| Background:Osteoporosis has been recognized as a bone metabolic disease which is characterized by the continuous loss of bone mass and subsequent degeneration of bone microarchitecture. The prevalence of osteoporosis is relatively high in both developed and developing countries.Approximately 200 millions people worldwide are suffering from osteoporosis.The latest statistics showed that the number of osteoporosis patients in China has reached 90 million, and the incidence is greater than that of 20% in women older than 50 years. Healthy bone microscopically appears like a honeycomb but, in osteoporotic patients the spaces are much bigger. The osteoporotic bone will have less bone density or bone mass and the structure of bone tissue is abnormal. As the bone becomes less dense, they become weaker and more likely to be fractured. Oral health maintenance for adults with osteoporosis is important. Bone weakness and loss may also affect the retention and stability of the dentures. For alveolar bone osteoporosis patient, bone density decreasing and biological mechanics performance reducing lead to accelerate bone resorption, and the alveolar bone height and width will be decreasing, Itwill cause inconvenience for implant, removable partial denture and complete denture restoration in the end.Currently, the preventive and therapeutic strategies for osteoporosis patients are based on the supplementation of calcium and vitamin D, use of pharmacological agents also could inhibit bone resorption such as bisphosphonates, and occasionally in need of the administration of calcitonin.However, there are some problems such as expensive treatment cost,long time treatment and more side effects. Long-term use of hormone replacement therapy is prone to increase the risk of breast cancer, stroke,and cerebral infarction. Bisphosphonate therapy may lead to severe suppression of bone turnover and even osteonecrosis of the mandible.Therefore, it is of great clinical significance to find out a novel treatment strategies for osteoporosis.The key pathophysiological mechanism of osteoporosis is the imbalance between the bone resorption and the bone formation. In addition to targeting the inhibition of bone resorption, stimulation and restoration of bone formation is also considered to be an effective way for osteoporosis. Bone formation is mainly mediated by the osteoid-secreting osteoblasts. However, this physiological repair process is tempered in the elderly due to the limited regenerative ability and the decreased numbers of the osteoblast progenitor cells, termed bone marrow mesenchymalstem cells(BMSCs).Currently, The rapid development of regenerative medicine and technology for stem cell transplantation is bringing new hope to patients with osteoporosis. BMSCs initially derived from bone marrow stromal cells and have the ability to self renew. Rodan et al. demonstrated that BMSCs have multiple differentiation potentials. Different transcription factors can regulate BMSC differentiation into osteoblasts and adipocytes.Both of these types of cells play an important role in the maintenance of normal bone stability states. Therefore, BMSCs could offer a potential source of cell and gene therapy.Plants have provided a rich source of therapeutic agents and bases for synthetic drugs.Ginkgo biloba extract(GBE), a traditional Chinese natural herb, has attracted immense attention for its treatment of diverse diseases, including coronary heart disease, Alzheimer disease and multi-infarct dementia, cerebral insufficiency, and renal ischemia-reperfusion injury. Our research group found that GBE could promote the osteogenic differentiation of rat BMSCs and inhibit the adipogenic differentiation at the same time. However, little is known about the osteogenic effect of GBE on BMSCs.Objective:To reveal the mechanism of how GBE promotes osteogenic differentiation of rat BMSCsMethods:1. The separation and culture of rat BMSCsWe separated the BMSCs of 1-week-old Wistar rat by whole marrow method and passaged to pure the cell. Through the identification test to make sure that the cells we separated were the BMSCs of multiple differentiation potential. We considered that the third generation BMSCs will be better for the experiment.2. Test the effect of GBE on the proliferation of BMSCsApplying the 150mg/L GBE on the third-generation of BMSCs,and the inhibitor group underwent a pretreatment of SB203580,which is the specific inhibitor of P38 MAPK signaling pathway. The results were elaluated by Alkalinet phosphatase method at day 7, Alizarin Red S at day12. Real-Time PCR was taken to test the expression of the osteogenesis related genes(BMP-2, Runx2, ALP, OCN) m RNA at 1 week.Results:1. Alkaline phosphatase(ALP) is a cell marker of osteoblasts and its activity is often used to indicate osteogenesis at the early stage. The results showed that the ALP antivity inhibitor group is significantly lower than control group.2. We used ARS staining at day 12 to measure the effect of GBE on osteogenesis at the late stage. The results showed that the calcium depositions are fewer than that in control group.3.The osteogenic related genes(BMP-2,Runx2,ALP,OCN)m RNA expression of inhibitor group were also relatively lower than that in control group and the results had significant differences.Conclusion:Ginkgo biloba extract promotes osteogenic differentiation of rat BMSCs by upregulating the P38 MAPK signaling pathway. |
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