[Comparative study of effects of hormonal therapies on the healing of fracture in ovariectomized rats and Rats' endometria].

OBJECTIVE

To compare the effects of Livial, Progynova and Premarin on osteoporosis associated with femoral fracture in rats, and assess these drugs' influnces on the rats' endometria in order to provide a therapeutic regiment appropriate for postmenopausal osteoporotic fracture.

METHODS

Ninety 6-month-old SD female rats were randomly divided into five groups:SHAM, OVX, Livial, Progynova and Premarin. The osteoporotic model was established by ovariectomy except for Sham group. The right femur was broken by operation 8 weeks later. Livial, Progynova,Premarin tablets were given after operation respectively. The rats in five groups were killed at the end of 2, 4, 6, 8 weeks after operation respectively. The study indices included the histological appearance and histomorphometry of bone calluses, osteoblasts, osteoclasts, and endometrium.

RESULTS

There were more osteoclasts in OVX group than in other four groups,but no statistically significant differences in number of osteoblasts on the surface of osseous trabecula were seen among the five groups. The biggest area of trabecula was in Livial group while the smallest area was in Progynova group, especially at 4 weeks after operation. The hyperplasia of endometrium measured by morphometry was the same in the Progynova,Premarin groups as in Sham group, whereas it was not found in Livial group at 8 weeks postfracture.

CONCLUSION

Estrogen is good for healing of postmenopausal osteoporotic fracture. The possible mechanism relevant to healing is that estrogen inhibits bone absorption, stimulates bone formation, reduces bone turnover and accelerates bone-remodeling. When compared against the treatment with estrogen alone, the treatment with combined sex hormones has better effects on fracture healing. Livial would not bring about endometrium hyperplasia.