n-3多不饱和脂肪酸对大鼠结直肠癌的影响及与脂质代谢相关基因的研究

N- 3polyunsaturated Fatty Acids Effect on Rat's Colorectal Cancer and the Related Gene of Lipid Metabolism

目的探讨n-3多不饱和脂肪酸(n-3PUFAs)对大鼠结直肠癌的影响及与脂质代谢相关基因的研究。方法选取60只SPF级SD大鼠,将大鼠随机分为实验组与对照组,每组各30例。以N-甲基-N-亚硝基脲(MNU)经灌肠方式诱导大鼠大肠癌模型。同时,于建立模型1周前,对照组喂养含葵花籽油饲料(n-6PUFAs),实验组喂养含鱼油饲料(n-3PUFAs),直至16周。处死大鼠并解剖,寻找原发肿瘤并观察周围淋巴结转移情况。将可疑组织进行HE染色,行常规病理学检查。采用气象色谱方法测定无病变结肠组织n-3PUFAs含量。采用RT-PCR方法检测脂质代谢关键调控基因:脂肪酸合成酶(FAS)、环氧合酶2(COX-2)、5-脂氧合酶(5-LOX)和过氧化物酶增殖活化受体(PPARβ及PPARγ)的mRNA表达。结果实验组的肿瘤发生率低于对验组的肿瘤发生率(P<0.05)。实验组无病变结肠组织n-3PUFAs含量高于对照组(P<0.01)。实验组FAS、COX-2、5-LOX和PPARβmRNA的表达低于对照组(P<0.05或P<0.01),实验组PPARγmRNA的表达高于对照组(P<0.01)。结论 n-3PUFA通过影响脂质代谢关键调控基因的表达,起到抗肿瘤的作用。

Objectlve To investigate the effects of n -3 polyunsatumted fatty acids（ n -3PuFAs） on colorectal cancer in SD rats and the related gene of lipid metabolism. Methods Sixty SD rats were randomly divided into control group and experimental group, in which n - 6PUFAs and n - 3 PUFAs were given as treatment, respectively. MNU enema was given in both groups. The pathological observation was performed at the 16th week by HE sections. The n -3PUFAs concentration on normal colon was measured by gas chromatography. The mRNA expression of FAS, COX - 2,5 - LOX, PPARβ and PPARγ were detected by semiquantitative RT - PCR. Results The cancer ratio in experimental group were significant lower than control group（ P 〈 0.05 ） ,while n - 3PUFAs of normal colon organization was higher than the control group（P 〈0.01 ）. The expression of FAS, COX -2, 5 - LOX and PPARβ mRNA was lower than the control group（P 〈0.05 or P 〈 0.01 ）. The expression of PPARγ mRNA in the experimental group was higher than the control group（P 〈 0.01 ）. Conclusion Via regulating the mRNA expression of lipid metabolic gene,n- 3PUFAs prevents the occurrence of colorectal cancer in SD rats.