Piperazinyl estrone prevents bone loss in ovariectomized rats / 药学学报

<p><b>AIM</b>To determine the effect of piperazinyl estrone, a new estrogen derivative, on bone turnover, bone mass and uteri in ovariectomized rats.</p><p><b>METHODS</b>Female Sprague-Dawley rats were ovariectomized (OVX) or sham operated (sham) at the age of 3 months and treated with estrone (E) at 0.75 mg.kg-1.d-1, or with piperazinyl estrone (P-E) at 1 or 10 mg.kg-1.d-1, orally, for 3 months. At the time of death, the uterine weight was measured. Bone histomorphometric analysis of proximal tibial metaphyses (PTM) was performed in undecalcified sections.</p><p><b>RESULTS</b>Bone histomorphometric data showed that the percent trabecular area (% Tb.Ar) of OVX rats with bone high turnover was significantly decreased. The uteri were atrophied. The percent trabecular area (% Tb.Ar) of estrone treated group was increased in decreasing bone turnover manner. But the size and weight of uteri in this group were increased vs OVX group. The bone loss induced by OVX was preserved by P-E treatment, but the mechanism of maintaining bone is different from that of E-treated rats. P-E treatment in low dose did not decrease any bone formation indices, such as percent labeling perimeter, bone formation rate per bone volume (BFR/BV), except bone mineral apposition rate (MAR) compared with E-treated group, and maintained them at OVX level. The uteri were found to be in atrophy compared with the match dose (0.75 mg) of E-treated OVX rats. But rats treated with high dose of P-E showed the same change like E-treated group.</p><p><b>CONCLUSION</b>The finding of this study shows that lower dosage of piperazinyl estrone has effect on preventing the bone losses in OVX rats, while the bone formation and the uterus are not affected, thus supporting the hypothesis that piperazinyl estrone has the potential to prevent postmenopausal bone loss in women with less side effects.</p>

C-mycprotein expression upregulated by 2-(3-estrone-N-ethyl piperazine-methyl) tetracycline in bone / 药学学报

<p><b>AIM</b>To study the effect of XW630 on expression of pro-oncogene c-myc in the long bones of fetal mice in vitro for postulating the mechanism by which XW630 exerts its effect on bone.</p><p><b>METHODS</b>The fetuses of pregnant mice were removed on day 16 of gestation, the long bones of the forelimbs of female fetal mice were freed of muscle and soft tissue and cultured in a specific device for 48 h in BGJb medium treated with 1 x 10(-7), 1 x 10(-8) and 1 x 10(-9) mol.L-1 XW630 in the final medium. After cultured for 48 h, the long bones were harvested and immunohistochemical analysis was performed for determination of c-Myc protein expression in epiphyseal plates. The areas of positive cells in the resting zone, proliferative zone and hypertrophic zone in epiphyseal plate were determined under image analytic system.</p><p><b>RESULTS</b>When the concentration of XW630 in the medium was 1 x 10(-9) mol.L-1, the area of c-Myc positive cells increased in the proliferative zone compared with 1 x 10(-9) mol.L-1 in the estrone group, significant increase was also observed in the resting zone compared with the control group. When the concentration of XW630 in medium was 1 x 10(-8) or 1 x 10(-7) mol.L-1, stronger expression than that in the control group and the estrone group at the same concentration was observed in each of the three zones.</p><p><b>CONCLUSION</b>The estrogenic effect of XW630 on bone was stronger than that of estrone. XW630 may promote proliferation and differentiation of chondroncytes by promoting c-Myc protein expression in chondroncytes. Thus, endochondral bone formation was enhanced.</p>