Objective To study the effects of 17β -estradiol (E2) on the regulation of the proliferation of condylar chondrocytes and provide a preliminary discussion on the role of phosphorylate-mammalian target of rapamycin (pmTOR) in this regulatory process. Methods Condylar chondrocytes were isolated from 6-week-old female rats for primary culture. Drug treatment with different concentrations of E2 and/or rapamycin (RAPA) was carried out on secondgeneration cells. Cell Counting Kit 8 was used to measure the cell viability of condylar chondrocytes after culture for 24, 48, or 72 h, and reverse transcription-polymerase chain reaction (RT-PCR) was applied to detect the relative gene expression of estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), collagen type Ⅱ (COLⅡ), autophagy-related gene 6 (Beclin-1), and autophagy-related gene 5 (ATG-5). Western blot was employed to determine the relative protein expression of ERα, ERβ, Beclin-1, lipid-modified light chain 3B (LC3-Ⅱ), and p-mTOR. Results E2 could significantly promote the proliferation of chondrocytes cultured in vitro, and maximum promotion was achieved at a concentration of 10 -8 mol·L -1 . RAPA could significantly inhibit cell proliferation. E2 at aconcentration of 10 -8 mol·L -1 could greatly improve the gene expression levels of ERα and COLⅡ (P<0.01) with the protein levels of ERα and p-mTOR (P< 0.05), and decrease the gene expression levels of Beclin-1 and ATG-5 (P<0.05) with the protein levels of Beclin-1 and LC3-Ⅱ (P<0.05). RAPA could also enhance the relative protein expression of Beclin-1 and LC3-Ⅱ (P<0.01), and reduce the expression of p-mTOR (P<0.01). Treatment with the ERα antagonist significantly reduced the expression of pmTOR in cells (P<0.01). Conclusion At a concentration of 10 -8 mol·L -1 , E2 could effectively activate the phosphorylation of mTOR through the ERα-p-mTOR pathway, inhibit cell autophagy, and promote the proliferation of condylar chondrocytes. [ABSTRACT FROM AUTHOR]

目的研究17β-雌二醇（E2） 对髁突软骨细胞增殖调节的影响, 并初步探讨磷酸化雷帕霉素哺乳动物 靶标（p-mTOR） 在该调节过程中发挥的作用。方法取6 周龄雌性SD大鼠髁突软骨细胞进行原代培养, 从第 二代分别给予不同浓度的E2 和/或雷帕霉素（RAPA）;CCK8 法检测不同给药条件下, 髁突软骨细胞在第24、 48、72 小时的增殖情况;逆转录聚合酶链式反应（RT-PCR） 检测软骨细胞中雌激素受体α （ERα）、雌激素受体 β （ERβ）、自噬相关基因6 （Beclin-1）、自噬相关基因5 （ATG-5）、Ⅱ型胶原（COLⅡ） 相关基因的表达;蛋白 印迹（Western blot） 法检测软骨细胞中ERα、ERβ、Beclin-1、脂质化轻链蛋白3B （LC3-Ⅱ）、p-mTOR 相关蛋 白的表达及加入雌激素受体拮抗剂后各组细胞p-mTOR的表达。结果E2 可显著促进体外培养的髁突软骨细胞 增殖, 并在10 -8 mol·L -1 浓度下达到峰值;RAPA 可以显著抑制细胞增殖。10 -8 mol·L -1 E2 上调软骨细胞ERα、 COLⅡ基因表达（P<0.01） 和ERα、p-mTOR蛋白表达（P<0.05）, 下调软骨细胞Beclin-1、ATG-5 基因表达（P< 0.05） 和Beclin-1、LC3-Ⅱ蛋白表达（P<0.05）;RAPA可以上调细胞Beclin-1 和LC3-Ⅱ蛋白水平（P<0.01）, 下 调p-mTOR 的表达（P<0.01）;ERα 拮抗剂可以显著降低细胞中p-mTOR 的表达（P<0.01）。结论E2 在浓度为 10 -8 mol·L -1 时可有效通过ERα-p-mTOR途径激活mTOR的磷酸化, 抑制自噬, 提高髁突软骨细 胞增殖速度. [ABSTRACT FROM AUTHOR]

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