RESUMEN
Bone's microporosities play important biologic and mechanical roles. Here, we quantified 3D changes in cortical osteocyte-lacunae and other small porosities induced by estrogen withdrawal and two different osteoporosis treatments. Unlike 2D measurements, these data collected via synchrotron radiation-based µCT describe the size and 3D spatial distribution of a large number of porous structures. Six-month old female Sprague-Dawley rats were separated into four groups of age-matched controls, untreated OVX, OVX treated with PTH, and OVX treated with Alendronate (ALN). Intracortical microporosity of the medial quadrant of the femoral diaphysis was quantified at endosteal, intracortical, and periosteal regions of the samples, allowing the quantification of osteocyte lacunae that were formed primarily before versus after the start of treatment. Across the overall thickness of the medial cortex, lacunar volume fraction (Lc.V/TV) was significantly lower in ALN treated rats compared to PTH. In the endosteal region, average osteocyte lacunar volume (
Asunto(s)
Alendronato/farmacología , Conservadores de la Densidad Ósea/farmacología , Densidad Ósea/efectos de los fármacos , Huesos/efectos de los fármacos , Osteoporosis/tratamiento farmacológico , Alendronato/uso terapéutico , Animales , Conservadores de la Densidad Ósea/uso terapéutico , Huesos/diagnóstico por imagen , Femenino , Osteoporosis/diagnóstico por imagen , Ovariectomía , Hormona Paratiroidea/farmacología , Hormona Paratiroidea/uso terapéutico , Radiografía , Ratas , Ratas Sprague-DawleyRESUMEN
Pregnancy lowers the risk of breast cancer, largely attributable to alpha-fetoprotein (AFP). A small AFP-derived peptide (AFPep) which mimics the active site of AFP has been developed and may be useful for decreasing the risk of breast cancer for women. AFPep has been shown previously to stop the growth of estrogen-dependent human breast cancer xenografts in mice and prevent carcinogen-induced breast cancer in a rat model. Since AFPep disrupts an estrogen-responsive pathway, it is essential to assess its effects on the female reproductive cycle and fertility. Ten cycling female Sprague-Dawley rats (age 81 days) were given 100 microg AFPep in saline s.c. daily for 20 days. A second group of ten rats was given 50 microg tamoxifen s.c. daily and a third group received saline only. Vaginal smears were obtained twice per day and stained to assess estrous cycle phase. After completion of estrous cycle assessment (five cycles, 21 days), rats were maintained on drug and allowed to mate. Effects on birth of offspring and maternal body weights were assessed. AFPep had no significant effect on the incidence or duration of any estrous cycle phase, and no effect on reproductive potential or maternal body mass. Tamoxifen significantly increased the length of diestrus, locking the cycle in this phase for most animals. Only half of the tamoxifen-treated rats mated, and none became pregnant. Tamoxifen significantly slowed the rate of body mass increase. In rats, AFPep has no toxicity and no effect on female reproduction. This molecule may be developed into an attractive modality for prevention of breast cancer in women.