Effects of soy extract on energy balance in ovariectomized rats

Jifeng WANG; Jianzhao NIU; Lianqi LIU

ABSTRACT

BACKGROUND:

Ovariectomized animals usually are employed for the study of women osteoporosis while little is known about theenergy balance of ovariectomized animals. Many previous studies showed that soy isoflavone could decrease the hyperlipemia resulted by high-fat feed, and how about the effect of soy isoflavone on the energy metabolism in ovariectomized animals?

OBJECTIVE:

To explore the pathologic effect of soy extract and its active components on the energy metabolism in ovariectomized rats so as to provide adequate evidences for the primary rehabilitation and prevention of type Ⅱ diabetes mellitus, disturbance of lipid metabolism as well as hypertension and coronary atherosclerotic heart disease.

DESIGN:

A randomized and controlled trial with the experimental animals as subjects.

SETTING:

Laboratory of Cell and Biochemistry in a university.MATERIALS Ninety Wistar rats (SFP grade, license code scxk11-00-006) were randomized into 9 groups normal group, sham group,model group, estrogen group, high-dose soy flavone group, low-dose soy flavone group, high-dose soy extract group, low-dose soy extract group and soy polysaccharide group, with 10 rats in each group.INTERVENTION Except the rats in normal group and sham group,the bilateral ovaries of other rats were all removed. From one week after operation, body weight and daily food intake were detected once a week.Six weeks later, the rats were killed to calculate the forage transformation efficiency, measure body length, work out the body mass index (BMI),and separate the abdominal fat and weight.MAIN OUTCOME

MEASURES:

①Effect of soy extract on the abdominal fat accumulation of ovariectomized rats. ②Effect of soy extract on food intake of ovariectomized rats. ③Effect of soy extract on forage transformation efficiency of ovariectomized rats.

RESULTS:

After ovariectomy, the food intake, body weight and BMI all raised, and the forage transformation efficiency increased, with abdominal fat accumulation. The changes of energy metabolism induced by ovariectomy were all weakened at different degrees in estrogen group, soy extract group and soy flavone group, while no influenced was found in soy polysaccharide group.

CONCLUSION:

The ovariectomized rats can be used as animal model of the climacteric fat women. The soy extract, with the effective component of flavonoid, can reduce the pathologic changes such as the increase of food intake, body weight and forage transformation efficiency induced by ovariectomy.