多不饱和脂肪酸对小鼠瘦素表达的影响

EFFECTS OF POLYUNSATURATED FATTY ACIDS ON LEPTIN EXPRESSION IN MICE

目的探讨多不饱和脂肪酸(PUFAs)对瘦素表达的影响。方法使用4w龄C57BL/6J雌性小鼠,分别给予不同种类高脂饲料(18%脂肪,供能比为36%)喂养-高脂豆油饲料、高脂鱼油饲料和高脂豆油:鱼油(5:1)混合饲料,以正常饲料(6%脂肪来自豆油,供能比为12%)为对照,小鼠自由进食,喂养时间为4个月。同时进行了PUFAs对体外培养3T3-L1细胞分化的干预实验,在细胞被诱导分化D5,在培养基中分别加入油酸(OA,C18:1n-9)、花生四烯酸(AA,C20:4n-6)、二十碳五烯酸(EPA,C20:5n-3)和二十二碳六烯酸(DHA,22:6n-3,0.125mmol/L)培养12h。采用酶联免疫吸附试验(ELISA)观察小鼠血浆和细胞培养基中瘦素及瘦素受体(sOB-R)表达的变化。结果鱼油组、豆油:鱼油组以及豆油组之间血浆瘦素水平(15.97±1.41,10.37±0.98和5.81±2.95μg/L)均存在显著性差异(鱼油>豆油:鱼油>豆油);与正常对照组(14.96±6.62μg/L)比,鱼油组血浆瘦素水平未发生明显变化。血浆sOB-R水平在4组饲料之间未见显著性差异。细胞培养显示,与对照组(18.70±0.67μg/gprot)比,在培养基中加入EPA和DHA后瘦素表达量(30.19±7.11和28.18±4.87μg/gprot)明显增多;而加入OA和AA对瘦素表达(19.75±6.11和24.48±9.84μg/gprot)无影响。值得注意的是,未能检测到细胞培养基中sOB-R的表达。结论饲料PUFAs对小鼠瘦素表达具有调节功能,但鱼油n-3PUFAs和豆油n-6PUFAs的作用不同。

Objective To investigate the effects of polyunsaturated fatty acids （PUFAs） on expression of leptin and soluble leptin receptor （sOB-R）. Method Four-week-old C57BL/6J female mice, that had free access to food, were fed three different high-fat （18% by weight supplying 36% of total energy） diets： soy oil, fish oil and soy：fish oil （5：1） respectively with normal chow diet （6% of fat as soy oil supplying 12% of total energy） as control for 4 months. Meanwhile, 3T3-L1 cells were used and incubated respectively with arachidonic acid （AA, C20：4n-6）, eicosapentaenoic acid （EPA, C20：5n-3）, docosahexaenoic acid （DHA, 22：6n-3） and oleic acid （OA, 18：1n-9, 0.125 mmol/L） for 12 h at 5 d after differentiation. Then, blood and cell culture media were collected and leptin and sOB-R in them were measured by enzyme-linked immunosorbent assay. Results Differences were found in plasma leptin levels among three groups of mice fed high-fat diets （fish oil： 15.97±1.41〉soy：fish oil： 10.37±0.98〉soy oil： 5.81±2.95 μg/L ）, Compared to normal chow diet, fish oil diet did not change mouse plasma leptin concentration. Plasma sOB-R levels in four groups were similar. Culture of 3T3-LI cells showed that addition of EPA and DHA to the media increased leotin concentrations （ 30.19 ±7.11 and 28.18±4 .87 μg/g prot） as compared with control （18.70±0.67 μg/g prot）, whereas OA and AA did not change leptin expression （19.75±6.11 and 24.48±9.84 μg/g prot）. No sOB-R expression was detected in all four groups. Conclusion PUFAs in diet can regulate leptin expression in mice, and the regulatory effects are different between fish oil n-3 PUFAs and soy oil n-6 PUFAs.