The Preventive Effect Of Aspirin On Osteoporosis In Ovariectomized Rat

Osteoporosis is the most common metabolic skeletal disorder, characterizedby a reduction in bone mass and microarchitectural deterioration of bone tissue,resulting in skeletal fragility and susceptibility to fractures. Osteoporosis hasbecome a hidden killer to human health and has been recognized as a majorhealthcare problem which will affect the global economy and individualpshchology. In addition, with the population aging, the incidence of osteoporosisis predicted to increase, especially in China and other developing countries.Therefore, the prevention and treatment of osteoporosis is an important task forhuman beings.The earlier research of our group show that osteoporosis model can besuccessfully established by ovariectomized of the rat after three months, andaspirin treatment can effectively increase the ovariectomized rat bone density,promote the trabecular bone remodeling and improve three-dimensionalstructure of trabecular bone. However, the prevention effect and its mechanism of aspirin on osteoporosis, the optimal dose of aspirin, and the side-effect ofaspirin gastric mucosa remains unclear. Based on these questions, the followingstudies were esteblished:(1)Totally48three-month-old female SD rats wererandomly divided into6groups with8rats in each group: OVX group，Shamgroup and Aspirin groups(A1、A2、A3、A4),The rats in OVX group and Aspiringroups were ovariectomized to establish osteoporosis model, After one week,aspirin was intragastrically administered at a dose of2.25mg/kg.d (A1)、4.46mg/kg.d (A2)、8.926mg/kg.d (A3)and26.75mg/kg.d(A4) for all the rats inaspirin groups, OVX group and Sham group rats were given the same amount ofsaline.(2) The bone source alkaline phosphatase and osteocalcin weredetermined by Enzyme--Linked ImmunoSorbent Assay (ELISA);(3) The BMDwas measured with the dual-energy X-ray absorptiometry to measure the fifthlunbar vertebral body bone mineral density;(4) The trabecular architecturechanges and the stress reaction of Stomach mucosal were observed byhistomorphology;(5) The three-dimensional morphology of lumbar vertebraltrabecular were evaluated with the micro-CT machine.The results revealed that:（1）The bone source alkaline phosphatase decreased significantly inaspirin treated A3and A4group, compared with those in the OVX group（p<0.05）,and the bone gamma-carboxyglutamic-acid-containing proteinsincreased significantly in A2、A3and A4group, compared with those in thesham group（p<0.05）.（2）The morphology of trabecular bone in aspirin groups was better thanthat in the OVX group, In the A3and A4group, the erythema and submucosalhemorrhage could be noticed in the gastric mucosa, While, more obvious in A4group. （3）The DXA show that the BMD in Aspirin groups was significantlyhigher than that in the OVX group（P<0.01）.（4）Compared with the OVX group, the BV/TV、Tb.Th、Tb.N、BMDwere significantly increased in the aspirin groups（P<0.01）, while the BS/BV、Tb.Sp were significantly decreased（P<0.01）. The BV/TV、BS/BV、Tb.Th、Tb.N、Tb.Sp、BMD in the aspirin groups were significantly different comparedwith that in the Sham group (P <0.01)．Conclusion: Aspirin can improve trabecular bone structure, increase bonemineral density，prevent the occurrence of postmenopausal osteoporosis, Themechanism of this effect is probably by the inhibiting of bone resorption andstimulating of bone formation function of the aspirin. It is relatively safe forpreventing of osteoporosis with low-dose aspirin．...