| Osteoporosis(OP)is a chronic disease characterized by degenerative diseases of the whole body.During the progression of the disease,the bone mass and bone mass decrease,resulting in the destruction of the fine structure of the bone and the weakening of the structural material.It is prone to fractures.Due to the close relationship between estrogen and bone metabolism,the incidence of osteoporosis in postmenopausal women older than 50 years of age is quite high.The neccesity and critical needs of studying its pathogenesis,clinical prevention and development of drug to treat osteoporosis in scientific research and clinical practice is a relevant osteoporosis animal model.In animal models of osteoporosis,bone morphology and bone metabolism in non-human primates are highly similar to humans;the animal model of non-human primate is an essential part in the research and development of new drugs,which further highlights the urgency of research on the appropriateness and effectiveness of this animal model in developing clinical therapeutics.The evidence for the safety and effectiveness of alendronate in the treatment of osteoporosis is ampler than any other drug.Long-term data with parallel controls and combination tests in current experiment should make it a good candidate for use as a positive control in the efficacy studies of osteoporosis animal models.In this study,Alendronate(ALN)was used as a positive control drug,and the animal model was validated by evaluating its therapeutic effect.In this study,12 female cynomolgus monkeys were randomly divided into three groups according to body weight and bone density(4 in each group): OVX + vehicle group(physiological saline;10 mL/animal/week;oral),OVX + Alendronate(ALN)group(5 mg/animal/week;oral),sham + vehicle(saline;10 mL/animal/week;oral);animal model.One month after ovariectomy surgery,the subjecs received continuous treatments(as specified above,respectively)for 11 months.During the entire study period,X-ray imaging,bone metabolism-related hormone levels,bone turnover biochemical markers,bone mineral density by DXA and pQCT were done.After the in-life period,Micro-CT,bone histomorphometry,and biomechanics were performed on collected specimens from all animals,and statistical analysis was performed on the data.Bone metabolism-related hormone levels showed that the levels of estrogen in the OVX + Vehicle group and the OVX + ALN group were significantly lower than those before surgery and that of the level in the Sham + Vehicle group,at one-month time after the ovariectomy surgery and before dosing.Serum threshold of 110.140 pmol/L(30 pg/mL)is an important indicator to judge the success of ovariectomy in macaque monkeys [50].Parathyroid hormone(PTH)levels and 1,25-dihydroxyvitamin D levels in the OVX surgery group decreased significantly at one-month post-ovariectomy and remained at the same level at1-month and 6 months and before the termination.The overall trend of the three hormone levels in the Sham + Vehicle treatment group was stable.In the OVX + Vehicle group,hormonal reduction was clearly induced by ovariectomy,and bone formation-associated bone turnover markers sALP(bone specific alkaline phosphatase)was significantly elevated,and bone resorption-related bone turnover markers CTx-I(type I collagen carboxy terminal peptide)was also significantly increased.Alendronate was able to reduce bone formation-associated bone turnover markers sALP and bone resorption-related bone turnover markers CTx-I in these estrogen-deficient female monkeys.In addition,there was a statistically significant difference between the OVX + ALN group and the OVX + Vehicle group on these markers to demonstrate the treatment effects.Data from the DXA and pQCT scans showed that the OVX + Vehicle group had a significant reduction in BMD(Bone Mineral Density)due to reduced hormones induced by ovariectomy.Alendronate sodium was able to revert this decreased BMD(Bone Density),since the OVX + Vehicle group had statistically significant lower BMD as compared to the OVX + ALN group and the Sham + Vehicle treatment group.Micro-CT examination of lumbar trabecular bone structural parameters and bone histomorphometric analysis showed that alendronate sodium was able to increase in parameters such as BV/TV,Tb.Th and Tb.N,reduce Tb.Sp and the elevated bone resorption-related bone histomorphometric parameters,such as Oc.S/BS,resulted from estrogen-deficiency in these ovariectomized monkeys.Alendronate was able to reduce the bone formation-related bone histomorphometric dynamic parameters such as MAR,OS/BS,BFR/BV,in these ovariectomized monkeys.Also,the differences on these markers between OVX + Vehicle group and Sham + Vehicle group were statistically significant.Bone biomechanical tests showed that there was a statistically significant difference between the groups.The OVX + Vehicle group was statistically significant different from the Sham + Vehicle treatment group.Alendronate sodium was able to increase cancellous bone strength parameters(Maximal Load,Ultimate load to failure,Stiffness),since OVX + ALN group were greater than OVX + Vehicle group and Sham + Vehicle treatment.Overall,the cortical bone biomechanical test results of OVX + Vehicle group and OVX + ALN were basically consistent with cancellous bone results,but the rate of change was apparently less than that of cancellous bone.This indicating that Alendronate was less effective in regulating various parameters of cortical bone than cancellous bone.Taken together,the data showed that the OVX + Vehicle group displaying a significant negative-balanced high bone turnover,which is consistent with the pathogenesis of postmenopausal osteoporosis.All test results showed that alendronate had significant therapeutic effects on osteoporosis caused by estrogen-deficiency after ovariectomy,especially for sites with high cancellous bone content such as lumbar spine.The normal range of the test results in the Sham + Vehicle group fluctuates,which reflected seasonal cycles of bone physiology.Judging from these information,the objective of this study was achived and establishment the animal model of ovariectomized(OVX)-induced osteoporosis in female cynomolgus monkey was confirmed;and the success of the modeling by verifying the efficacy of alendronate treatment was revealed.The obtained data and experimental methods and experience can provide a reliable animal model for the research and development of related osteoporosis drugs and their therapeutic mechanism. |
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