[Effects of combined treatment with flouride and 1,25-dihydroxyvitamin D3 on the histomorphometry and biomechanical properties of bone in ovariectomized rats].

OBJECTIVE

To evaluate the potential use of a combination of bone formation-promoting agents and a differentiation agent of osteoblast as a treatment for postmenopausal osteoporosis.

METHODS

The effects of combined and separate administration of flouride-Ca (0.45 ng F- + 13.56 mg Ca2+)/(kg.d) and 1,25-dihydroxyvitamin D (135 pmol/d s.c.) on the histomorphometric parameters in the secondary spongiosa of proximal tibia and biomechanical properties of femoral midshaft in ovariectomized (OVX) rats were examined.

RESULTS

Compared with OVX group, OVX + fluoride-Ca group (O + F) and OVX + Fluoride-Ca + 1,25-dihydroxyvitamin D(O + F + D) two kinds of treatment caused 42%, 91% more in %Tb Ar, 14%, 38% more in Tb Wi, 24%, 46% more in Tb N, 26%, 43% less in Tb Sp, 45%, 42% less in % E Pm, 30%, 60% more in Ob Pm respectively. W Wi in O + F treatment had no significant difference from OVX group but 15.2% in O + F + D treatment compared with sham group, MLT increased 16% in O + F group, had no difference from O + F + D. No significant alteration of mechanical strength at femoral midshaft in both O + F and O + F + D was found. There were significant difference in above changes of parameters except % Ob Pm.

CONCLUSIONS

Above two treatments could prevent the loss of cancellous bone, reduced the resorption caused by OVX, protected trabecular microarchitecture, and stimulated bone formation significantly. The combined treatment avoided potential mineralization defect caused by F-Ca treatment alone, and two treatments maintained mechanical strength at femoral midshaft.