大豆异黄酮对去卵巢大鼠脂类代谢及心肌超微结构影响的研究

EFFECT OF SOYBEAN ISOFLAVONE ON LIPID METABOLISM AND MYOCARDIAL ULTRAMICROSTRUCTURE IN OVARIECTOMIZED RATS

目的研究大豆异黄酮(SI)对去卵巢大鼠血脂及脂蛋白(a)[Lp(a)]代谢的动态影响。方法70只雌性SD大鼠按血清总胆固醇(TC)水平随机分为7组高脂组、雌激素组、SI低、中、高剂量组,假手术与正常对照组,前5组摘除双侧卵巢。除正常对照组外,其余各组给予高脂饲料饲养。每周称重一次,灌胃给药,干预周期为12w。对收集的血清、内脏进行TC、甘油三酯(TG)、血清高、低密度脂蛋白胆固醇(HDL-C、LDL-C)、Lp(a)、抗氧化酶活性及内脏超微结构观察,共63只大鼠完成实验。结果SI干预组LDL-C水平显著低于高脂组而高于正常对照组;干预可改变Lp(a)水平但对HDL-C影响甚微;持续干预SI有助于降低TC、TG可维护心肌细胞的超微结构,镜下视野以雌激素组、高剂量SI干预组与正常组结构接近,高脂组镜像损坏明显。结论高剂量SI持续干预可使去卵巢高脂大鼠LDL-C、TC、TG下降,并能维护心肌细胞超微结构。

Objective： To study the effects of soybean isoflavone （SI） on metabolism of lipids and lipoprotein （a） [Lp（a）] in ovariectomized rats. Methods. Senventy female Sprague- Dawley （SD） rats were randomly divided into 7 groups according to the levels of total cholesterol （TC） in serum： high-lipid （HF） group, estrogen （EG） group, low-dose SI （L-SI） group, middle-dose SI （M-SI） group, high-dose SI （H-SI） group, sham group and normal control （NC） group. One week after bilateral ovaries were extirpated, except sham and NC group, estrogen, different doses of SI or deionized water were fed i.g. for 12 w. Except NC group, the other groups were fed high fat diet. Body weights were weighed every week and blood and heart were collected at the end of experiment. The serum TC, triglyceride（TG）, high or low density lipoprotein-cholesterol （HDL-C, LDL-C）, Lp （a）, and antioxidative enzymes activities were assayed. Results： After SI intervention, the levels of LDL-C in SI groups were significantly lower than in HF group but higher than in NC group. The levels of Lp （a） were also changed, but there was almost no effect on HDL-C. Persistent intervention with SI can reduce TC, TG, and protect cadiocyte＇s actin filament and mitochondrial ultramicrostructure from damage as shown in HF group. The ultramicroscopic pictures in EG and H-SI group almost resembled NC group. Conclusion： Persistent intervention of high-dose SI can reduce the levels of LDL-C, TC, TG and protect the myocardiac damages due to high fat diet in ovariectomized rats.