| Objective To research the effects and possibility mechanisms of Premarin on osteoporosis association with femoral fracture in ovariectomized rats , and to provide the possibility of treatment for postmenopausal osteoporotic fracture.Method 54 Sprague-Dawley(SD) female rats , aged 6-month-old, were divided into 3 groups randomly: the SHAM group, the OVX group and the Premarin group. The osteoporotic model was established by ovariectomy except the SHAM group. The right femur was broken by operation at 8th week. Premarin tablets were immediately given through gastromy,0.0625mg/ kg/d, after operation in the Premarin group. Rats in 3 groups were killed at the end of 2~nd ,4~th, 6~th , 8~th weeks postoperatively respectively for research .Research index include: the bone of X-rays; the histological of bone calluses(HE dye and Masson dye), the index of osteoblast and osteoclast, immunohistochemistry and the integrated optical density (IOD) of bonecollagen I ; the oculus dehter of cartilage and callus of break of right femur; the biomechanical properties of right femur.Results 1. The density of calluse was decreased obviously in OVX group. The line of fracture was still exist in OVX group while it was dimness or disappeared in the SHAM and in the Premarin group. 2. In the OVX group, there was a little more cartilage during the early callus formation stage. There was more number of osteoclasts in the OVX group than in other two groups and there was no obvious difference of number of osteoblasts in the 3 groups on the surface of osseous trabecula. Original trabecular bones were changed slowly into mature trabecular bone and part of them had been absorbed and disappeared at 8th week in OVX group. In other two groups trabecules became thicker and denser gradually. Osteoblast index was the same level in three groups in every week. Osteoblast index of the Premarin group was lower than that of the OVX group in 2nd , 4th week, but were with the same level of the SHAM group. The area of bone trabecula of the Premarin group was h igher t han t hat o f the O VX group i n 6th , 8th w eek, b ut w as with the same level of the SHAM group. The area of bone trabecula was no different in the OVX group in every week, but the area of bone trabecula of the Premarin group and the SHAM group in 8th week was higher than that of in 2n week. 3. The oculus dehter of cartilage and callus of break in the Premarin group were lower than that of OVX group at 8th week, but were with the same level of the SHAM group. 4.The consequence of elastic modulus > elastic deformation > destructive intension of right femur in the Premarin group were better than that of in the OVX group. 5.The collagenous fibers were arranged looser and more irregular in the OVX group than in theSHAM and the Premarin group. The type I collagen mostly was expressed in cartilage and matrix around cartilage. Subsequently it was expressed in osteoblast, matrix around osteoblast, osseous trabecula, calluses and tissues around callus. The IOD of type I collagen was highest at 4th week in every group. But the IOD of type I collagen in the Premarin group and the SHAM group were the same level and higher than that in the OVX group.Conclusion (1): Premarin is good for fracture h ealing of postmenopausal osteoporosis, especially early fracture healing.(2): The mechanism is possibaly that Premarin may increase the activity of osteoblast, reduce the number of osteoclast and depress the activity of osteoclast, restrain the high bone tuneover after ovariectomy, increase the content of type I collagen and make the collagen shape closer and uniform, make the biomechanics properties better, and favor the healing of the osteoporosis fracture. |
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