| Objective: Postmenopausal osteoporosis is a common disease in postmenopausal female, characterized by low bone mass , microarchitectural deterioration of bone tissue leading to enhanced bone fragility and an increase in fracture risk. The disease is a kind of primary osteoporosis with high turnover rate which is caused by compound factors, such as hormone, age, disuse, heredity, immune, nutrien et al.The recent study show that advanced glycosylation end products (AGEs) play a important role in osteoporosis pathogenesis, which were formed spontaneously in proteins by a non-enzymatic reaction with sugar, characterized with specific fluorescence and cross-linked structures. It is necessary for normal tissue remodeling and homeostasis. But excessive formation and accumulation of AGEs will induce a series of pathologic changes. On the one hand, by their biochemical properties, AGEs induced direct pathogenic lessons. On the other hand, by the combination of AGEs with their receptors on surface of cell membrane, AGEs stimulated these cells to synthesis and release a series of cytokines and growth factors affecting the proliferation anddifferentiation of target cells in tissues and the synthesis and release of the extracellar matrix, which lead to indirect pathogenic alternation. AGE-formation on collagen resulted in increasing collagen insolubility and cross-linking, which altered the microarchitecture and functional properties of the collagen. In addition, AGEs can stimulate monocyte and osteoblast to produce some cytokines associated with bone absorption, such as IL-1, IL-6, TNF and so on. It's reported that AGEs play a important role in senile and diabetic osteoporosis. Ageing and carbohydrate metabolism disorder are important cause of accumulation of AGEs, while menopause can result in carbohydrate metabolism disorder.Osteocalcin is a bone-specific extracellular matrix protein produced by mature osteoblast in Mineralizing bones, it is associated with extracellular matrix maneralization and is a index reflecting bone formation and turnover rate. In this study, we have investigated the effect on postmenopausal osteoporosis of AGEs by observing influence of AGEs on osteocalcin synthesis in ovariectomized rat and rat calvaria-derived osteoblast. Method:1. Animal model: thirty-nine Sprague-Dawley rats (ten months of age) were divided randomly into three groups: Sham group (Sham), Ovariectomized group(OVX), Ovariectomized +aminoguadinine group (OVX+AG)2. Measurement of AGE content of bone collagen bydetermination of collagen-linked fluorescence.3. Measurement of serum OC concentration by RIA.4. Measurement of bone OCmRNA by RT-PCR.5. Measurement of BMD with double X-ray bone mineral density machine.6. Measurement of some biochemical marker.7. Influence on AKP activity and OC synthesis of AGEs in vitro: Measurement of AKP activity in cells and OC concentration in DMEM after rat calvaria-derived osteoblastic cells incubated for different period of time with different doses of AGE-BSA prepaired in vitro.Result:1. AGE contents of bone collagen: Contents of AGE of bone collagen in OVX group increased compared with that in sham group (P<0. 01); Contents of AGE of bone collagen in OVX+AG group reduced compared with that in OVX group (p<0. 05).2. Femur and tibia BMD: Femur and tibia BMD in OVX group were remarkably lower than that in sham group (P<0. 05); Femur BMD in OVX+AG group had an increase tendency compared with that in OVX group; Tibia BMD in OVX+AG group were remarkably higher than that in OVX group.(p<0. 05).3. Bone OCmRNA expression: Expression of bone OCmRNA in OVX group were remarkably higher than that in sham group (P<0. 05); Expression of bone OCmRNA inOVX+AG group were remarkably lower than that in OVX group (p<0. 05).4. Concentration of serum OC: Contents of serum OC in OVX group had an increase tendency compared with that in Sham group; Contents of serum OC in OVX+AG group had a decrease tendency compared with that in OVX group.5. Bioch...
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