Department of Obstetrics and Gynecology, Nanjing Maternity and Child Health Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
Contraception. 2010 Sep;82(3):301-8. doi: 10.1016/j.contraception.2010.03.002. Epub 2010 Apr 13.
The levonorgestrel intrauterine system (LNG-IUS) is a widely recognized intrauterine anti-fertility system, which can alleviate symptoms of uterine leiomyoma. This study aims to evaluate leimyoma cell growth inhibition induced by high concentrations of LNG.
After treatment with LNG, the growth rate of the cultured primary uterine leiomyoma cells was studied with methyl thiazolyl tetrazolium (MTT) assay. Cell apoptosis rate was determined by morphological changes and flow cytometry. Reverse transcription polymerase chain reaction (RT-PCR) and Western blotting were performed to measure the differential mRNA and protein expression levels.
The proliferation rate of uterine leiomyoma cells was suppressed after treatment with LNG at a minimum concentration of 10 mcg/mL. The inhibitive effect was positively correlated with the LNG concentration and with the incubation time. Flow cytometry showed that the apoptosis rate was increased with the LNG concentration. The mRNA levels of IGF-1, Bcl-2 and survivin were down-regulated significantly after treatment with 10 mcg/mL LNG. Western blot analysis confirmed that the expression of Bcl-2 and survivin was decreased significantly, and the p38 phosphorylation level was increased and caspase 3 was activated remarkably 72 h after treatment with 10 and 20 mcg/mL LNG.
This study demonstrated that LNG may suppress the proliferation and induce apoptosis of the uterine leiomyoma cells.
左炔诺孕酮宫内节育系统（LNG-IUS）是一种广泛认可的宫内节育系统，可缓解子宫肌瘤的症状。本研究旨在评估高浓度 LNG 对子宫肌瘤细胞生长的抑制作用。
用甲基噻唑基四唑（MTT）测定法研究 LNG 处理后培养的原发性子宫肌瘤细胞的生长速度。通过形态变化和流式细胞术测定细胞凋亡率。采用逆转录聚合酶链反应（RT-PCR）和 Western blot 测定差异 mRNA 和蛋白表达水平。
LNG 最低浓度为 10 mcg/mL 时，子宫肌瘤细胞的增殖率受到抑制。抑制作用与 LNG 浓度和孵育时间呈正相关。流式细胞术显示，随着 LNG 浓度的增加，凋亡率增加。用 10 mcg/mL LNG 处理后，IGF-1、Bcl-2 和 survivin 的 mRNA 水平显著下调。Western blot 分析证实，用 10 和 20 mcg/mL LNG 处理 72 小时后，Bcl-2 和 survivin 的表达显著下调，p38 磷酸化水平升高，caspase 3 激活明显。
本研究表明，LNG 可能抑制子宫肌瘤细胞的增殖并诱导其凋亡。
