Comparative studies between humans and golden Syrian hamsters via thromboelastography

Background:Thromboelastography(TEG)is a widely utilized clinical testing method for real-time monitoring of platelet function and the thrombosis process.Lipid metab-olism disorders are crucial risk factors for thrombosis.The lipid metabolism charac-teristics of hamsters resemble those of humans more closely than mice and rats,and their relatively large blood volume makes them suitable for studying the mechanisms of thrombosis related to plasma lipid mechanisms.Whole blood samples from golden Syrian hamsters and healthy humans were obtained following standard clinical pro-cedures.TEG was employed to evaluate coagulation factor function,fibrinogen(Fib)function,platelet function,and the fibrinolytic system.Methods:The whole blood from hamster or healthy human was isolated following the clinical procedure,and TEG was employed to evaluate the coagulation factor func-tion,Fib function,platelet function,and fibrinolytic system.Coagulation analysis used ACLTOP750 automatic coagulation analysis pipeline.Blood routine testing used XN-2000 automatic blood analyzer.Results:TEG parameters revealed that hamsters exhibited stronger coagulation fac-tor function than humans(reaction time[R],p=0.0117),with stronger Fib function(alpha angle,p<0.0001;K-time[K],p<0.0001).Platelet function did not differ signifi-cantly(maximum amplitude[MA],p=0.077).Hamsters displayed higher coagulation status than humans(coagulation index[CI],p=0.0023),and the rate of blood clot dissolution in hamsters differed from that in humans(percentage lysis 30 min after MA,p=0.02).Coagulation analysis parameters indicated that prothrombin time(PT)and activated partial thromboplastin time(APTT)were faster in hamsters than in hu-mans(PT,p=0.0014;APTT,p=0.03),whereas the Fib content was significantly lower in hamsters than in humans(p<0.0001).No significant difference was observed in thrombin time(p=0.1949).Conclusions:In summary,TEG could be used to evaluate thrombosis and bleeding parameters in whole blood samples from hamsters.The platelet function of hamsters closely resembled that of humans,whereas their coagulation function was signifi-cantly stronger.

Identification of optimal reference genes in golden Syrian hamster with ethanol-and palmitoleic acid-induced acute pancreatitis using quantitative real-time polymerase chain reaction

Background:Acute pancreatitis(AP)is a severe disorder that leads to high morbidity and mortality.Appropriate reference genes are important for gene analysis in AP.This study sought to study the expression stability of several reference genes in the golden Syrian hamster,a model of AP.Methods:AP was induced in golden Syrian hamster by intraperitoneal injection of ethanol(1.35 g/kg)and palmitoleic acid(2 mg/kg).The expression of candidate genes,including Actb,Gapdh,Eef2,Ywhaz,Rps18,Hprt1,Tubb,Rpl13a,Nono,and B2m,in hamster pancreas at different time points(1,3,6,9,and 24 h)posttreatment was analyzed using quantitative polymerase chain reaction.The expression stability of these genes was calculated using Best Keeper,Comprehensive Delta CT,Norm Finder,and ge Norm algorithms and Ref Finder software.Results:Our results show that the expression of these reference genes fluctuated during AP,of which Ywhaz and Gapdh were the most stable genes,whereas Tubb,Eef2,and Actb were the least stable genes.Furthermore,these genes were used to normalize the expression of TNF-αmessenger ribonucleic acid in inflamed pancreas.Conclusions:In conclusion,Ywhaz and Gapdh were suitable reference genes for gene expression analysis in AP induced in Syrian hamster.

The Uniform Carcinogenic Action of Alkylnitrosoureas in Syrian Hamsters

The carcinogenic effects of a number of alkylnitrosoureas in Syrian golden hamsters have been compared by administering them by gavage as solutions in corn oil/ethyl acetate.The compounds were methyl-,ethyl-,2-hydroxyethyl-,2-oxopropyl-,and 2-phenylethylnitrosourea and the dialkylnitrosoureas dimethyl- and diethylnitrosourea,ethylnitrosohydroxyethylurea, ethylnitroso-2-oxopropylurea,2-oxopropylnitrosochloroethylurea,and hydroxyethylnitroso- ethylurea.All were given at approximately equimolar doses and,in most cases,to male and female hamsters.Most of the hamsters died with tumors associated with the treatments.Methyl- nitrosourea,ethylnitrosourea,and hydroxyethylnitrosourea,but not oxopropylnitrosourea, gave rise to a high incidence of tumors of the forestomach,while the dialkylnitrosoureas pro- duced smaller numbers of forestomach tumors.All of the alkylnitrosoureas induced hemangio- sarcomas of the spleen,which was the most common tumor produced by these carcinogens. Tumors of other types were uncommon,except that ethylnitrosourea and ethylnitrosohydroxy- ethylurea induced tumors of the cervix in about half of the animals and ethylnitrosooxopropyl- urea induced some nervous system tumors.The small number of common target organs of alkylnitrosoureas in hamsters contrasted sharply with the broad spectrum of tumors they in- duced in rats,depending on the nature of the alkyl groups,and with a quite different order of potency in the latter species,1989 Academic Press.Inc.

Coxsackievirus B3 HFMD animal models in Syrian hamster and rhesus monkey

Coxsackievirus B3(CVB3)is the pathogen causing hand,foot and mouth disease(HFMD),which manifests across a spectrum of clinical severity from mild to severe.However,CVB3-infected mouse models mainly demonstrate viral myocarditis and pancreatitis,failing to replicate human HFMD symptoms.Although several enteroviruses have been evaluated in Syrian hamsters and rhesus monkeys,there is no comprehensive data on CVB3.In this study,we have first tested the susceptibility of Syrian hamsters to CVB3 infection via different routes.The results showed that Syrian hamsters were successfully infected with CVB3 by intraperitoneal injection or nasal drip,leading to nasopharyngeal colonization,acute severe pathological injury,and typical HFMD symptoms.Notably,the nasal drip group exhibited a longer viral excretion cycle and more severe pathological damage.In the subsequent study,rhesus monkeys infected with CVB3 through nasal drips also presented signs of HFMD symptoms,viral excretion,serum antibody conversion,viral nucleic acids and antigens,and the specific organ damages,particularly in the heart.Surprisingly,there were no significant differences in myocardial enzyme levels,and the clinical symptoms resembled those often associated with common,mild infections.In summary,the study successfully developed severe Syrian hamsters and mild rhesus monkey models for CVB3-induced HFMD.These models could serve as a basis for understanding the disease pathogenesis,conducting pre-trial prevention and evaluation,and implementing post-exposure intervention.

ONCOGENIC TRANSFORMATION OF SYRIAN HAMSTER EMBRYO CELLS BY 5．3－MeV α PARTICLES AND A TUMOR PROMOTER PHORBOL ESTER

The primary Syrian hamster embryo(SHE) cells were used to study the oncogenic transformation by ￣(238)pu α particles or X-rays alone or in combination with a chemical promoter phorbol ester.Survival curves of SHE cells following exposure to α-particles or X-rays were fitted to single-or multi-target models,respectively. Model parameters were: Do = 0. 55 Gy. n = 1 for α particles 4 Do = 1.44 Gy. Dq = 3.0 Gy. n=7.7 for X-rays.Incidence of α particles or X-rays induced cell transformation was dose-dependant.α particles were more efficient in inducing cell transformation than that of X-rays. The enhancement of SHE cell transformation by phorbol 12-myristate 13-acetate(PMA) following exposure to α particles of 0. 25-1. 00 Gy was observed.

FURTHER STUDIES ON THE MALIGNANT TRANSFORMATION OF SYRIAN GOLDEN HAMSTER EMBRYO CELLS IN VITR0 BY THORIUM DIOXIDE AND RARE EARTH IRON MINERAL DUSTS

Malignant transformation of hamsterembryo cells was induced in vitro by rareearth iron mineral dusts(MP),naturalthorium(Th02) and MP plus Th02.Dusts of MP,MP plus Th02 or Th02 were added into themedium with the final concentration of 17.0,

无镁诱导仓鼠原代皮质神经元电生理学特性

目的无镁细胞外液建立癫痫放电模型,利用全细胞膜片钳技术,检测仓鼠原代皮质神经元的电生理学特性。方法采用生后1~2 d新生叙利亚仓鼠,分离大脑皮质培养原代神经元培养至第12天,分别予有镁细胞外液(有镁组)和无镁细胞外液(无镁组)孵育3 h,3 h后均更换为正常孵育液继续培养24 h。利用全细胞膜片钳技术,电压钳模式下记录神经元兴奋性突触后电流(excitatory postsynaptic currents,EPSC),电流钳模式下记录神经元兴奋性突触后电位(excitatory postsynaptic potentials,EPSP)。结果与有镁组相比,无镁组仓鼠原代皮质神经元EPSC[(124.38±75.15)Hz vs.(33.93±22.32)Hz,P<0.001]及EPSP[(37.05±38.37)Hz vs.(5.63±9.52)Hz,P<0.01]的频率升高,且差异有统计学意义;而两组之间EPSC及EPSP的振幅、曲线下面积和半宽度的差异无统计学意义(P>0.05)。结论无镁处理后仓鼠原代皮质神经元兴奋性升高,仓鼠原代皮质神经元可用于构建癫痫细胞模型。

氨基比林和亚硝酸钠诱发的肝内胆管癌动物模型

目的 用氨基比林和亚硝酸钠诱发叙利亚地鼠肝内胆管癌（ＩＣＣ）动物模型，观察胆管癌发生过程的病理变化。方法以 ８００ ｍｇ／Ｌ的氨基比林和亚硝酸钠溶液作为 ５０只 ６周龄叙利亚地鼠的饮用水，每周饮用 ６ ｄ，连续饮用 ２４周，定期分批处死动物，观察肝脏组织的病理学改变。结果 诱癌早期出现卵圆细胞增生、管状增生及小胆管的缀性增生，中期主要病变为肝内胆管上皮乳头状增生、化生、不典型增生和胆管纤维化，晚期可见肝内胆管腺瘤和腺癌。晚期肝内胆管癌的发生率达５０．０％（１０／２０）。结论该动物模型与人类肝内胆管癌发生发展的过程相似，方法简便、经济、可重复性好，具有良好的应用前景。肝内胆管的各种增生性病变与ＩＣＣ密切相关，尤其是不典型增生和胆管腺瘤，应视为ＩＣＣ的高危性癌前病变。

DIPN诱发金仓鼠肝内胆管癌动物模型

目的 建立肝内胆管癌 (ICC)动物模型 ,动态观察其发生发展的病理过程。方法 6周龄雄性金仓鼠 ,随机分为正常对照组、单纯结扎胆总管组和DIPN组 ,分别在实验的 5、1 0及 1 5周分批处死动物 ,观察其形态学变化。结果 诱癌早期出现卵圆细胞增生、管状增生及小胆管的囊性增生 ,中期主要病变为肝内胆管上皮乳头状增生、化生、不典型增生和胆管纤维化 ,晚期可见肝内胆管腺瘤和腺癌。其 1 0周和 1 5周肝内胆管癌的发生率分别是 2 0 % ( 1 /1 0 )和 6 7.0 % ( 1 0 /1 5)。结论 该动物模型能够模拟人类肝内胆管癌发生发展的过程 ,方法简便 ,可重复性好 ,具有良好的应用前景。肝内胆管的各种增生性病变与ICC密切相关 ,尤其是不典型增生和胆管腺瘤 ,应视为ICC的高危性癌前病变。

SPF级金黄地鼠的主要生物学特性

目的测定SPF级金黄地鼠的生物学特性数据,为生物制品的生产、检定及科学研究提供标准化的SPF级金黄地鼠。方法在5周龄、10周龄和30周龄群体中随机抽样20只地鼠,雌雄各半。测定生长发育、繁殖性能、淘汰种鼠干物质及粗脂肪含量、解剖学特性以及血液生理生化指标等生物学特性指标。结果从SPF级金黄地鼠的生长和繁殖特性来看,通过严格的选择和淘汰,SPF级金黄地鼠的生长、繁殖等特性已保留下来,同比原种群得到进一步提高。其体重和主要脏器重量、脏器系数的数据在5、10和30这三个日龄段基本稳定一致,呈现正常的生长规律;该鼠群的血常规、血液生化指标和免疫指标也比较稳定一致,个体间的差异很小。结论本实验测定的SPF级金黄地鼠的主要生物学特性,将为SPF级金黄地鼠进一步标准化提供极其重要的依据。

糖尿病金黄地鼠喂饲高脂食物诱发肾脏损伤

目的:利用对高脂食物敏感的金黄地鼠,在注射链脲佐菌素(STZ)诱发糖尿病后喂饲高脂食物,观察肾脏损伤变化。方法:30只90-100g雄性地鼠首先分成2组,1组注射STZ作为糖尿病组,另1组作为对照。9d后检测血糖,以空腹血糖大于200mg/dL作为糖尿病造模成功的标准,糖尿病动物随机分为2组,分别饲喂普通饲料及高脂高胆固醇饲料,对照组也随机分为2组,分别饲喂以上2种饲料。2周后处死动物,检测血浆中血糖、甘油三酯(TG)及胆固醇(TC)含量,同时进行肾脏组织形态学观察,动物处死前留取24h尿液,检测尿液中白蛋白分泌量。结果:高脂高胆固醇饲料饲喂地鼠2周后,血浆TG极度升高,最高可达14000mg/dL左右,TC达4000mg/dL;对照组地鼠饲喂高脂高胆固醇饲料后TG和TC也明显升高至500mg/dL以上。糖尿病-普通饲料组地鼠肾/体重比、24h尿白蛋白显著增加,但肾脏形态学无显著变化,而喂饲高脂饲料后,糖尿病地鼠肾脏肥大、出现脂质沉积、肾小球系膜细胞增生及系膜基质增多等明显肾脏病理改变。结论:采用高脂高胆固醇饲喂糖尿病地鼠,仅2周出现高脂血症并伴有明显的糖尿病肾病病理改变,为研究糖尿病肾病及其脂代谢的各种机制提供了良好的基础。

消痤Ⅰ号冲剂对金黄地鼠性激素水平与皮脂腺斑组织形态的影响

目的探讨消痤Ⅰ号冲剂治疗寻常痤疮的作用机理。方法选用金黄地鼠侧背部皮脂腺斑作为动物模型,把金黄地鼠随机分成3组,分别用消痤Ⅰ号冲剂、蒸馏水、泰尔丝灌胃,用游标卡尺测量左右皮脂腺斑的最大横径和最大纵径,采集血清检测睾酮、雌二醇的激素水平,观察皮脂腺斑的显微结构。结果3组皮脂腺斑的最大横径×最大纵径的比较无显著差异;消痤Ⅰ号冲剂组较蒸馏水组睾酮水平明显降低;组织形态学也证实,消痤Ⅰ号冲剂组的皮脂腺厚度较蒸馏水组、泰尔丝组薄,排列较松散,液化囊形成数目多。结论消痤Ⅰ号冲剂可抑制皮脂腺的功能,从而影响皮脂腺斑的增生,疗效优于泰尔丝组。

PCNA和bcl-2在金仓鼠胆管癌和胆管细胞增生中的表达

目的 建立肝内胆管癌 (ICC)动物模型 ,观察增殖细胞核抗原 (PCNA)和bcl 2在肝内胆管癌发生发展的病理过程中的表达。方法 60只 6周龄雄性金仓鼠 ,随机分为正常对照组、单纯结扎胆总管组和二异丙醇亚硝胺 (DIPN)组 ,分别在实验的 5、10及 15周分批处死动物 ,观察其形态学变化。免疫组化SABC法检测胆管癌组织和胆管上皮细胞增生中PCNA和bcl 2的表达。结果PCNA标记指数 (PCNALI)在胆管腺癌中最高 ( 78.5 % ) ,不典型增生 ( 5 1.6% )、腺瘤样增生 ( 5 0 .3 % )、胆管肠上皮化生 ( 4 0 .3 % )、小胆管囊性增生 ( 2 5 .5 % )和小胆管增生 ( 2 3 .6% )次之 ,正常胆管上皮 ( 3 .1% )最低 (P <0 .0 1) )。bcl 2在胆管组织癌变过程中的阳性表达率分别是 :正常胆管上皮 3 0 % ( 3 / 10 )、小胆管增生 2 0 % ( 2 / 10 )、肠上皮化生 2 0 % ( 2 / 10 )、腺瘤样增生 40 % ( 4 / 10 )、不典型增生 40 %( 4 / 10 )、腺癌最高 ,为 80 % ( 8/ 10 ) (P <0 .0 5 )。结论 PCNA标记指数在肝内胆管癌和胆管上皮细胞增生中明显高于正常胆管组织 ,提示胆管癌的发生可能是从正常胆管组织到间变 ,再发展为胆管癌 ;抑制细胞凋亡的bcl 2的过表达可能是DIPN诱发的肝内胆管癌发生的重要机制。

茶色素对叙利亚地鼠胚胎正常细胞和癌前细胞生长选择性作用的机制研究

目的利用叙利亚地鼠胚胎细胞(SHE)混合培养模型,研究不同剂量的红茶提取物活性物质茶色素(TP)对SHE正常细胞和癌前细胞生长、增殖、凋亡及相关调控基因表达的影响。方法以0μg/ml的TP为对照组,通过细胞生长实验、原位细胞增殖实验、细胞凋亡实验、Microarray实验来研究不同浓度的TP(0.5、1、5、10和50μg/ml)对单独培养的HE正常细胞和癌前细胞及混和培养模型SHE癌前细胞凋亡、增殖和相关调控基因表达的作用。结果TP促进SHE正常细胞的生长和增殖,对其凋亡没有影响;TP抑制SHE癌前细胞的生长和增殖,促进癌前细胞的凋亡;TP抑制混合培养模型中SHE癌前细胞的生长和增殖,促进其凋亡;TP对于细胞凋亡的调控可能通过Caspase3、Caspase8、p53、bad、bax、GADD45等上调基因及mdm2基因下调来实现;TP对于细胞增殖的调控可能通过阻滞细胞周期G2期实现。结论TP通过促进细胞凋亡直接或者通过促进正常细胞的增殖间接来抑制癌前细胞向肿瘤的转变,这种选择性作用可能与TP的抑癌机制有关。

光照周期对叙利亚地鼠生长发育和繁殖的影响

对离乳雄性叙利亚地鼠（Ｍｅｓｏｃｒｉｃｅｔｕｓａｕｒａｔｕｓ）和雌性叙利亚地鼠各３０只分别给以长光照（１６Ｌ：８Ｄ）、中光照（１２Ｌ：１２Ｄ）和短光照（８Ｌ：１６Ｄ）三种光周期处理，研究光周期对叙利亚地鼠生长发育和繁殖的影响。１３周龄时，短光照处理组雄性地鼠的体重显著（Ｐ＜０．０５）高于长光照和中光照组的体重；雌性地鼠９周龄时长光照组的体重显著（Ｐ＜０．０１）高于另外两个处理组的体重，较高的日食量可能是长光照组具有较大体重的原因之一，雄性地鼠的睾丸、副睾和肾上腺重量及雌性地鼠的卵巢、子宫和肾上腺重量表现了随着光照时间的延长而递增的趋势。长光照条件有利于雌性地鼠的正常发情和繁殖。每天１６ｈ的光照对繁殖地鼠是比较适宜的。

金仓鼠肝内胆管癌中VEGF的表达与血管生成的相关性研究

目的 探讨血管内皮生长因子 (Vascularendothelialgrowthfactor,VEGF)和血管生成在金仓鼠肝内胆管癌发生、发展的关系。方法 应用氨基比林和亚硝酸钠诱导金仓鼠肝内胆管癌 ,免疫组化方法检测标本中VEGF、MVD的表达。结果 VEGF在肝内胆管癌组和实验对照组中的阳性率分别是 78 6 %和 10 0 % ,有明显的统计学意义 (P <0 0 1)。肝内胆管癌中VEGF阳性组MVD值明显高于阴性组 (P <0 0 1)。结论 VEGF与肝内胆管癌的血管生成相关 ,并且促进其生长、侵袭及转移 ,血管生成在肝内胆管癌的形成及生长过程中可能起重要的作用。

DMBA诱发金黄地鼠颊粘膜癌及肉瘤形成的观察

目的 探讨化学致癌剂诱导实验性口腔癌发生过程中结缔组织改变及其肿瘤起源和意义。方法 年轻金黄地鼠, 用0 .5 % DMBA( 二甲基苯) 丙酮液涂抹其右侧颊囊; 对照组仅纯丙酮涂抹或不处理。3 、6 、9 、12 和16 周分批处死动物, 观察诱癌区病理组织学改变; 拟有结缔组织恶变者, 用抗keratin 、vimentin 和desmin 抗体进行免疫组化染色。结果 DMBA 不仅可诱发地鼠颊粘膜上皮癌变, 而且结缔组织也发生了一系列变化: 纤维细胞增殖, 血管增生和炎性细胞浸润等, 约27 % 动物在异常增生上皮下方或癌巢周围出现类似纤维肉瘤或梭形鳞癌的肿瘤细胞, 经免疫组化证实为来自间叶组织的纤维肉瘤。结论 化学致癌剂致癌过程可能存在上皮结缔组织相互作用, 研究结果有助于提高对口腔癌发生生物学及防治策略的认识。

BOP诱导叙利亚仓鼠胰腺癌动物模型建立和相关生物学特性的研究

目的:探讨N-亚硝酸2-双丙基胺[bis-(2-oxopropyl)-N-nitro samine,BOP]诱导建立叙利亚仓鼠胰腺癌动物模型的可行性和建模过程特点,初步分析模型胰腺癌的相关生物学特点,为胰腺癌动物模型研究提供一个可控性强、动态、全面的基础。方法:73只叙利亚仓鼠随机分为实验组和对照组,实验组予以生理盐水稀释成20 mg/ml的BOP按照20 mg/kg体重腹壁皮下注射每周1次,连续4周;相同条件注射生理盐水为对照组。连续监测各组仓鼠体重,注射结束后4周开始每2周依次收集两组叙利亚仓鼠组织标本,观测其形态特点。结果:注射后20周实验组开始出现胰腺肿瘤,注射后28周开始成瘤明显增加,病理观测为低分化腺癌,复种实验成功,部分实验结果与既往报道不一致。结论:BOP可以成功构建叙利亚仓鼠胰腺低分化腺癌动物模型,在注射后第28周后收集标本时间最佳,部分实验结果值得进一步深入研究。

C-fos、K-ras蛋白在肝内胆管癌形成过程中的表达及意义

目的:探讨癌基因产物C-fos、K-ras蛋白与肝内胆管癌发生的关系及其生物学意义。方法:利用氨基比林和亚硝酸钠诱发叙利亚地鼠肝内胆管癌,应用免疫组化方法检测癌变过程中C-fos、K-ras蛋白的表达情况,并应用图象分析技术对免疫组化结果进行半定量分析。结果:C-fos蛋白在胆管增生病变中即出现高表达,随增生程度的加重及肿瘤形成,其阳性表达率和表达强度均逐渐增高,这种高表达状态持续出现于癌变的全过程;而K-ras蛋白高表达仅见于少数不典型增生胆管、胆管腺瘤和腺癌组织中。结论:c-fos癌基因的激活和蛋白高表达是叙利亚地鼠肝内胆管癌发生的早期分子事件,并参与癌变的全过程;k-ras基因的激活及蛋白高表达可能与部分胆管上皮的恶性转化相关。

金黄地鼠胰腺癌动物模型的建立

目的:建立N-Nitrosobis(2-oxopropyl)amine(BOP)诱导性金黄地鼠胰腺癌动物模型。方法:将120只雌性叙利亚金黄地鼠随机分为实验组(80只)和对照组(40只)。按10 mg/kg体重分别给实验组金黄地鼠皮下注射BOP,每周1次,持续7周;对照组皮下注射生理盐水。第1次注射后第11周开始,每两周1次,处死实验组金黄地鼠10只,对照组5只。行组织病理学检查。结果:实验组部分动物出现黄疸及营养不良、远处转移,平均体重轻于对照组,差异有统计学意义(P<0.05)。剖腹肉眼观察,在18只实验组动物中发现23个胰腺肿瘤。其中,1只有3个胰腺肿瘤,3只有2个肿瘤,其余均为单发。其中,7个肿瘤直径<5 mm,16个肿瘤直径≥5 mm,最小肿瘤直径2.0 mm,最大肿瘤直径17 mm。肿瘤直径中位数6.8 mm,体积中位数178.71 mm3,质量中位数0.32 g。组织学检查共在26只实验鼠中发现31个胰腺癌,其中原位癌9个,浸润癌22个,均为胰腺导管腺癌。所有荷瘤鼠均伴有不同程度不典型增生,19周后,所有的实验组动物均发现不典型增生,共在65只实验组动物中发现胰腺不典型增生。实验组总成瘤率81.3%(65/80)。结论:经皮下注射BOP,成功建立诱导性金黄地鼠胰腺癌动物模型,操作方法简单,易复制,组织病理学与人胰腺癌相似,是胰腺癌体内研究理想的动物模型。