限食和多不饱和脂肪酸对大鼠结肠炎影响

Effects of polyunsaturated fatty acids with calories restriction on colitis in rats

目的用析因设计方法探讨限食和不同比例的n-6、n-3多不饱和脂肪酸(PUFA)对葡聚糖硫酸钠(DSS)诱导大鼠溃疡性结肠炎作用。方法 SD雌性大鼠48只随机分为对照组、模型组、5∶1常规组(n-6/n-3 PUFA为5∶1)和3个限食组(分别给予正常饲料,添加n-6/n-3PUFA为5∶1和10∶1的饲料,能量为非限食组的60%);喂养14周后,除对照组外,其余各组给予5%DSS溶液自由饮用7 d造模,记录大鼠体重、粪便性状及便血情况;造模结束3 d后,处死大鼠,取结肠评价结肠湿重指数、大体评分和组织病理学评分,并检测血清中髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)含量。结果与模型组比较,5∶1限食组大鼠疾病活动指数(1.14±0.74)无显著变化,血清中SOD、GSH-Px活性[分别为(207.92±21.54)、(393.87±81.60)U/m L]升高(P<0.05),MPO、MDA含量[分别为(157.61±12.56)U/L、(4.91±0.67)nmol/m L]降低(P<0.05),结肠湿重指数[(71.09±4.59)mg/cm]、大体评分、组织病理学评分[分别为(1.57±1.27)、(1.14±0.26)分]降低(P<0.05)。结论膳食中添加n-6与n-3比例为5∶1的PUFA和限食联合作用,对大鼠溃疡性结肠炎有明显保护作用,其机制可能与抗氧化有关。

Objective To explore the effect of different ratios of n-6 and n-3 polyunsaturated fatty acids （PUFA） combined with food restriction on ulcerative colitis induced by dextran sulfate sodium （DSS） in rats. Methods Forty- eight female rats were randomly divided into six groups：control group, model control group, 5：1 regular group （PUFA n-6/n-3 = 5： 1 ）, three calories restriction groups （ PUFA appended： none, n-6/n-3 = 5 ： 1, n-6/n-3 = 10： 1 ; with energy re- striction of 60% ）. All rats were fed with specific diet for 14 weeks. Then the rats in ulcerative colitis model groups were given 5.0% DSS in drinking water for 7 days. Body weight,bloody stools and diarrhea were recorded during the experi- ment. All rats were sacrificed using an overdose of anesthesia 3 days after the establishment of the model. The colon sam- pies were extracted, and the colon weight/length ratio （mg/cm）, overall score and histological score were assessed. The activities of myeloperoxidase （ MPO ）, superoxide dismutase （ SOD ）, glutathione peroxidase （ GSH-Px ）, and content of malondialdehyde（MDA） in serum were detected with biochemistry methods. Results Compared with DSS model con- trol group, the disease activity index（ 1.14 ＋ 0. 74） in the PUFA n-6/n-3 = 5：1 and calories restriction group was not sig- nificantly different（P 〉0. 05） ;the weight/length ratio（71.09 ±4. 59 mg/cm） in the PUFA n-6/n-3 =5：1 and calories restriction group was significantly lower （ P 〈 0. 05 ） ; the overall score （ 1.57 ± 1.27 ） in the PUFA n-6/n-3 = 5： 1 and cal- ories restriction group was significantly lower （P 〈 0. 05 ） ;the histopathological score （ 1.14 ± 0. 26） in the PUFA n-6/ n-3 = 5：1 and calories restriction group was significantly lower （ P 〈 0. 05 ） ; the activity of SOD （ 207.92 ± 21.54 ） and GSH-Px（393.87 ± 81.60） in serum in the PUFA n-6/n-3 = 5：1 and calories restriction group were significantly higher （P 〈 0. 05 ） ;the content of MPO （ 157.61 ± 12. 56） and MDA（4. 91 ± 0. 67 ） in the PUFA n-6/n-3 = 5：1 and calories re- striction group were significantly lower（P 〈 0. 05）. Conclusion The effects of food restriction and PUFA n-6/n-3 = 5：1 in protection of DSS-induced ulcerative colitis are significant and the mechanism may be related to antioxidation.