刺五加抗癌作用的实验研究

目的：为进一步探讨刺五加对实验性肝癌发的干预作用及可能机理。方法：４３只雄性大鼠被随机分成３组（１）正常对照组：喂普通饲料（２）３－ＭｅＤＡＢ组：喂含０．０６％３－ＭｅＤＡＢ饲料１０周（３）刺五加组,除致癌剂外另加入刺五加,历时２０周。实验过程中所有动物均自由进食及饮水。结果：刺五加组较３－ＭｅＤＡＢ组：Ｆ（１）外周血液及肝组织中ＰＡＩ－１含量明显减少。（２）肝细胞周期时相Ｇ０／Ｇ１比率增加,Ｓ期     

EGFR与C－erbB－2癌基因蛋白在甲状腺乳头状腺癌中的表达

本文作者研究了上皮生长因子受体（ＥＧＦＲ）和Ｃ－ｅｒｂＢ－２癌基因蛋白在５０例甲状腺癌和６６例甲状腺良性疾患中的表达。５０例甲状腺癌中，ＥＧＦＲ阳性者２６例（５２％），Ｃ－ｅｒｂＢ－２阳性者２５例（５０％）。ＥＧＦＲ和ｃ－ｅｒｂＢ－２共同表达阳性者的淋巴结转移率（９２．８５％）明显高于两者共同表达阴性者（６１．５３％）（Ｐ＜０．０５）。ＥＧＦＲ阳性者ＡｇＮＯＲ数（２．５９±０．６４／核）也明显高于ＥＧＦＲ阴性者（１．３９±０．１８／核）（Ｐ＜０．００１）。ＥＧＦＲ与Ｃ－ｅｒｂＢ－２共同表达阳性，同时ＡｇＮＯＲ计数高的甲状腺癌具有较高的恶性度。因此，对这种病人要予以特别的治疗措施并抓紧随访工作。     

LIVER TUMOUR PORMOTION BY MICROCYSTIN LR ANDAFLATOXIN B1 IN TWO-STAGE MEDIUM-TERM ANIMALTEST

为评价微囊藻毒素ＬＲ（ＭＣＬＲ）和黄曲霉毒素Ｂ＿１（ＡＦＢ＿１）对大鼠肝脏的促癌作用,采用二阶段中期动物试验模型进行了研究。６周龄雄性Ｆｉｓｈｅｒ３４４大鼠腹腔注射二乙基亚硝胺（ＤＥＮ,２０Ｏｍｇ／ｋｇ）作为起始剂,在第２周未腹腔注射ＡＦＢ＿１（０.５ｍｇ／ｋｇ）,第３周至第８周每周２次腹腔注射ＭＣＬＲ（ｌ或１０μｇ／ｋｇ）。所有大鼠在第３周末进行２／３部分肝切除,第８周末全部处死,通过在肝切片上测量单位面积肝组织中胚胎型谷胱甘肽８转移酶（ＧＳＴ－Ｐ）阳性灶的数量和面积作为肝脏癌前病变的指标。结果表明ＭＣＬＲ和ＡＦＢ＿１在ＤＥＮ起始下能显著增加ＧＳＴ－Ｐ阳性灶的数量和面积,ＭＣＬＲ单独作用也能显著增加ＧＳＴ－Ｐ阳性灶的面积,提示ＭＣＬＲ为大鼠肝脏的促癌剂,并且ＭＣＬＲ与ＡＦＢ＿１具有协同促癌作用。这对肝癌高发区动员居民改饮沟塘水为深井水有现实意义。     

超大剂量化疗合并APBSCT治疗恶性肿瘤四例报告

目的为了探讨超大剂量化疗（ＨＤＣＴ）合并自体外周血造血干细胞移植（ＡＰＢＳＣＴ）治疗恶性肿瘤的临床意义。方法经病理证实的４例晚期恶性肿瘤接受了该治疗，采用小剂量Ｇ－ＣＳＦ加或不加化疗动员外周血造血干细胞（ＰＢＳＣ），均莸得足够的干细胞数量。３例患者采用ＣＴＸ５．６ｇ／ｍ２＋ＶＰ－１６１４００ｍｇ／ｍ２＋ＣＢＰ１０００ｍｇ／ｍ２，１例患者采用ＣＴＸ４．０ｇ／ｍ２＋ＥＰＩ１３０ｍｇ／ｍ２超大剂量化疗方案。结果化疗后完全缓解１例，部分缓解３例。ＡＰＢＳＣＴ后造血功能恢复非常迅速。结论采用化疗和／或小剂量Ｇ－ＣＳＦ动员ＰＢＳＣ是安全的和可行的，在ＡＰＢＳＣＴ支持下应用超大剂量化疗治疗对化疗敏感的恶性实体瘤是值得探索的方法。     

胃癌多基因表达的同步检测

应用ＬＳＡＢ和ＡＢＣ法对７５例胃癌及癌旁组织进行了ｐ５３、ｃ－ｅｒｂＢ－２、ＥＧＦＲ和ｒａｓ表达的研究。结果显示：（１）７５例胃癌ｐ５３、ｃ－ｅｒｂＢ－２、ＥＧＦＲ和ｒａｓ表达阳性率分别为４１．３％、１８．７％、６１．３％和４６．７％。ｐ５３在肠型胃癌中阳性率为５２．６％，高于弥漫型胃癌的２９．７％（Ｐ＜０．０５）；在早期胃癌中阳性率较高（６０．０％），癌旁重度异型增生亦有阳性表达（２／４）。ｃ－ｅｒｂＢ－２阳性表达只限于癌灶，而癌旁组织均为阴性。ｃ－ｅｒｂＢ－２在高分化胃癌中阳性率较高（Ｐ＜０．０５）。ＥＧＦＲ表达与胃癌的大体类型、生长方式、分化程度、淋巴结受累和远处转移呈正相关（Ｐ＜０．０５）。（２）ｃ－ｅｒｂＢ－２和ＥＧＦＲ在胃癌中的表达互相独立。（３）ｒａｓ表达与ＥＧＦＲ表达呈正相关，而与ｃ－ｅｒｂＢ－２呈负相关。（４）ｐ５３表达与其它基因表达无明显关系。上述结果表明，胃癌发生发展过程中伴有多种癌基因的变化，其出现时间不同，意义也不一样。     

C－erbB－2，人表皮生长因子及其受体在大肠癌中表达的意义

用ＡＢＣ免疫组化法测定２００例大肠癌组织中Ｃ－ｅｒｂＢ－２，人表皮生长因子（ｈＥＧＦ）及其受体（ＥＧＦＲ）。结果发现：１）Ｃ－ｅｒｂＢ－２，ｈＥＧＦ，ＥＧＦＲ在２００例大肠癌中阳性表达分别为３６％、４４％、４７％，三者共同阳性为１６．５％。２）ｈＥＧＦ，ＥＧＦＲ在大肠癌ＤｕｋｅｓＣ、Ｄ期，肿瘤＞２ｃｍ、低分化腺癌，有深度浸润和淋巴结转移者阳性率显著高于其它各型（Ｐ＜０．０１）。３）Ｃ－ｅｒｂＢ－２，ｈＥＧＦ和ＥＧＦＲ阳性病例存活率明显低于这些阴性病例（Ｐ＜０．０１）。结果表明，Ｃ－ｅｒｂＢ－２，ｈＥＧＦ和ＥＧＦＲ在大肠癌的侵袭性生长中起重要作用，ｈＥＧＦ和ＥＧＦＲ可作为大肠癌患者高度恶性的生物学指标。     

OLT对AFB1致树Qu肝癌前病变的化学预防作用

目的：应用树Ｑｕ进行Ｏｌｔｉｐｒａｚ（ＯＬＴ）对黄曲霉毒素Ｂ１（ＡＦＢ１）的化学预防研究。方法：实验树Ｑｕ按不同处理方法分为４组：Ａ组：正常对照;Ｂ组：ＡＦＢ１;Ｃ组：ＡＦＢ１＋药１（ＯＬＴ７次／周,共５周）;Ｄ组：ＡＦＢ１＋药２（ＯＬＦ１次／周,共５周）。动物处死后肝细胞作低温石蜡连续切片,分别染γ－ＧＴ、ＧＳＴ－Ｐ及ＨＥ。结果：Ｃ组与Ａ组树Ｑｕ肝内均有较多沿汇管区分布的γ－ＧＴ阳性肝细胞群;而     

大白菜抑制大鼠体内致癌物PhIP-DNA加合物形成及其可能的作用机理

目的研究大白菜（ｂｒａｓｓｉｃａｃｈｉｎｅｎｓｉｓ）对结肠致癌物２－氨基－１－甲基－６－苯基咪唑［４,５－ｂ］吡啶（ＰｈＩＰ）致癌的预防作用及机理。方法雄性ＳＤ大鼠喂饲基础饲料或掺有大白菜粉（２０％）混合饲料１０天后,经口摄入ＰｈＩＰ（１０ｍｇ／ｋｇ）。以３２Ｐ－后标记方法分析动物结肠粘膜、心、肺和肝中ＰｈＩＰ－ＤＮＡ加合物含量,并测定参与ＰｈＩＰ代谢的细胞色素Ｐ４５０（ＣＹＰ）１Ａ１和１Ａ２以及谷胱甘肽转硫酶（ＧＳＴ）活性。结果经喂饲含大白菜饲料的大鼠,其结肠、心、肺、肝等器官中,ＰｈＩＰ－ＤＮＡ加合物含量显著低于喂饲基础饲料的动物（Ｐ＜０．０１）,抑制率结肠为８２．３％、心脏为６０．６％、肺为４８．４％、肝脏为４８．９％。大白菜对参与ＰｈＩＰ解毒的ＣＹＰ１Ａ１和ＧＳＴ有显著的诱导作用。与对照组比较,喂饲大白菜大鼠的肝ＣＹＰ１Ａ１活性增加８０．６％（Ｐ＜０．０１）,肝和肺细胞浆ＧＳＴ活性分别增加１８．２％和３５．６％（Ｐ＜０．０５）。结论食用大白菜可有效抑制ＰｈＩＰ－ＤＮＡ加合物形成,其作用机理可能是诱导解毒酶     

细胞色素P4501A1,2D6和谷胱甘肽硫转移酶基因多态性与肺癌易感性的研究

目的探讨细胞色素Ｐ４５０１Ａ１（ＣＹＰ１Ａ１），２Ｄ６（ＣＹＰ２Ｄ６）和谷胱甘肽硫转移酶（ＧＳＴＭ１）基因多态性与肺癌易感性的关系。方法用病例对照研究方法及ＰＣＲ┐ＲＦＬＰ等技术检测原发性肺癌和住院对照各５９例，分析ＣＹＰ１Ａ１基因ＭｓｐＩＣ型、ＣＹＰ２Ｄ６Ｃｈ型（Ｔ／Ｔ型）和ＧＳＴＭ１缺陷型〔ＧＳＴＭ１（－）〕三种纯合突变型频率分布及其交互作用。结果突变型在病例和对照组的频率分别为（ＣＹＰ１Ａ１ＭｓｐＩＣ型２５．４％、１５．３％（Ｐ＝０．１７），ＣＹＰ２Ｄ６ＣｈＴ／Ｔ型３５．６％，４７．５％（Ｐ＝０．２６），ＧＳＴＭ１（－）型５７．６％、４９．２％（Ｐ＝０．４６），无显著性差异。协同分析发现在男性中，１１．６％（５／４３）肺癌兼有ＭｓｐＩＣ型和ＧＳＴＭ１（－）型，对照组无１例（０／４３），Ｐ＝０．０３。结论结果提示在男性中ＣＹＰ１Ａ１ＭｓｐＩＣ型和ＧＳＴＭ１（－）型可能协同增加患肺癌的危险性。     

rhG-CSF预防恶性肿瘤化疗后粒细胞减少的Ⅱ期临床研究

目的：评价ｒｈＧ－ＣＳＦ（粒生素）对预防恶性肿瘤化疗后粒细胞减少的作用及不良反应。方法：人组总数６３例,均为病理或细胞学证实的恶性肿瘤。采用自身交叉方法将患者随机分入ＡＢ和ＢＡ两组。Ａ为治疗周期,即化疗用药结束４８ｈ开始,每日１次皮下注射ｒｈＧ－ＣＳＦ ５μｇ／ｋｇ,连续用药７～１４ｄ。Ｂ为空白对照周期。自化疗开始隔日查血常规１次,观察中性粒细胞（ＡＮＣ）及白细胞（ＷＢＣ）的变化。结果：治疗组于ｒｈＧ－ＣＳＦ注射２４ｈ后,ＷＢＣ及ＡＮＣ迅速上升,４８ｈ出现第１个高峰,第１０天出现第２个高峰,而对照组化疗后,ＷＢＣ和ＡＮＣ逐渐下降,始终低于治疗组。ＷＢＣ,ＡＮＣ的最低值、ＷＢＣ＜４．０×１０９／Ｌ、ＡＮＣ＜２．０×１０９／Ｌ的持续时间,以及化疗后第２１天ＷＢＣ＜４．０×１０９／Ｌ的病例数在治疗组和对照组间差异有显著性（Ｐ＜０．０５）。结论：ｒｈＧ－ＣＳＦ可以促进化疗患者ＷＢＣ和ＡＮＣ的恢复,耐受性良好,可以作为肿瘤化疗中提高剂量强度的有效辅助药。     

Relative contribution of dietary protein level and aflatoxin B1 dose in generation of presumptive preneoplastic foci in rat liver

Male weanling F344 rats were orally gavaged with aflatoxin B1 (AFB1) in daily doses of 200, 235, 270, 300, and 350 micrograms/kg/day for a total of 10 doses over a 12-day period, and then 1 week after the last dose they were fed diets of varying protein (casein) content to compare the contribution of AFB1 dose and dietary protein level on the development of presumptive preneoplastic gamma-glutamyltransferase-positive (GGT+) foci in rat liver. All animals were fed the same 20% dietary casein level during the dosing period. One week after the end of the dosing period, one-half of the animals in each dose group were then continued on the 20% casein diet for the entire 12-week foci-development period; the remaining half in each dose group were fed lower levels of dietary casein during the foci-development period for the increasing AFB1 dose groups (20, 16, 12, 8, and 4% casein for the 235-, 250-, 270-, 300-, and 350-micrograms/kg/day groups, respectively). The AFB1 dose groups used were determined in a preliminary experiment. In this previous experiment, a clearly discernible threshold dose at about 100-150 micrograms AFB1/kg/day (below which no GGT+ foci were observed) and a steep slope between 150 and 400 micrograms/kg/day were produced. In the second experiment, while the expected positive slope of (AFB1) dose versus (GGT+ foci) response relationship was found for animals fed the 20% casein diet, the dose response for the animals fed the lower levels of casein was eliminated, providing evidence that nutrient intake during the postdosing foci development is more rate limiting toward the development of these preneoplastic lesions than is the carcinogen dose.     

The influence of partial hepatectomy on the biphasic response of gamma glutamyl transpeptidase to aflatoxin B1

We previously observed a biphasic response in rat hepatic gamma glutamyl transpeptidase (GGT) activity to aflatoxin B1 (AFB1) feeding [9]. We have extended this observation to examine the effect of partial hepatectomy (PH) on the activity and distribution of GGT at different stages of the feeding regime. In control-fed animals GGT levels were elevated 3-7 days after PH with increased activity in periportal hepatocytes. In animals fed a sub-carcinogenic dose of AFB1 (up to 4 weeks) the effect of PH on GGT activity was similar to that in control animals, but increased activity was mainly due to biliary hyperplasia. There was no obvious difference between animals returned to control diet after PH and those returned to toxic diet. In animals fed 4-15 weeks the percentage increase in GGT activity 1 week after PH correlated with length of time on AFB1 diet before operation, with an increase in number and size of altered foci. These results further support the idea that there is a preliminary toxic response in GGT activity followed by a secondary response more closely related to the carcinogenic process.     

Suppression of aflatoxin B1-induced hepatotoxic lesions by crocetin (a natural carotenoid)

The suppressive effects of crocetin (a natural carotenoid) on the hepatotoxic lesions induced by aflatoxin B1 (AFB1) were investigated in male Wistar rats. Rats were divided into five groups: groups I and II served as normal and solvent control respectively. Group III was given AFB1 (25 micrograms/day/rat) alone; group IV was given crocetin (0.1 mg/day/rat) alone; and group V received both AFB1 and crocetin. Rats received AFB1 and crocetin for 9 and 10 weeks respectively, and were maintained on basal diet for 35 weeks. At the end of the experiment (week 45), the incidence of liver lesions in rats of group V was significantly reduced by approximately 40% compared with group III. There were no liver lesions in rats of groups I, II and IV. A significant protective effect of crocetin on AFB1 hepatotoxicity was shown, as manifested by reduced effects on the activities of serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and gamma-glutamyl transpeptidase (P less than 0.01-0.001). From our previous results and present data, we suggest that the suppression of crocetin on AFB1 hepatotoxicity in the rats might be due to the defense mechanisms of hepatic tissues that elevated the GSH S-transferase activity and decreased the formation of hepatic AFB1-DNA adducts.     

Enhancing effect of ethanol on aflatoxin B1-induced hepatocarcinogenesis in male ACI/N rats

The modifying effect of ethanol (EtOH) on aflatoxin B1 (AFB1)-induced hepatocarcinogenesis was examined in male ACI/N rats by chronic treatment at the post-initiation phase. Rats received an ip injection of AFB1 (1.5 mg/kg) twice a week for 10 weeks (a total of 20 doses). Following a week of acclimation, they were given 10% EtOH as drinking water for 56 weeks. The effect of EtOH on the hepatocarcinogenesis was evaluated in terms of the incidence of altered hepatocellular foci and neoplasms at the end of the experiment. Exposure to AFB1 alone induced a substantial number of altered foci (6.98 iron-excluding foci/cm2) in rats. The number of altered liver cell foci in rats receiving AFB1 followed by EtOH was significantly increased (26.39 iron-excluding foci/cm2). In the rats given EtOH after AFB1, the total area and mean diameter of both iron-excluding foci and altered foci identified in hematoxylin and eosin-stained sections were significantly higher than in the rats exposed to AFB1 alone. The incidence of liver cell tumors of the group given AFB1 and EtOH (3/15, 20%) was higher than that of the group treated with AFB1 alone (0/14, 0%). Treatment with EtOH alone for 56 weeks did not induce either. These results indicate an enhancing effect of EtOH on AFB1-induced hepatocarcinogenesis when it is given in the promotion phase.     

Minimal dose and time protection by lindane (gamma-isomer of 1,2,3,4,5,6 hexachlorocyclohexane) against liver tumors induced by aflatoxin B1

This study was carried out in order to investigate the minimal exposure to lindane (LD, 99.72% gamma isomer of 1,2,3,4,5,6 hexachlorocyclohexane), a chlorinated hydrocarbon insecticide, required to protect against liver tumor induced by aflatoxin B1 (AFB1). Materials fed to Buffalo strain rats were as follows: LD 100 ppm; AFB1 1 ppm, LD 100 ppm plus AFB1 1 ppm; and control basal diet. The experimental animals were clinically observed and then serially killed at 1, 3, 5, 10, 15 and 82 weeks. Concurrent administration of LD with AFB1 to rats for more than 3 weeks totally inhibited the incidence of AFB1-induced hepatocellular carcinomas by week 82. Only 1 of 20 rats (5%) fed the same regimen for 1 week developed liver tumors. Animals given 1 ppm AFB1 singly for 15 weeks had a high liver tumor incidence (31.5%). No animals developed liver tumors in LD-treated and control groups. LD may inhibit AFB1-induced liver tumors by stimulating hepatic metabolism and excretion of AFB1 so that less carcinogen is available to liver tissue.     

A single dose-response effect of aflatoxin B1 on rapid liver cancer induction in two strains of rats

To investigate rapid liver cancer induction in rats by aflatoxin B1 (AFB1), different single oral doses of AFB1 were given to 3 groups of 1-year-old Buffalo and Wistar rats. The animals were treated once and all survivors were killed 6 weeks later. Control animals received an equal volume of solvent (DMSO), and both groups of animals were maintained under identical conditions throughout the period of experiment. The survival rates were 40% with low and medium doses in AFB1-treated Buffalo and Wistar rats, and 0% in the high-dose Buffalo rats. Slight ante-mortem elevations in serum concentrations of glutamic pyruvic transaminase (SGOT) and glutamic oxaloacetic transaminase (SGPT) were indicative of the persistent damage effect of AFB1 at week 6. Total protein and albumin concentrations were not altered. The percent incidence of altered cell foci (areas) and neoplastic nodules was higher in Wistar than in Buffalo rats given a similar low dose. Various stages of well differentiated hepatocellular carcinomas (0.1-0.2 cm in diameter) developed in 3 of 8 Wistar rats. It thus appears that Wistar rats are more susceptible to hepatocarcinogenesis following a single oral dose of AFB1 than Buffalo rats.     

CYP3A4在黄曲霉毒素B1诱发大鼠肝癌过程中的表达及意义

探讨CYP3A4在黄曲霉毒素B1（AFB1）实验诱发大鼠肝癌过程中的活性变化及其在肝癌发生过程中的意义。方法:雄性、4周龄、Wistar大鼠随机分为AFB1组和对照组;AFB1组腹腔注射AFB1,对照组则给与溶媒二甲基亚砜。在诱发肝癌过程中,分别于第13、23、33、43、53、63周对大鼠进行肝活检;实验至第73周处死全部动物取肝组织;利用大鼠肝组织微粒体混合酶体外代谢体系,采用荧光分光光度定量法动态检测肝标本中CYP3A4酶活性。结果:AFB1组肝细胞癌发生率为58.8%（10/17）;对照组肝细胞癌发生率为0（0/16）,两组间肝癌发生率比较,AFB1组显著高于对照组（P=0.001）。两组大鼠肝组织代谢酶CYP3A4活性都有不同程度的变化。肝组织CYP3A4活性从13 w开始逐渐升高,至23 w达顶峰,然后逐渐降低,到43 w又升高,出现双波峰变化;从13 w至53 w不同时段AFB1组肝组织CYP3A4活性显著低于对照组（P<0.01）。但是至63 w时AFB1组肝组织CYP3A4活性基本接近对照组（P=0.5086）。结论:CYP3A4活性在AFB1诱癌过程中受到抑制,可能是由于癌变早期的细胞减少对致癌物质的活化有关;CYP3A4活性在AFB1诱癌过程中的表达起伏变化,是由于基因多态性较大程度上影响蛋白表达水平的结果。      

Enhancement of GST-P-positive liver cell foci development by nivalenol, a trichothecene mycotoxin.

In order to elucidate whether T-2 toxin (T-2) and nivalenol (NIV), the naturally occurring trichothecene mycotoxins in food and feed, are carcinogenic or possess an ability to modulate aflatoxin B1 (AFB1)-induced hepatocarcinogenicity, a medium-term liver bioassay was carried out. F344 male rats were given a single i.p. injection of diethylnitrosamine (DEN, 200 mg/kg), and then fed the test trichothecenes in diet (2 and 5 p.p.m. T-2 or 6 p.p.m. NIV) for 6 weeks beginning 2 weeks after the injection. Some control groups received DEN alone. For synergism between AFB1 and the trichothecenes, DEN-initiated rats as above were given a single i.p. injection of AFB1 (0.5 mg/kg) 2 weeks later and were fed a NIV-containing diet (6 p.p.m.) for 6 weeks. The other control group received the vehicle alone. Control rats not initiated with DEN were also treated with AFB1, NIV or T-2 alone as above. All rats were subjected to a two-thirds partial hepatectomy (PH) at week 3 and killed at week 8, and liver sections were analyzed by glutathione S-transferase placental form (GST-P) expression. In rats that did not receive DEN, AFB1 alone enhanced both the numbers and areas of GST-P-positive foci as reported earlier, while NIV or T-2 alone induced no marked changes. In rats initiated with DEN, AFB1 caused a marked expression of GST-P, and thus the hepatocarcinogenicity of AFB1 was reconfirmed. The expression of GST-P foci in rats fed T-2 or NIV was found to be at background level, indicating that the hepatocarcinogenicity was not predicted for the trichothecene mycotoxins such as T-2 and NIV by this medium-term bioassay system. In the group initiated by DEN followed by AFB1, on the other hand, an elevation of both the numbers and areas of GST-P-positive foci was observed by the subsequent feeding of rats with NIV, and this elevation was statistically significant from the sum totals of individual data of AFB1 or NIV alone. From this evidence, it is predicted that NIV causes an enhancing effect on AFB1-induced hepatocarcinogenesis.     

银杏叶提取物对AFB1所致大鼠肝癌基因P16Ink4a mRNA及蛋白表达的影响

  目的  动态观察银杏叶提取物(ginkgo biloba extract, EGb761)在抑制黄曲霉毒素B1(AFB1)诱发大鼠肝癌过程中对肝组织相关基因P161nk4a mRNA表达水平的影响, 进一步从分子生物学水平揭示银杏叶提取物抗癌的机制及其效果。  方法  将70只4周龄Wistar雄性大鼠随机分为3组: AFB1组(25只), AFB1+EGb761组(25只)及对照组(20只)。在诱发肝癌过程中, 分别于第13、33及53周对大鼠进行肝组织活检; 至第73周处死全部动物取肝组织。应用实时荧光定量PCR和Westernblot技术动态检测肝组织中P16Ink4a mRNA及相应蛋白的表达情况。  结果  AFB1组原发性肝癌发生率为58.8%(10/17);AFB1+EGb761组为29.4%(5/17);对照组为0(0/16) AFB1+EGb761组肝癌发生率显著低于AFB1组(P < 0.05)。AFB1+EGb761组的肝组织P16Ink4amRNA及相应蛋白表达水平在第53周及第73周时均明显高于AFB1组, 差异有统计学意义(P < 0.05)。  结论  银杏叶提取物(EGb761)具有抑制AFB1致大鼠肝癌的作用。其机制可能与调控肝细胞抑癌基因P16Ink4a mRNA表达水平有关。      

Reliability of a short-term test for hepatocarcinogenesis induced by aflatoxin B1.

The reliability of a short-term test for hepatocarcinogenesis induced by aflatoxin B1 (AFB1) was tested by comparing the early appearance of gamma-glutamyl transpeptidase (GGT)-positive foci with the occurrence of primary liver cancer at a later stage. All rats received a basic short-term treatment with AFB1 intraperitoneally, during which three experimental groups received Chinese green tea or 2000 or 5000 ppm butylated hydroxyanisole in the diet and a control group received basic diet. Some of the rats in each group were sacrificed at the end of the short-term procedure, and the remainder were observed up to 92 weeks. The livers of all animals were examined for GGT-positive foci or primary liver tumours. The GGT-positive foci were most numerous and largest and the incidence of liver tumours was highest in the control group. These findings suggest that GGT-positive foci are a valuable preneoplastic marker for AFB1-induced hepatocarcinogenesis, that the short-term model is fairly reliable, and that both Chinese green tea and butylated hydroxyanisole inhibit AFB1-induced hepatocarcinogenesis.