杆菌的瘤组织靶向性。结果：瘤组织内放射性强度持续增强，正常组织放射性强度则持续减弱。组织培养显示婴儿双歧杆菌在瘤组织内富集增殖。组织切片显示瘤组织内大量革兰氏染色阳性条杆状紫蓝色深染区，而正常组织中却无。结论：婴儿双歧杆菌对黑色素瘤具有较好的靶向性。     

99m Tc-HL91 "hot spot" imaging of mice bearing human carcinoma by gamma camera and the effects of tumor necrosis on imaging

Objective To evaluate the hypoxia-avid agent ^99m Tc-HL91 (^99m Tc labeled 4, 9-diaza-3, 3, 10, 10-tetramethyldodecan-2, 11-dione dioxime) as the tracer of tumor "hot spot" imaging and the influence of tumor necrosis on the image.
Methods After injection of ^99m Tc-HL91, 6 nude mice bearing human breast cancer MCF-7 and 18 nude mice bearing human pancreatic adenocarcinoma were subjected to gamma camera imaging, postmortem analysis, and autoradiography and imaging of tumor sections.
Results The image of tumor was identified 1 hour after injection of ^99m Tc-HL91.Images demonstrated gradually increased ^99m Tc-HL91 uptake in the tumor 1-12 hours after injection (P<0.05-0.001).Six hours after injection, the radioactivity ratios of tumor to thorax and tumor to head were higher than 2.1.Six hours after injection, the radioactivity ratios of tumor to brain, muscle, blood, heart, lung and kidney in pancreatic adenocarcinoma bearing nude mice were 101.0±114.7, 30.0±30.3, 19.9±21.9, 14.4±15.1, 3.71±2.41 and 0.46±0.26, respectively, and the radioactivity ratios in breast cancer MCF-7 bearing nude mice were close to these figures.The radioactivity of non-necrotic tumor was 3.77 times that of necrotic tumor.However, the radioactivity ratios of tumor to liver, intestine and stomach were lower than 1.3. Autoradiographs and images of tumor sections showed that the radioactivity was higher in the region of solid tumor than in the necrotic region.
Conclusion ^99m Tc-HL91 via gamma camera positively identifies regional tumor in nude mice bearing human cancer.^99m Tc-HL91 retention is lower in necrotic tumor than in non-necrotic tumor.The low radioactivity ratio of tumor to abdominal organs limits the application of ^99m Tc-HL 91 in detecting abdominal tumors.      

3H-TdR标记人骨髓间充质干细胞移植治疗mdx鼠的实验研究

目的 探讨人骨髓间充质干细胞移植mdx鼠能否修复骨骼肌肌膜病变及干细胞在其体内的分布特点.方法 用氚-脱氧胸腺嘧啶(3H-TdR)标记人骨髓间充质干细胞(hBM-MSCs),以每只鼠干细胞1×10⁷/0.3 ml经尾静脉注入18只免疫抑制的mdx鼠(8～10周龄).于移植后24 h、48 h、2周、1月、2月、4月处死鼠,分别测定各组织器官的放射活性;用免疫荧光法检测骨骼肌肌膜营养障碍基因(dystrophin,Dys)表达情况.结果 移植后1月,多数组织、器官放射活性显著高于对照组,其中以骨髓、肝、脾放射活性增高更为明显.大多数组织器官放射活性随时间推移逐渐下降,而骨骼肌放射活性的从2周时开始逐渐升高,于1月时达到高峰(27.6±3.3 Bq/mg湿重).1月之后,骨髓、骨骼肌放射活性仍保持较高水平.免疫荧光显示移植后24 h、48 h、2周骨骼肌Dys免疫荧光呈阴性,1月后呈阳性,1月、2月、4月阳性率分别为:6.6%、8.4%、8.9%.结论 hBM-MSCs能植入mdx鼠体内,并融合、分化为骨骼肌,部分修复骨骼肌肌膜病变;hBM-MSCs移植入mdx鼠后早期主要分布在骨髓、肝、脾,后期主要分布在骨髓、骨骼肌.     

^3H-TdR标记人骨髓间充质干细胞移植治疗mdx鼠的实验研究

OBJECTIVE: To investigate the feasibility of using human bone marrow-derived mesenchymal stem cells (hBM- MSCs) for repairing the skeletal muscle sarcolemma lesions in mdx mice and characterize the distribution of the transplanted hBM-MSCs. METHODS: Eighteen 8- to 10-week-old immunosuppressed mdx mice received transplantation with 1x10(7) of hBM-MSCs (the fifth passage) with 3H-thymidine (3H-TdR) labeling by injection of the cells into the tail vein. The mice were killed at 24 h, 48 h, 2 weeks, and 1, 2 and 4 months after the transplantation, respectively, to measure the radioactivity in the tissues and organs. Dystrophin expression on the sarcolemma was detected by immunofluorescence analysis. RESULTS: One month after transplantation, the mice with cell transplantation showed greater radioactivity in most of the tissues and organs than the control mice, especially in the bone marrow, liver and spleen. The radioactivity was then gradually lowered but in the skeletal muscle, the radioactivity increased progressively since 2 weeks after transplantation, reaching the peak of 27.65+/-3.53 Bq/mg at 1 month. Compared with that in the control mice, the radioactivity in the bone marrow and skeletal muscle was persistently higher in mice with cell transplantation 1 month after transplantation. No dystrophin-positive cells were found in the mdx mice at 2 weeks but detected at 1 month. The percentage of dystrophin-positive fibers in each section ranged from a 6.6% (1 month) to 8.9% (4 months). CONCLUSIONS: hBM-MSCs engrafted in immunosuppressed mdx mice may differentiate into skeletal muscle cells to repair the pathological lesion of the skeletal muscle sarcolemma. The hBM-MSCs reside mainly in the bone marrow, liver and spleen in the early stage following transplantation, homing into the bone marrow and skeletal muscle later.