estradiol-3-benzoate and Osteoporosis

To investigate the influence of parathyroid hormone and estrogen on alveolar bone metabolism of castrated female rats.. Sixty-six female Wistar rats which were healthy and 4 months old were divided into two groups, with group SHAM (n = 18) and group ovariectomy (OVX) (n = 48). After 8 weeks of ovariectomy, the osteoporosis model was confirmed by examing 8 ovariectomized and sham-operated rats. The rest 10 rats in group SHAM were the control group (group A). The rest 40 rats in group OVX were divided into ovariectomized group (group B), ovariectomized and treated with estrogen (group C), ovariectomized and treated with parathyroid hormone (group D), ovariectomized and treated with estrogen and parathyroid hormone (group E) at random with 10 in each group. Group A and B injected physiological saline (1 mL x kg(-1)), group C injected estradiol benzoate (10 microg x kg(-1)), group D injected parathyroid hormone (20 microg x kg(-1)), group E injected parathyroid hormone (20 microg x kg(-1)) and estradiol benzoate (10 microg x kg(-1)). The intraperitoneal injection were maken every other day to rats in each group, which continued for 8 weeks. The bone mineral density (BMD), bone histomorphology and serum Ca, P, alkaline phosphatase (ALP) were measured after therapy.. After 8 weeks of ovariectomy, the lumbar BMD of ovariectomized rats were significantly declined compared with those of the sham-operated rats (P < 0.05). Eight weeks later after the drug use, the BMD, %Tb.Ar, Tb.Th, Tb.N in group C, D, E were slightly elevated compared to group B, especially the group E (P < 0.05). Serum calcium and phosphorus values did not change significantly (P > 0.05). ALP values in group B was significantly higher than that in group A (P < 0.05).. Intermittent application of parathyroid hormone in small doses can increase alveolar BMD of castration rats and improve their bone structure. And it can have synergy effects on the treatment of osteoporosis if it is used combining with estrogen.

Topics: Alkaline Phosphatase; Animals; Bone Density; Estradiol; Estrogens; Female; Osteoporosis; Ovariectomy; Parathyroid Hormone; Rats; Rats, Sprague-Dawley; Rats, Wistar

To investigate the effect of estrogen on expression of matrix GLA protein (MGP) in ovariectomized Sprague-Dawley (SD) rats and the role of estrogen in improving postmenopausal osteoporosis.. Thirty-six SD female rats were allocated into 3 groups randomly, every 12 rats in ovariectomized group (OVX group), estrogen group (E group) and control group (sham group). Rats in OVX and E group all underwent bilateral ovariectomy, those rats in E group were given by estradiol benzoate intramuscularly after 3 weeks of ovariectomy. Rats in sham group underwent bilateral lipectomy near the ovary. All rats were kept the urine and the serum every three weeks and were sacrificed after 15 weeks. The pathology changes of uterus, lumbar vertebral bones were observed by immunohistochemistry. Bone mineral density (BMD) of lumbar vertebra of rats was determined by dual energy X ray absorptiometry (DEXA). The content of MGP in serum and urine was determined by ELISA. Expression of undercarboxylated matrix GLA Protein (MGP) was detected by immunohistochemistry. Relative quantification of MGP mRNA expression in lumbar vertebra bone was detected by Fluorescent real-time quantitative polymerase chain reaction.. (1) After 15 weeks of ovariectomized, the endometrium of uterus and lumbar vertebra exhibit remarkable pathologic changes in OVX group. The serum estrogen of (454 ± 66) pmol/L in OVX group were lower than in (527 ± 77) pmol/L in sham group and (556 ± 80) pmol/L in E group significantly (P < 0.05). The BMD of lumbar vertebra of (0.263 ± 0.030) g/cm(2) in OVX group were lower than (0.295 ± 0.024) g/cm(2) in sham group and (0.279 ± 0.024) g/cm(2) in E group significantly (P < 0.01). (2) The serum MPG protein in OVX group and E group showed decreased trends after ovariectomized, which were (104 ± 64) ng/L in OVX group and (134 ± 6) ng/L in E group at 9 weeks, which reached statistical difference (P < 0.05). However, MGP in urine in sham group did not exhibit significant difference after 15 weeks of surgery (P > 0.05). The MGP in urine of E group showed increased trends after 12 weeks of surgery, which reached (110.0 ± 3.4) ng/L at 15 weeks, in the mean time, it was found that (86.5 ± 2.5) ng/L of MGP in urine in OVX group, which showed significant difference (P < 0.05). (3) MGP could be observed in lumbar vertebra in OVX group by immunochemistry staining. In the other two groups, the expression of MGP was not dominant. (4) Relative quantification of MGP mRNA expression in lumbar vertebra was defined as 1 in OVX group, when compared with 0.289 ± 0.260 in E group and 0.103 ± 0.098 in sham group, the difference showed statistically significant (P < 0.01).. Estrogen could increase the expression of MGP mRNA and protein in ovariectomized rats and might play an important role in improving postmenopausal osteoporosis.

Topics: Animals; Bone Density; Calcium-Binding Proteins; Endometrium; Enzyme-Linked Immunosorbent Assay; Estradiol; Estrogens; Extracellular Matrix Proteins; Female; Immunohistochemistry; Lumbar Vertebrae; Matrix Gla Protein; Osteoporosis; Ovariectomy; Random Allocation; Rats; Rats, Sprague-Dawley; RNA, Messenger

Fracture healing in osteoporosis is delayed. Quality and speed of fracture healing in osteoporotic fractures are crucial with regard to the outcome of patients. The question arises whether established antiosteoporotic drugs can further improve fracture healing.. Osteoporosis manifests predominantly in the metaphyseal bone. Nevertheless, an established metaphyseal fracture model is lacking. A standardized metaphyseal fracture-healing model with stable plate fixation was developed for rat tibiae. The healing process was analyzed by biomechanical, gene expression, and histomorphometric methods in ovariectomized (OVX) and sham-operated rats (SHAM), compared to standardized estrogen (E)- and raloxifene (R)-supplemented diets.. Estrogen and raloxifene improved the biomechanical properties of bone healing compared to OVX (Yield load: SHAM = 63.1 +/- 20.8N, E = 60.8 +/- 17.9N, R = 44.7+/-17.5N, OVX = 32:5 +/- 22.0N). Estrogen vs OVX was significant based on a denser trabecular network. Raloxifene greatly induced total callus formation ((R = 5.3 +/- 0.9 mm2, E = 4.7 +/- 0.5 mm2, SHAM = 4.51 +/- 0.61 mm2, OVX =4.1 +/- 0.6 mm2), whereas estrogen mainly enhanced new endosteal bone formation. There was no correlation between the gene expression (osteocalcin, collagen1alpha1, IGF-1, tartrate-resistant phosphatase) in the callus and the morphology and quality of callus formation.. Raloxifene and estrogen improve fracture healing in osteoporotic bone significantly with regard to callus formation, resistance, and elasticity. The biomechanically stable metaphyseal osteotomy model with T-plate fixation presented here has proven to be appropriate to investigate fracture healing in osteoporosis.

Topics: Analysis of Variance; Animals; Biomechanical Phenomena; Bone Density Conservation Agents; Disease Models, Animal; Drug Therapy, Combination; Estradiol; Female; Fluorescent Dyes; Fracture Fixation, Internal; Fracture Healing; Microradiography; Osteoporosis; Osteotomy; Ovariectomy; Raloxifene Hydrochloride; Rats; Rats, Sprague-Dawley; Tibial Fractures

This study is an experimental study in the rat osteopenia model.. The aim of this study was to evaluate the short-term effects of daily application of parathyroid hormone (PTH) on bone quality and quantity using a new biomechanical compression test for intact rat lumbar vertebrae.. Because of their high clinical relevance, trabecular content and thick cortical shell vertebrae are of high interest for osteoporosis research. Biomechanical stability depends on both trabecular and cortical bone. Anabolic effects on bone after long-term application of PTH have already been proven.. After an intraindividual comparison (n = 20), the capability of a new test to identify biomechanical properties of the mature rat model was assessed. In the following, 33 three-month-old rats were ovariectomized. After 10 weeks, the animals were divided into 3 groups. The control group (C) received no additional food supplementation. The other groups received hormone treatment with either estradiol (E) or PTH for another 5 weeks. The effects on bone biomechanical properties and bone microstructure were analyzed.. After establishing the new biomechanical test for intact rat lumbar vertebrae, PTH-treated (yield stress: 2.95 N/mm, elastic limit: 2.39 N/mm) and then E-treated (yield stress: 2.13 N/mm, elastic limit: 1.68 N/mm) animals showed superior biomechanical results. Compression strength was significantly improved in these rats in comparison to the control group rats (yield stress: 1.86 N/mm, elastic limit: 1.38 N/mm). In the microradiographic evaluation, PTH significantly improved the morphologic results to produce thicker trabeculae. E led to a more densely branched trabecular network, which was not as important as trabecular thickness for bone stability.. After a short-term application, PTH is superior to E in recreating bone biomechanical propertiesand lumbar vertebral microstructure in advanced osteoporosis. The cortical shell and trabecular thickness are primarily responsible for the biomechanical strength of vertebrae.

Topics: Administration, Oral; Animals; Biomarkers; Biomechanical Phenomena; Bone Density Conservation Agents; Bone Remodeling; Compressive Strength; Disease Models, Animal; Estradiol; Estrogen Replacement Therapy; Female; Injections, Subcutaneous; Lumbar Vertebrae; Microradiography; Osteocalcin; Osteoporosis; Ovariectomy; Parathyroid Hormone; Rats; Rats, Sprague-Dawley; Time Factors

Oestrogen deficiency leads to a considerable bone loss, thus, osteopenia and osteoporosis are serious complications after menopause.. To evaluate the effects of a daidzein metabolite equol on bone mass density (BMD) and markers of bone remodelling in an ovariectomized (ovx) rat model of postmenopausal bone loss and compare them with the effects of 17beta-estradiol.. Twenty-eight female Sprague-Dawley rats were ovx and fed soy-free chow only (control group, n = 8), or with the addition of oestradiol-3 benzoate (E2B) (10mg/kg, n = 10) or equol (400 mg/kg, n = 10). At baseline and after 6-week treatment period, proximal tibia and lumbar spine BMD were measured using computer tomography. Animals were then sacrificed, blood was collected and uteri were removed.. Similarly to E2B, dietary equol decreased weight gain and showed mild uterotropic activity. E2B attenuated ovx induced BMD loss at proximal tibia whereas equol had no effect. At lumbar spine, however, equol not only attenuated trabecular bone loss but also increased its density. This effect was also apparent in animals treated with E2B. Cortical BMD at proximal tibia and lumbar spine were not very much influenced by ovx and treatment with E2B or equol did not induce significant changes at these sites. Plasma osteocalcin and type I collagen fragments (cross-laps) in equol treated animals did not differ from the controls whereas in E2B treated animals they were both significantly decreased.. In spite of its mild uterotropic potential, dietary equol shows limited bone sparing effects in ovx rats.

Topics: Animals; Bone Density; Dietary Supplements; Equol; Estradiol; Female; Isoflavones; Osteoporosis; Ovariectomy; Phytoestrogens; Phytotherapy; Rats; Rats, Sprague-Dawley

Topics: Animals; Estradiol; Mice; Muscular Dystrophies; Osteoporosis; Testosterone; Testosterone Propionate