Influence of alfacalcidol on the levels of bone quality,vitamin D metabolites and renal expression of vitamin D receptor(VDR) mRNA in ovariectomized rats

Objective To investigate the influence of alfacalcidol on the levels of two bone metabolism makers, 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D_3,and renal expression of VDR mRNA in ovariectomized rats,and to explore the metabolism conditions of vitamin D endocrine system in ovariectomized rats,then to find out a cost-effective method to prevent and treat of postmenopausal osteoporosis.Methods 36 female SD rats(eight months) were randomly divided into model group,sham group and treatment group.All rats were killed three months later,and then dual energy X-ray absorptiometry(DXA) and biomechanics test were used to evaluate BMD and bone quality of the model.ELISA method was used to detect the content of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D_3 in serum or tissue.While, fluorescence quantitative PCR(FQ-PCR) method was used to quantitative analysis of expression of renal VDR mRNA. Results The BMD,index of maximal load and maximal stress of femoral head or trochanter were decreased significantly in model rats(P0.05),while,the content of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D_3 discern in serum, liver and kidney were higher in treatment group(P0.05).But compared with sham group,there was no significant difference.The expression of VDR mRNA had a statistical significance between treatment group and model group(P = 0.004).Conclusion This study shows that appropriate amount of alfacalcidol can effectively prevent and treatment of bone loss and bone qulity decrease in ovarectomized rats and provide the evidence for treatment of postmenopausal osteoporosis.