Heikinheimo O, Hsiu J G, Gordon K, Kim S, Williams R F, Gibbons W E, Hodgen G D
The Jones Institute for Reproductive Medicine, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA 23517, USA.
J Steroid Biochem Mol Biol. 1996 Oct;59(2):179-90. doi: 10.1016/s0960-0760(96)00113-6.
Continuous antiprogestin administration to hormone replaced, castrate monkeys inhibits estrogen-induced endometrial proliferation through mechanisms which remains unclear. To elucidate the molecular mechanisms of RU486-induced endometrial suppression, we treated six intact female cynomolgus monkeys on cycle days 2-22 sequentially with placebo, RU486 (1 mg/kg/day) and levonorgestrel (LNG) (2 microg/kg/day) intramuscularly (i.m.), with uterine wedge sections and endometrial biopsies collected on day 22 of each cycle. The uterine sections were evaluated for morphology, mitosis and proliferating cell nuclear antigen (PCNA) immunohistochemistry. Changes in the mRNA levels of ER, PR, cyclin-B and tumour suppressor gene p21 were assessed using co-amplification with beta-actin by reverse transcriptase-polymerase chain reaction (RT-PCR). Administration of RU486 uniformly resulted in characteristic suppression of endometrium with few mitosis, dense stroma and simple glands, whereas the effects of LNG were less uniform. Following RU486 administration, the levels of endometrial ER and PR mRNA were comparable to proliferative phase endometrium, and significantly higher than those seen in the secretory endometrium, indicating that some of the biological actions of E2 were not inhibited during RU486 treatment. Despite scarce mitosis, PCNA was readily detectable in all samples. Curiously, in comparison to secretory phase controls, the levels of cyclin-B, but not p21, mRNA were markedly increased following RU486. The effects of LNG on the levels of these mRNA species varied, with mean levels falling between those of the secretory phase controls, and RU486-treated specimens. The increase in cyclin-B mRNA and lack of mitosis suggests that anti-proliferative actions of RU486 in the primate endometrium might be associated with a cell-cycle block at the G2-M interphase. Whether mechanisms similar to these are associated with the beneficial clinical effects of RU486 seen in the treatment of various hormone dependent maladies remains to be determined.
对接受激素替代的去势猴子持续给予抗孕激素，通过尚不清楚的机制抑制雌激素诱导的子宫内膜增殖。为阐明米非司酮（RU486）诱导子宫内膜抑制的分子机制，我们在第2至22个周期日，对6只完整的雌性食蟹猴依次肌肉注射安慰剂、RU486（1毫克/千克/天）和左炔诺孕酮（LNG）（2微克/千克/天），并在每个周期的第22天采集子宫楔形切片和子宫内膜活检样本。对子宫切片进行形态学、有丝分裂和增殖细胞核抗原（PCNA）免疫组织化学评估。通过逆转录聚合酶链反应（RT-PCR）与β-肌动蛋白共同扩增，评估雌激素受体（ER）、孕激素受体（PR）、细胞周期蛋白B和肿瘤抑制基因p21的mRNA水平变化。给予RU486均能一致地导致子宫内膜特征性抑制，有丝分裂少、间质致密且腺体简单，而LNG的作用则不太一致。给予RU486后，子宫内膜ER和PR mRNA水平与增殖期子宫内膜相当，且显著高于分泌期子宫内膜，表明在RU486治疗期间，E2的一些生物学作用未被抑制。尽管有丝分裂稀少，但在所有样本中均易于检测到PCNA。奇怪的是，与分泌期对照相比，RU486处理后细胞周期蛋白B的mRNA水平显著升高，而p21的mRNA水平未升高。LNG对这些mRNA种类水平的影响各不相同，平均水平介于分泌期对照和RU486处理样本之间。细胞周期蛋白B mRNA的增加和有丝分裂的缺乏表明，RU486在灵长类动物子宫内膜中的抗增殖作用可能与G2-M间期的细胞周期阻滞有关。这些机制是否与RU486在治疗各种激素依赖性疾病中所见的有益临床效果相关，仍有待确定。
