饮食限制对高血脂小鼠抗氧化能力和Sirt1表达的影响

EFFECTS OF DIETARY RESTRICTION ON ANTIOXIDANT CAPACITY AND SIRT1 EXPRESSION IN HYPERLIPIDEIMA MICE

目的研究饮食限制对高血脂小鼠抗氧化能力和Sirt1(沉默信息调节因子2相关酶1)的影响。方法建立高血脂小鼠模型,随机分高血脂对照组,限食30%组和限食50%组,同时设正常对照组,每组15只小鼠;正常对照组小鼠常规饲养,高血脂对照组小鼠自由摄食高脂饲料,限食30%组和限食50%组小鼠分别按照高血脂对照组平均摄食量的70%和50%饲喂高脂饲料;5 w后,取血液组织,解剖小鼠,取心、肝、脑等组织,测定其中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)等酶活性和总抗氧化能力(T-AOC)及丙二醛(MDA)含量;Western blotting检测肝脏和脂肪组织中Sirt1的表达。结果高血脂对照组小鼠心脏中SOD活性、血浆中CAT活性及心、肝、脑中的T-AOC均显著低于正常对照组(P<0.01或P<0.05),肝脏中MDA含量显著高于正常对照组(P<0.01),而限食30%组小鼠心脏中SOD、CAT活性,血浆中CAT活性,心、脑中T-AOC均显著高于高血脂对照组(P<0.01或P<0.05),MDA低于高血脂对照组;限食50%组小鼠心脏中SOD活性、血浆和肝脏中CAT活性亦均显著高于高血脂对照组(P<0.01);总体评价结果显示,两限食组小鼠SOD活性及限食30%组T-AOC均显著高于高血脂对照组(P<0.01);高血脂对照组小鼠肝和脂肪组织中Sirt1的表达量均降低,而两限食组较高血脂对照组显著升高(P<0.05或P<0.01)。结论饮食限制通过上调Sirt1的表达以增强高血脂小鼠的抗氧化能力。

Objective To explore the effect of dietary restriction on antioxidant capacity and the expression of Sirtl （silent mating type information regulation 2 homolog 1） in mice with hyperlipidemia. Methods The mouse model of hyperlipidemia was established by feeding a high-fat diet for 5 weeks. Then, the mice with hyperlipidemia were randomly divided into high fat diet group （HFD）, 30%-restricted diet group （DR30%） and 50%-restricted diet group （DR50%） with 15 mice in each group. Normal control group （NC） with 15 mice was set up at the same time. The mice in HFD, DR30% and DR50% group were supplied with the high-fat diet and the mice in NC group were supplied with common diet. The mice in HFD and NC group were fed ad libitum, while the mice in DR30% and DR50% groups were supplied with the high-fat diet in about 70% and 50% of the consumption of mice in HFD group respectively. All mice were provided with water ad libitum. Five weeks later, the blood, heart, liver and brain were collected to measure the levels of superoxide dismutase （SOD）, catalase （CAT）, total antioxidant capacity （T-AOC） and malondialdehyde （MDA）. The expressions of sirtl in liver and adipose tissue were measured by Western blotting. Results In HFD group, SOD activity in heart, CAT activity in plasma, T-AOC in heart, liver and brain were significantly lower than those of NC group （P〈0.01 or P〈0.05）, but MDA content of liver was notably higher than that in NC group （P〈0.01）. The SOD, CAT and T-AOC in heart, CAT activity in plasma and T-AOC in brain of the mice in DR30% group were remarkably higher than that of HFD group （P〈0.01 or P〈0.05）. Compared with HFD group, SOD activity in heart, CAT activity in liver and plasma in DR50% group were higher than that of（P〈0.01）.It was indicated that SOD activity in the mice of DR30% and DR50% group, and T-AOC in DR30% group were notably higher than those in HFD group （P〈0.01）. Expression of Sirtl in liver and adipose of HFD group was decreased obviously, but it was increased notably in the mice fed with restricted diet （P〈0.05 or P〈0.01）. Conclusion Dietary restriction can improve antioxidant capacity in mice with hyperlipidemia by up-regulating the expression of Sirtl in liver and adipose.