The basic pathological changes of primary ovarian insufficiency (POI) include ovarian tissue fibrosis and follicular development disorders. The human umbilical cord mesenchymal stem cell (hUMSC) transplantation has been shown an effective method to improve the ovarian function in POI rat model; however, the exact mechanisms are still unclear. The purpose of this study is to investigate whether the recovery of ovarian function in POI rats is related to the inhibition of tissue fibrosis following hUMSC transplantation. Furthermore, the transforming growth factor-β1 (TGF-β1) signaling pathway is explored to determine the mechanisms of ovarian function recovery through its inhibition of tissue fibrosis. The primary ovarian insufficiency (POI) rat model was established by intraperitoneal injection of chemotherapy drug cisplatin (CDDP) for 7 days. The levels of serum sex hormones were measured using enzyme-linked immunosorbent assay (ELISA). The tissue fibrosis in the ovary was examined using Masson staining and Sirius red staining. The collagen fibers in the ovarian tissues were detected by Western blot analysis. To investigate the mechanisms of ovarian function recovery following hUMSC transplantation, ovarian stromal cells were isolated from the ovarian cortex of immature rats. The expression of Cytochrome P450 17A1 (Cyp17a1) and fibrosis marker of alpha smooth muscle actin (α-SMA) in ovarian stromal cells was examined using immunofluorescence analysis. Also, the protein levels of Cyp17a1 and α-SMA in ovarian stromal cells were examined by Western blot analysis. The expression of TGF-β1 and Smad3 signals was measured by Western blot and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis. The results show that the function of the ovary in POI rats was significantly improved after hUMSC transplantation. The expression of fibrosis markers (α-SMA) and production of Collagen Type I (Collagen I) and Collagen Type III (Collagen III) in POI rats were significantly inhibited in POI rats following hUMSC transplantation. In the cultured ovarian stromal cells, the decrease of TGF-β1 and p-Smad3 protein expression was observed in hUMSC-treated POI rats. The treatment with TGF-β1 inhibitor of SB431542 further confirmed this signal pathway was involved in the process. Our study demonstrated that the TGF-β1/Smad3 signaling pathway was involved in the inhibition of ovarian tissue fibrosis, which contributed to the restoration of ovarian function in POI rats following hUMSC transplantation.

中文翻译：

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hUMSC通过TGF-β1/ Smad3信号通路调节卵巢基质细胞的分化，抑制卵巢纤维化，修复POI大鼠卵巢功能。

原发性卵巢功能不全（POI）的基本病理变化包括卵巢组织纤维化和卵泡发育异常。人脐带间充质干细胞（hUMSC）移植已被证明是改善POI大鼠模型卵巢功能的有效方法。但是，确切的机制仍不清楚。这项研究的目的是调查hUMSC移植后POI大鼠卵巢功能的恢复是否与组织纤维化的抑制有关。此外，探索了转化生长因子-β1（TGF-β1）信号传导途径，以确定其通过抑制组织纤维化来恢复卵巢功能的机制。通过腹腔注射化疗药物顺铂（CDDP）7天建立原发性卵巢功能不全（POI）大鼠模型。使用酶联免疫吸附测定（ELISA）测量血清性激素水平。使用Masson染色和Sirius红染色检查卵巢中的组织纤维化。通过蛋白质印迹分析检测卵巢组织中的胶原纤维。为了研究hUMSC移植后卵巢功能恢复的机制，从未成熟大鼠的卵巢皮质中分离出卵巢基质细胞。使用免疫荧光分析检查细胞色素P450 17A1（Cyp17a1）和α平滑肌肌动蛋白（α-SMA）在卵巢基质细胞中的表达。此外，通过蛋白质印迹分析检查了卵巢基质细胞中Cyp17a1和α-SMA的蛋白水平。通过Western印迹和定量逆转录聚合酶链反应（qRT-PCR）分析测量TGF-β1和Smad3信号的表达。结果表明，hUMSC移植后，POI大鼠卵巢功能明显改善。在hUMSC移植后，POI大鼠中POI大鼠的纤维化标记（α-SMA）的表达以及I型胶原（I型胶原）和III型胶原（III型胶原）的产生受到显着抑制。在培养的卵巢基质细胞中，在经hUMSC处理的POI大鼠中观察到TGF-β1和p-Smad3蛋白表达的降低。用SB431542的TGF-β1抑制剂治疗进一步证实了该信号通路参与了该过程。我们的研究表明，TGF-β1/ Smad3信号通路与抑制卵巢组织纤维化有关，