Hormone replacement reduces elevated in vivo venous tone in hypertensive ovariectomized rats

OBJECTIVE: The venous system may play a role in the development and progression of postmenopausal hypertension. In the present study, we investigated the effect of chronic angiotensin II-induced hypertension on the geometric, elastic, and contractile properties of the saphenous vein in sex hormone deficient and replaced female rats. METHODS: Thirty Sprague-Dawley rats were ovariectomized (n = 10), ovariectomized and angiotensin-infused (n = 10), or ovariectomized plus angiotensin-infused and hormone replaced with estradiol and medroxyprogesterone (n= 10). After 4 weeks, the saphenous veins were removed and cylindrical segments of the vessels were placed into a microangiograph and cannulated at both ends. Intraluminal pressure versus outer diameter curves were registered in Krebs-Ringer solution, in maximal norepinephrine contraction, and in full papaverine relaxation. RESULTS: In vivo venous tone of the saphenous vein in ovariectomized plus angiotensin-infused animals was significantly higher than in ovariectomized animals without angiotensin treatment (27.2 +/- 3.7% versus 5.3 +/- 2.1%, respectively; P <.05). Hormone replacement restored venous tone (9.6 +/- 3.4%; P <.01). In vitro pressure-induced myogenic tone was markedly reduced by chronic angiotensin infusion, which was partially reversed by hormone replacement. Passive incremental distensibility was lowered after angiotensin infusion independently of the sex hormone state. CONCLUSION: Hormone replacement improved venous contractility (rapid adaptation response), which was seen as decreased in vivo venous tone, but venous distensibility (chronic adaptation) was not improved by hormone replacement in our short-term study. We demonstrate beneficial short-term effects of hormone replacement on the venous system in our model of postmenopausal hypertension. Further studies might be warranted to see whether long-term benefits can be achieved.     

Influence of pubococcygeal repair on urethral closure pressure at stress

Stress incontinence is cured or improved by surgical treatment but the immediate reason is obscure. Simultaneous urethrocystometry with urethral pressure profile recording at rest pre- and postoperatively has shown that the urethral pressure remains fairly unchanged by the operation. Similar measurements, but during stress, have been performed in eight women with stress incontinence before and after pubococcygeal repair with interest focussed on changes in pressure transmission from abdomen to urethra. We have found that the reason for cure is a greatly improved pressure transmission, probably depending on the firm support beneath the urethra postoperatively. Rotational descent is prevented and the "floor" beneath the urethra responds with good counterpressure at stress. The pressure transmission was as good at one year as at one month after surgery, pointing to a lasting result.     

A promising protein responsible for overactive bladder in ovariectomized mice

Objective

Ovariectomy (OVX) in mice is a model mimicking a neuro-electronic proof of an overactive bladder in postmenopausal women. Overactive bladder (OAB) was recently found to be due to an altered gap junction protein in a rat model. Thus, this study was conducted to evaluate changes in cell junction protein expression and composition in the bladder of OVX mice.

Comparative effects of estradiol, raloxifene, and genistein on the uterus of ovariectomized mice

To explore the uterine effects of administration of compounds that exert their bone-sparing functions through estrogen receptors, we administered 17beta-E2, raloxifene, or genistein to ovariectomized mice and analyzed the uterus weight and histology 4 weeks after beginning the treatments. Results indicated that raloxifene and genistein have partial agonistic properties on the uterus in estrogen-depleted mice, and that genistein induced apoptosis and several atypias in the glandular epithelium of endometrium, as demonstrated in hematoxylin-eosin-stained histological sections.     

Concentration of glycosaminoglycan in ovariectomized mice uterus after treatment with ovarian steroids

The aim of this study was to evaluate the amount of non- and sulfated glycosaminoglycans in the ovariectomized mice uterus, after treatment with ovarian steroids. For this purpose, 50 adult female mice were divided into five groups with 10 animals/each: control group: CG (ovary intact), and ovariectomized groups: OG (vehicle), EG (estradiol), PG (progesterone) and EPG (estradiol combined to progesterone). The treatments started 30 days after ovariectomy. All the animals were treated for 50 consecutive days. These hormones were administered in a sterile oily solution via gavage. Twenty-four hours after the last treatment, all animals were euthanized, removing the uterine horn for biochemical analyses. To quantify, the hyaluronic acid (HA) used ELISA-like fluorometric assay, and the sulfated glycosaminoglycans (GAGs) used agarose gel electrophoresis. The amount of HA was significantly higher in the group treated with progesterone (PG) compared to the others groups (p?p?p?相似文献   

Successful pregnancy in ovariectomized mice using a combination of heterotopic autotransplantation of ovarian tissues and embryo transfer

Aim:  The present report is the first to show that, after ovariectomy, female mice with autotransplanted ovarian sections can maintain pregnancy after embryo transfer (ET) independent of the transplantation site.
Methods:  Three-month-old ICR females were ovariectomized, and sections from their own ovaries were transplanted either under their kidney capsule (KC group) or into a subcutaneous space (SC group) just after ovariectomy. In vitro fertilized blastocysts were transferred into uterine horns of the pseudopregnant mice that had received the transplanted ovarian tissues. Cesarean sections were carried out 17 days after ET to deliver any live fetuses that were present, and the numbers of implantation sites and fetuses were noted. Transplanted ovarian sections were removed and fixed for histological analysis.
Results:  Of the 10 mice in the KC group that received 107 blastocysts, two females (20%) became pregnant; they showed 12 implantation sites (11.2%) and produced four pups (3.7%). In the SC group, 101 blastocysts were transferred to eight females, and three females (37.5%) became pregnant; there were seven implantation sites (6.9%), and three pups (3.0%) were born. There were no statistically significant differences between the two groups in any of the parameters evaluated. On histological examination, luteinization and vascularization of the ovarian sections that were transplanted in the pregnant SC and KC females were noted.
Conclusion:  The pregnancy and full-term fetal development were obtained in ovariectomized mice using a combination of heterotopic ovarian tissue autotransplantation and transfer of embryos produced by in vitro fertilization.     

Effects of tibolone on sulfatase pathway of estrogens metabolism and on growth of MCF-7 human breast tumors implanted in ovariectomized nude mice

BACKGROUND: The benefits of estrogen plus progestin in healthy post-menopausal women remain uncertain. Tibolone, with its in vitro documented inhibitory effects on estrogens metabolism and its selective action on breast, may be an alternative that could favorably influence the health benefit of hormone replacement therapy. METHODS: We studied the effect of tibolone on the tumor growth of MCF-7 cells implanted in 40 ovariectomized nude mice, receiving subcutaneous pellets of 17beta-estradiol, estrone, estrone-sulfate or vehicle, and daily gavages of tibolone or placebo. RESULTS: Tibolone, although used at high dose, did not stimulate nor inhibit the estrogen-induced tumors, nor the tumors in estrogen-deprived mice. Measurements of plasma levels of estrogens indicated that tibolone potently stimulated sulfotransferase activity, but intra-tumor levels of estrogens were not significantly modified by tibolone. CONCLUSIONS: This in vivo study performed with high dose of orally administered tibolone that allowed its hepatic conversion into active metabolites has shown no significant effect on breast tumors growth. Tibolone increased the circulating sulfated estrogens by its activity on the hepatic sulfation but not the intra-tumor levels of estrogens (free or sulfated). However, further studies of dose-response curve and molecular markers are needed to exclude definitely a stimulatory effect of tibolone on tumor growth.     

Influence of ionizing radiation on fetoplacental growth in mice.

The effects of single doses of 60Co whole-body irradiation were studied in about 600 inbred primiparous Swiss-Webster mice on gestational day 9, 10, 11, or 12. The embryos and their placentas were weighted from day 13 to 18. A reference model surveyed the response of the conceptus to varying doses. A significant reduction in the fetal wet weight was observed as follows: day 9, 150-175 r.; day 10, 125-150 r.; day 11, 75-175 r.; day 12, 125-450 r. Beyond the upper-limit doses, a high mortality rate was detected, i.e., 64.5 per cent on day 10 at 175 r. and 63 per cent on day 11 at 200 r. The rapid growth period of the placenta extended from day 13 to 15. By this latter stage it had practically reached its maximum development. The placental index decreased progressively from day 13 to 18; however, this index was higher than the control on day 12 in treated animals, while lower on day 9, 10, or 11.     

Stress urinary incontinence following vaginal trauma involves remodeling of urethral connective tissue in female mice

Objective

The molecular mechanisms underlying stress urinary incontinence (SUI) are not clear. This study was conducted to evaluate molecular alterations in the urethras of mice with experimentally induced SUI.

Study design

Eighteen virgin female mice were equally distributed into three groups as follows: two groups undergoing vaginal distension (VD) for 1 h with 3 mm and 8 mm dilators each, and a non-instrumented control group. Changes in leak point pressure (LPP), morphology, lysyl oxidase (LOX) expression and the metabolism of urethral connective tissue were assessed.

Results

The LPP was significantly decreased in the 3 mm and 8 mm VD groups compared with that in the control group. Collagen and elastin expression in the urethra was significantly decreased in the 8 mm VD group compared with that in the control group, while LOX expression was significantly enhanced.

Conclusions

SUI following vaginal trauma involves over-expression of LOX and decreased synthesis of extracellular matrix components or increased proteolysis in the urethra.     

Comparison of necrosis in human ovarian tissue after conventional slow freezing or vitrification and transplantation in ovariectomized SCID mice

This paper examines and compares necrosis in human ovarian tissue after conventional slow freezing or vitrification and ensuing xenotranplantation. Slow cryoconserved or vitrified ovarian tissue samples and fresh controls from nine patients were subcutaneously transplanted into SCID mice. The tissue samples were explanted after 6 weeks and the necrotic areas were examined by staining with Lucifer yellow SV. The size of the necrotic areas in parallel cultivated ovarian tissue samples was compared, as was necrosis in cultivated prostate tumour spheroids where the emergence of necrosis and its pathophysiological correlation have been described. Examinations showed no significant rise in the proportion of necrotic areas after slow cryoconservation/transplantation and in the controls (transplanted fresh tissue, not transplanted fresh tissue, long-term culture). The proportion of necrotic areas in the tumour spheroids was significantly higher than in the ovarian tissue. Vitrification could, after these results, be presented as an alternative to conventional slow cryoconservation.     

The effects of raloxifen on depression and cognition in ovariectomized rats

This study investigates the effects of raloxifen on cognition and depression in an animal model.     

雷洛昔芬和依普黄酮对去卵巢大鼠骨干力学的影响

目的:研究雷洛昔芬和依普黄酮对切除成熟卵巢大鼠骨干生物力学性能的影响,探讨此两种药物治疗绝经后骨质疏松症的疗效。方法:选用6月龄未交配健康雌性Sprague-Dawley大鼠50只,随机分为5组,每组10只:(1)假手术组(sham);(2)骨质疏松组(OVX);(3)OVX加戊酸雌二醇组(Valerate Estriol,E_2;0．8mg·kg~(-1)·d~(-1));(4)OVX加雷洛昔芬组(Raloxifene,RLX;5mg·kg~(-1)·d~(-1));(5)OVX加依普黄酮组(Ipriflavone,IPR; 100mg·kg~(-1)·d~(-1));于去势手术3周后开始按分组设计喂药(灌胃),治疗3个月后处死。取大鼠右股骨及第三腰椎测定骨密度;然后对右股骨中段进行三点弯曲试验,测定多个股骨干生物力学指标。结果:(1)骨密度:OVX组椎骨及股骨干骺端密度明显下降,使用E_2和RLX能够显著提升骨密度;但股骨干密度各组间差异无统计学意义;(2)骨干生物力学性能:三点弯曲实验结果显示,OVX组股骨干生物力学指标较sham组明显下降,用RLX和IPR治疗与E_2一样可阻止这种变化(P＜0．05)。结论:雷洛昔芬和依普黄酮能阻止卵巢切除所致的成熟雌性大鼠股骨干(皮质骨)生物力学性能受损。