大豆异黄酮对去势大鼠脂质过氧化及肝超微结构的影响

目的 研究大豆异黄酮(soybean isoflavone,SI)对去势大鼠脂质过氧化及肝超微结构的影响.方法 70只雌性SD大鼠按血清总胆固醇水平随机分为7组:高脂、雌激素,低、中、高剂量SI干预、假手术及正常对照组.前5组摘除双侧卵巢,恢复1周后开始干预,实验周期为12周,灌胃给药,每周称重1次,分别在去卵巢、给药4、8周、处死时抽取尾静脉血,实验结束后取肝脏标本,分别测定胆固醇(TC)、甘油三酯(TG)、血清高、低密度脂蛋白胆固醇(HDL-C、LDL-C)、脂蛋白(a)及抗氧化酶活性等.结果 SI干预组LDL-C水平显著低于高脂组但仍高于正常对照组;干预可使脂蛋白(a)水平发生变化但对HDL-C影响不显著;高剂量SI能缓解因去卵巢造成的肝细胞超微结构破坏,维护其完整性,全视野下以高剂量干预组与正常组结构最为接近,高脂组镜像损坏明显.结论 SI对去卵巢大鼠的脂蛋白(a)、脂质过氧化及肝超微结构存在影响,高剂量持续干预能降低去卵巢大鼠的LDL-C,并能维持肝超微结构.

THE EFFECT OF SOYBEAN ISOFLAVONE ON LIPID PEROXIDATION AND LIVER ULTRASTRUCTURE IN OVARIECTOMIZED RATS

Objective To study the effects of soybean isoflavone(SI) on lipid peroxidation and liver ultrastructure in ovariectomized rats. Methods Seventy female Sprague-Dawley(SD) rats were randomly divided into 7 groups according to the levels of total cholesterol(TC) in serum: hyper-lipoid group,estrogen group,low-dose SI group,middle-dose SI group,high-dose SI group,sham group and normal control group.After bilateral ovaries were extirpated except sham and normal control groups for a week,the estrogen,different doses of SI or deionized water were fed with intragastric administration for 12 weeks.The rat body weight was weighted once per week and blood samples were collected at the time of ovariectomization,the 4th and 8th weeks after administeration at the time of being killed.The serum TC,triglyceride(TG),high or low density lipoprotein-cholesterol(HDL-C,LDL-C),lipoprotein(a) and antioxygen enzyme were assayed. Results LDL-C levels in SI intervention groups were significantly lower than that in hyper-lipoid groups but higher than that in normal control group;the levels of lipoprotein(a) were changed;there was almost no effect on HDL-C in serum.SI could retain integrity and ultrastructure of hepatocyte;there was similar structure in high dose SI group and normal control group.An obvious damage was detected in hyper-lipoid group.Conclusion SI can improve lipoprotein(a) and lipid peroxidation in ovariectomized rats.A continuous intervention with high-SI can reduce LDL-C to normal lever and retain integrity and ultrastructure of hepatocyte.