抗性淀粉对氧化偶氮甲烷诱导的大鼠结(直)肠癌前病变预防作用研究  

STUDY OF PROPHYLACTIC EFFECT OF RESISTANT STARCH ON PRECANCEROUS LESIONS OF AZOXYMETHANE-INDUCED COLORECTAL CANCER IN RATS

作　　者：孟妍[1] 陈立勇[1] 

机构地区：[1]山东大学附属省立医院营养科,济南250021

出　　处：《营养学报》2013年第2期158-161,166,共5页Acta Nutrimenta Sinica

基　　金：山东省科技发展计划项目(No.2012GSF11833)

摘　　要：目的研究抗性淀粉(resistant starch,RS)对大鼠结(直)肠癌前病变的预防作用。方法将50只雄性Wistar大鼠随机分为阴性对照、阳性对照组及RS低、中、高剂量组。阳性对照组大鼠从实验第2w开始腹腔注射氧化偶氮甲烷(azoxymethane,AOM),1/w,连续2w。阴性对照组注射生理盐水。各剂量组用致癌剂处理与阳性对照组,并分别自由摄食含7.6%、15.2%及22.8%RS的饲料。对照组大鼠摄食普通饲料。于首次注射AOM后13w断头处死各组所有动物,观察并计数结肠变性隐窝病灶(aberrant crypt foci,ACF)发生情况。并取大肠组织标本,包埋后做石蜡切片,用SABC免疫组化法测量生物标记物增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)标记指数(PCNA-LI)、核仁组成区嗜银蛋白(argyrophilic nucleolar,organizer region protein,AgNORs)颗粒数目,以及Bcl-2蛋白(B-cell lymphomaleukemia-2,Bcl-2)、Bax蛋白(Bcl-2 associated X protein,Bcl-2)表达情况。结果与阳性对照组相比,各RS处理组ACF数目和AgNORs数目均显著降低(P<0.01),高剂量组增殖细胞核抗原标记指数(PCNA-LI)显著减少(P<0.05);此外,RS还抑制了Bcl-2蛋白的表达,诱导了Bax蛋白的表达。结论短期RS对AOM诱发的大鼠结(直)肠癌前病变具有预防作用,可使ACF和AgNQR3显著减少即其机制可能与抑制细胞增殖和诱导细胞凋亡有关。[营养学报,2013,35(2):158-161,166]Objective To study the prophylactic effect of resistant starch （RS） on precancerous lesions of colorectal cancer in rats. Methods A total of 50 male Wistar rats was randomly divided into 5 groups, negative control group, positive control group and three different dose RS groups fed the diets with 7.6%, 15.2% and 22.8% RS. The rats in the positive control group were subcutaneously injected with azoxymethane （AOM） once a week at the second and third week. The rats in the negative control group were injected with saline. The rats in different dose RS groups were given the same treatment as the positive control group and received the corresponding doses of RS. The rats in the control groups were fed a normal diet. All rats were killed on the 16th week. The colons of rats were removed to determine the aberrant crypt foci （ACF） index. The specimens of large intestine tissues were taken for pathological sections. Some biomarkers （such as proliferating cell nuclear antigen （PCNA）, argyrophilic nucleolar organizer region proteins （AgNORs）, B-cell lymphoma leukemia-2 （Bcl-2） and Bcl-2-associated X protein （Bax） were determined by immunohistochemical method. Results Compared with the positive control group, the numbers of ACF and AgNORs in the three RS groups were obviously reduced （P〈0.01）. PCNA - LI of high dose RS group was significantly decreased （P〈0.05）. In addition, RS inhibited the expression of Bcl-2 and enhanced the expression of Bax. Conclusion Resistant starch （RS） has prophylactic effect on precancerous lesions of AOM-induced colorectal cancer in rats. The mechanism may be related to the inhibition of cell proliferation and induction of cell apoptosis.

关 键 词：抗性淀粉 结直肠癌 变性隐窝病灶 氧化偶氮甲烷 细胞凋亡 

分 类 号：R735.3[医药卫生—肿瘤]