高脂饮食对大鼠结肠腺瘤形成的影响

Effects of high-fat diet on the formation of colorectal adenomas in rats

目的了解高脂饮食对大鼠结肠腺瘤发生的影响。方法20只Wistar大鼠均分为2组，一组给予普通饮食，一组给予高脂饮食；两组大鼠连续10周每周腹腔注射1次1，2-二甲基肼（DMH）（每次40 mg/kg），普通饮食＋DMH为SDT组，高脂饮食＋DMH为HFDT组。免疫组织化学法检测Ki-67表达。免疫荧光检测增殖细胞核抗原（PCNA）和环氧合酶的2表达。ELISA法检测两组大鼠血清三酰甘油、胆固醇、胰岛素样生长因子-1（IGF-1）、胰岛素、瘦素和TNF-α水平。统计学方法采用Student t检验或Mann-Whitney检验。结果SDT组和HFDT组大鼠第18周（腺瘤期）时Ki-67阳性细胞数分别为24.00±1.84和75.17±3.17，差异有统计学意义（t＝13.960，P〈0.01）。SDT组和HFDT组大鼠PCNA平均荧光强度分别为213.70±21.61和333.30±30.44，差异有统计学意义（t＝4.987，P〈0.01）。SDT组和HFDT组大鼠血清三酰甘油分别为（0.43±0.05）和（1.14±0.07） mmol/L，差异有统计学意义（t＝8.366，P〈0.01）；胆固醇分别为（3.75±0.26）和（7.77±0.79） pmol/L，差异有统计学意义（t＝4.851，P〈0.01）。结论高脂饮食能够通过影响机体的内分泌代谢变化、增进细胞增殖周期、介导炎性反应促进结肠腺瘤的发生、发展。

Objective To investigate the effects of high-fat diet on the formation of colorectal adenomas in rats. Methods Twenty Wistar rats were evenly divided into two groups, one group were fed with common food and the other group were fed with high fat-diet. The rats of two groups were intraperitoneally injected with 1,2-dimethyl-hydrazine （DMH） （40 mg/kg） once a week for 10 consecutive weeks. Rats with common diet and DMH were assigned to SDT group,and those with high-fat diet and DMH were assigned to HFDT group. The expression of Ki-67 was detected by immunohistochemistry and the expression of proliferating cell nuclear antigen （PCNA） and cyclooxy-genase 2 （COX2） was detected by immunofluorescence. The levels of serum triglyceride, cholesterol, insulin like growth factor-1 （IGF-1）, insulin, leptin and tumor necrosis factor-α were determined by enzyme linked immunosorbent assay. Student＇s t test and Mann-Whitney test were performed for statistical analysis. Results At the 18th week, the numbers of Ki-67 positive cells of SDT group and HFDT group were 24.00±1.84 and 75.17±3.17, respectively, and the difference was statistically significant （t= 13. 960, P〈 0.01）. The fluorescence intensity of PCNA of SDT group and HFDT group was 213.70±21.61 and 333. 30± 30.44, respectively, and the difference was statistically significant （t=4. 987, P〈0.01）. The levels of serum triglyceride of SDT group and HFDT group were （0. 43 ± 0. 05） mmol/L and （1.14±0. 07） mmol/L, respectively, and the difference was statistically significant （t=8. 366, P〈0. 01）. The levels of cholesterol were （3.75±0.26） pmol/L and （7.77±0. 79） pmol/L, respectively, and the difference was statistically significant （t=4. 851, P〈 0. 01 ）. Condusion High-fat diet can promote the genesis and development of adnomas through influencing the body＇s endocrine metabolism, increasing cell proliferation cycle and regulating inflammatory reaction.