孕期补充二十二碳六烯酸对子代大鼠脂肪代谢及解偶联蛋白2基因表达的影响

EFFECTS OF SUPPLEMENTATION WITH DOCOSAHEXAENOIC ACID DURING PREGNANCY ON LIPID METABOLISM AND UNCOUPLING PROTEIN 2 GENE EXPRESSION IN OFFSPRING

目的探讨孕期补充二十二碳六烯酸(DHA)对子代脂肪代谢和解偶联蛋白2基因表达的影响。方法将SD雌鼠按体重随机分成A、B、C三组,孕期分别食用基础膳食(A)、补充低剂量DHA膳食(B)、补充高剂量DHA膳食(C)。所产雄性仔鼠均由A组母鼠哺乳,21d断乳,用基础膳食喂饲至出生后的第8w。将A组仔鼠按体重随机分为正常对照组A1、高脂对照组A2,A1组继续食用基础膳食至实验结束,A2、B、C三组给予高脂膳食喂饲7w,结束实验。在第8w、15w时各组随机选取8只仔鼠处死,观察体重、体脂含量、血脂和白色脂肪UCP2mRNA表达丰度变化。结果各组仔鼠出生体重和出生后第8w体重均无差异(P>0.05)。第8w时B、C组仔鼠体脂含量、血清甘油三酯水平显著低于对照组(P<0.05);第15w时,A2组体重、体脂含量、甘油三酯均显著高于A1组(P<0.05),B、C两组体重和血清甘油三酯水平显著低于A2组(P<0.05)。第8w时,B、C两组大鼠白色脂肪组织UCP2mRNA水平均高于A组;15w时,UCP2mRNA水平依次为C组高于B组、A1和A2组,A2组最低。结论孕期适量DHA补充可降低子代大鼠摄取高脂肪膳食时的体重、血清甘油三酯,即降低肥胖发生风险,改善脂肪代谢;其中对子代白色脂肪组织UCP2基因表达的上调作用可能是其潜在机制之一。

Objective To investigate the effect of the maternal rats supplemented with docosahexaenoic acid （DHA） during pregnancy on lipid metabolism and uncoupling protein 2 gene expression of offspring. Method Female SD rats were randomly divided into A,B,C groups by weight. Group A was fed with basic diet. Group B and C were supplemented with low and high dose of DHA during pregnancy respectively. All male offspring were suckled by rats in group A,and fed with basic diet from weaning （3 w） to 8 w. Then the offspring from group A were randomly divided into A1 and A2 subgroup. A1 was fed with basic diet continuously,while rats from A2,B,C groups were assigned to high-fat diet for 7 w to induce obesity. Eight rats from each group were selected randomly and sacrificed at 8,15 w. Body weight,body fat,blood lipid and uncoupling protain 2 （UCP2） mRNA level were measured. Results There was no difference in the birth weight and body weight of offspring in A,B,C groups （P〉0.05） at 8 w. At 8 w body fat and TG in groups B and C were significantly lower than group A （P〈0.05）. At 15 w,the body weight,body fat and TG in group A2 were significantly higher than group A1（P〈0.05）,while TG in groups B and C were significantly lower than group A2 （P〈0.05）. At 8 w,the abundance of UCP2 mRNA in groups B and C were higher than group A. At 15 w,the UCP2 mRNA level in C group was higher than B,A1 and A2 successively,A2 was the lowest. Conclusion Supplementation with DHA during pregnancy could decrease the body weight and serum TG level in offspring,and may prevent offspring from high fat-induced obesity and improve lipidmetabolism in adulthood. Up-regulation of the expression of UCP2 mRNA may be the underlying mechanism.