OBJECTIVETo investigate the effects of Chinese kidney-tonifying drugs on bone mineral density, biomechanics, 25-hydroxy Vitamin D3 and 1,25-dihydroxy Vitamin D3 of ovariectomized osteoporosis rats, and explore the mechanism of treating osteoporosis with the drugs.

METHODSThirty-six female SD rats (four months) were randomly divided into model group, sham group and treatment group. All the rats had been ovariectomied except those in sham group. Selecting 4, 8, 12 weeks in the experiment, the value of bone mineral density (BMD) was measure by dual energy X-ray absorptiometry (DEXA) of femoral head, while the biomechanics machine was applied to analysis femoral head biomechanics index and ELISA method was used to detect the content of 25-hydroxy Vitamin D3 and 1,25-dihydroxy Vitamin D3 discern in blood-serum, liver and kidney.

RESULTSTreatment group rats' BMD of femoral head was enhance compared with model group, significant differences were absent (P<0.05), and the maximal load and maximal stress measurement were improved, significant differences were absent (P<0.05). As the content of 25-hydroxy Vitamin D3 and 1,25-dihydroxy Vitamin D3 discern in blood-serum, liver and kidney were elevate, furthmore there were significant differences in group comparison, all significant differences were absent (P<0.05). But those compared with sham group, there was no significant difference (P>0.05).

CONCLUSIONIn the early period in absence of estrogenic hormone, the Chinese kidney-tonifying drugs could activate bone metabolism to raise BMD and reinforce quality of bone through up-regulating expression of 25-hydroxy Vitamin D3 and 1,25-dihydroxy Vitamin D3 at protein level.