The Effect Of Moderate Treadmill Exercise On Blood-lipid Level And Liver Lipids, PPARγ And GSK-3β In Ovariectomized Rats

Beacause of the reduction in intetnal estrogen, menopause easily results in metabolism disorders of glucose and lipid as well as abnormal distribution of body fat. All of these changes are the cause of cardiovascular diseases, nonalcoholic fatty liver disease, central afiposity, diabetes and osteoporosis. The purpose of the present study was to determine the effect of moderate treadmill exercise on blood-lipids (total cholesterin,Triacylflycerol, Low density lipoprotein cholesterol and High density lipoprotein-cholesterol) level,liver and bone lipids (Cholesterol,Triacylflycerol), protein expression of Peroxisome proliferators-activate receptor-γ(PPAR-γ) and Glycogen synthase kinase-3β(GSK-3β) in bone of the ovariectomized Rat.Methods:Three-month-old female Sprague-Dawley rats (80) were divided randomly into four groups:sham operation (20), ovariectomized (OVX,20), OVX with exercise treatment (OVX+EX,20) and OVX supplemented with 17β-estradiol (OVX+E2,20) after adaptive feeding one week. The Ovary of ovariectomized rat was ablated in the back and fat near ovary was resected in the sham operation rat. One week after the surgery, the exercise rats were trained for 55min at a speed of 18 m.min-1 with 5% slope five times a week. The rats in OVX+E2 group were subcutaneously injected 17β-estradiol two times a week, at a dose of 25ug/kgBody weight. At 7 or 15 weeks of ovariectomized, intra-abdominal fats and liver weight were weighted. The liver and bone lipid(cholesterol and triacylglycerol)content was determined by methanol/chloroform.Protein expreesion of Peroxisome proliferators-activate receptor-γ(PPAR-γ) and Glycogen synthase kinase-3β(GSK-3β) in liver was mesured through western-blotting.Results:(1) At the 7th week after ovariectomy, blood lipids had no changes, but TG/HDL rised significantly and was controlled by exercise.The liver content of TG was higher significantly as compared with sham group, but the liver content of TC was not changed. After treatment with exercise, both the liver CHO and TG were significantlylower as compared with OVX group. but only TG had significantly (p<0.01) changed after treatment with E2. At the 15th week after ovariectomy, level of blood TC、LDL、TG/HDL and liver CHO, TG content were significantly higher in OVX group than that of in Sham group. After treatment with exercise or E2, blood TC and the liver lipid content decreased significantly as compared with OVX group, but only blood TC and liver lipid (TG and CHO) had significantly changed after treatment with E2·(2) Compared with the shame group at the 15th week, the lower end of femur and upper end of tibia content of TG in OVX ascended significantly and was reversed after treatment with exercise or E2. (3) At the 7th and 15th week, liver P-GSK-3β/GSK-3β�'�PPARγwas higher significantly as compared with sham group, the protein expression decreased significantly after treatment with exercise or E2.Conclusion:Moderate treadmill exercise could decrease the content of blood, liver and bone lipids, increase protein expression of liver P-GSK-3β/GSK-3βand PPAR-γin ovariectomized rats and its effect was more rapid than E2 treatment.