[Effects of estradoil valerate on osteoporosis in ovariectomized rats]

Compared with 17beta-estradiol, to evaluate the effects of estradiol valerate on osteopenia in ovariectomized rats.

Forty two six months old female Wistar rats were randomly divided into 5 groups performed ovariectomy (OVX) or sham-operation. (1) 6 weeks after OVX (Ovxb, n = 8): sacrificed at 6 weeks after OVX; (2) Sham ovariectomized (n = 8); (3) 14 weeks after OVX (Ovxe, n = 8); (4) 17beta-estradoil treated group (O + E, n = 9, with 17beta-estradiol 20 microg x kg(-1) x d(-1) Sc.); (5) Estradoil valerate treated group (O + EV, n = 9, with estradiol valerate 800 microg x kg(-1) x d(-1) po). Treatment started 6 weeks after OVX and lasted for 8 weeks. Histomorphometry analysis of tibia, peripheral quantitative computed tomography (pQCT) scanning of femur, bone biomechanical test in femur were performed.

OVX induced osteopenia and increase of bone turnover. Compared with Ovxe, O + E and O + EV caused an evident reduction of urinary deoxypyridinoline/creatinine, a bone resorption marker, by 54.6% and 77.4% respectively (all P < 0.01). Both O + E and O + EV lowered the high level of eroded surface, mineral surface and bone formation rate induced by OVX. An increase of 122.3% and 119.7% in trabecular bone volume respectively in O + E and O + EV group, compared with Ovxe group. Microarchitecture of trabeculea also improved in those two groups. The trabeculae bone mineral density determined by pQCT were significantly increased in O + E and O + EV compared with Ovxe group (99.5% and 128.4% P < 0.01). Similarly, significant increases were found in cancellouse maximal load and canceallous stiffness of distal femur in O + E, but not O + EV. There was no significant difference in these changes between the group O + E and O + EV.

Oral estradiol valerate performed effects similar to those of 17beta-estradiol Sc. in inhibiting bone turnover, protecting bone loss and increasing bone mineral density of trabecular bone.