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背景:随着国内人民生活水平的不断提高,大肠癌的发生率不断提高。大量的流行病学调查表明,膳食因素与大肠癌的高发有着密切的相关性。目的:通过建立大鼠大肠癌的动物模型,观察膳食纤维与肌醇六磷酸(植酸)对大肠癌发生的作用。设计:随机区组设计。单位:青岛大学医学院营养学研究所。材料:实验于2004-03/12在青岛大学医学院营养学研究所进行。将86只4周龄雄性Wistar大鼠按体质量随机区组分为纤维素组(14只)、果胶组(14只)、植酸组(15只)、纤维素+植酸组(14只)、果胶+植酸组(14只)和对照组(15只)6组。方法:对照组:无膳食纤维的基础饲料;果胶组:添加10%的果胶;纤维素组:添加10%的纤维素;植酸组:添加2%的植酸钠饮水;果胶+植酸组:添加10%的果胶和2%的植酸钠饮水;纤维素+植酸组:添加10%的纤维素和2%的植酸钠饮水。对86只大鼠用1,2-二甲肼皮下注射诱发大肠癌,观察大鼠大肠肿瘤的发生率、肿瘤的数量及体积;测定大鼠大肠粘膜细胞的增殖活性(增殖细胞核抗原阳性细胞数/计数的细胞核总数)。主要观察指标:①各组大鼠大肠肿瘤的发生率,平均每只鼠的肿瘤个数和肿瘤体积变化。②大鼠大肠黏膜细胞的增殖活性。结果:①各组大鼠多死于喂养20周前。果胶组、果胶+植酸组及对照组各有1只大鼠死于喂养20周后。②各组大鼠大肠肿瘤的发生率与对照组相比差异无显著性(P>0.05),但植酸组平均每只鼠的肿瘤个数和肿瘤体积显著低于对照组数量:(1.1±0.2),(4.1±1.2)个/只,P<0.01;体积:(176.1±65.5),(1046.7±469.0)mm3,P<0.05,果胶组、果胶+植酸组平均每只鼠的肿瘤个数显著高于对照组(7.5±1.9),(7.2±1.0)个/只,P<0.05。③植酸组大鼠大肠黏膜细胞的增殖活性比对照组显著降低,果胶组大鼠大肠黏膜细胞的增殖活性比对照组升高(41.8±4.7)%,(83.6±2.9)%,(66.7±7.8)%,P<0.01和0.05。结论:膳食中添加果胶能增加诱癌大鼠患大肠肿瘤的危险,而饮水中添加2%的植酸可降低诱癌大鼠患大肠肿瘤的危险。
Background: With the continuous improvement of people’s living standard in our country, the incidence of colorectal cancer is continuously increasing. A large number of epidemiological studies have shown that dietary factors and the high incidence of colorectal cancer are closely related. OBJECTIVE: To observe the effect of dietary fiber and phytate (phytate) on the development of colorectal cancer by establishing a rat model of colorectal cancer. Design: Random block design. Unit: Institute of Nutrition, Qingdao University School of Medicine. MATERIALS: The experiment was performed at Institute of Nutrition, Qingdao University Medical College from March to December 2004. Eighty - four male Wistar rats of 4 weeks old were randomly divided into four groups according to body weight: cellulose group (14), pectin group (14), phytic acid group (15), cellulose + phytic acid group Only), pectin + phytic acid group (14) and control group (15) 6 groups. Pectin group: add 10% pectin; cellulose group: add 10% cellulose; phytic acid group: add 2% sodium phytate drinking water; pectin + Phytic acid group: add 10% of pectin and 2% of sodium phytate drinking water; cellulose + phytic acid group: add 10% of cellulose and 2% of sodium phytate drinking water. To 86 rats with subcutaneous injection of 1,2-dimethyl hydrazine induced colorectal cancer, the incidence of colorectal cancer in rats, the number and volume of tumors; the proliferation of rat colorectal mucosa (proliferating cell nuclear antigen-positive cells / Count the total number of nuclei). MAIN OUTCOME MEASURES: ① The incidence of colorectal tumors in each group, the average number of tumors per mouse and tumor volume changes. ② rat colorectal mucosal cell proliferation activity. Results: ① rats in each group died more than 20 weeks before feeding. One pectin group, one pectin + phytic acid group and one control group each died after feeding for 20 weeks. ② The incidence of colorectal tumor in each group was not significantly different from that in control group (P> 0.05), but the average number of tumor and tumor volume per rat in phytic acid group was significantly lower than that in control group (1.1 ± (P <0.01); volume (176.1 ± 65.5), (1046.7 ± 469.0) mm3, P <0.05, P <0.05) The number of tumor was significantly higher than that of the control group (7.5 ± 1.9), (7.2 ± 1.0) / only, P <0.05. (3) The proliferative activity of mucosal cells in the phytate group was significantly lower than that in the control group. The proliferative activity of mucosal cells in the pectin group was (41.8 ± 4.7)%, (83.6 ± 2.9)%, (66.7 ± 7.8%), P <0.01 and 0.05. Conclusion: Adding pectin to diet can increase the risk of developing colorectal cancer in cancer-inducing rats. However, adding 2% phytic acid in drinking water can reduce the risk of developing colorectal cancer in rats.