| Objective: Osteoporosis is a disease of bone metabolism of the whole human body. The bone mineral density is lower and the structure of bone is changed .In osteoporosis patients, in addition, the risk of fracture is higher for the bone toughness of the patients is decreased. At present, osteoporosis is common in old people and menopause woman. Its incidence increases with aging, 20% in man, 50% in menopause women.There are two kinds of osteoporosis in general: original contracted osteoporosis and contracted osteoporosis due to other diseases. There are two types of the first kind: post-menopausal osteoporosis ( I) and aging osteoporosis (II). There are three kinds of medines used for the treatment of osteoporosis: first group, those which can inhibit the bone absorbing process, such as E2, nilestriol, CT, etc. The second group are those which can promote bone forming , such as Tridin, PTH etc. The last group consist of the medicines which can benefit the mineral deposit process, such as alfacalcidol, caltrate D600 etc.Much attention is paid to post-menopausal osteoporosis because its cause is clear, that is, due to lower estrogen level in the body. Estrogen replacement therapy (ERT) is widely used in preventing post-menopausal osteoporosis. But, this method may increase the risk of developing breast cancer . Many women do not like it. So, to explore a new medicine is of importance.Phytoestrogens are some compounds obtained from plants, Structurally, they share many similarities with endogeneous estrogens, they can bind to estrogen receptors, and they may exert both estrogenic and antiestrogenic effects depending on circulating levels of endogenous sex hormones. Soybean isoflavones are compounds obtained from soybean.They exhibit weak estrogenic activity on the order of 10~2-10~3 that of 17 beta -estradil ; but may be present in the body in concentrations 100-fold higher than endogenous estrogens. But they have little side effects . They have been shown to be effective in promoting bone mass and preventing bone loss.Ligant and coumarins are also phytoestrogens. Some traditional Chinese medicines contain those compounds. According to Chinese medicine, " kidney controls the bone". And those medicines are tonifying kidney recipe. Maybe those compounds have some effects on bone.Based on the above theories, the effects of phytoestrogen, particularly isoflaveones, on osteoporosis in ovariectomized rats and their mechanisms were studied.Method: Six-month SD femate rats were divided randomly into 5 groups: (1) SHAM group (control group); (2) OVX (ovarectomy); (3) H-ISO (ovx+soy isoflavones 30 mg ·kg-1) ; (4) L-ISO (ovx+soy isoflavones 15 mg · kg-1); (5) E2 (ovx+nilestriol).Tibia and femur bone mineral density (BMD) of rats were measured by using dual-energy X-ray absorptiometry.ALP, BALP were measured to observe the effects of soy isoflavones on the bone builting process. To observe the effects on the bone resorping process, Ca/Cr, HOP/Cr and TRACP were measured.The level of serum E2 and BGP were measured by RIA. RT-PCR and immunohistochemistry were used separately to semi-quantify the amount of collagen type I of rat femur and osteoblasts to observe the changes caused by soy isoflavones.MTT and PNPP were used separately to observe the proliferationand the activity of ALP of osteoblasts cultured in vitro with soy isoflavones( such as Genistein, Daidzein), or lignans ( such as deoxyschizandrin andgamma-schizandrin ) or coumarins (such as osthol) of different concentrationin it for different incubation periods .The whole experiments consist of 5 parts:1 The preventive effects of soybean isoflavones on ovariectomized rat osteoporosisSix-month SD femate rats were divided randomly into 5 groups: (1) SHAM group (control group); (2) OVX (ovarectomy); (3) H-ISO (ovx+soy isoflavones 30 mg·kg-1); (4) L-iso (ovx+soy isoflavones 15 mg·kg-1); (5) E2 (ovx+nilestriol).Animals in the SHAM group were subject to sham operation .Ovariectomies were performed in other gr... |
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