基于纳米SPIO的宫腔粘连内膜损伤与修复的MR研究

Intrauterine adhesions (IUA) is the second-largest cause of secondary infertility in women. It occurs mostly as a result of trauma, particularly associated with the degree of endometrial damage. There aren’t ideal prevention and treatment methods on IUA by now; It has been confirmed by experiments that there are stem cells in menstrual blood (menstrual blood-derived mesenchymal stem cells, MenSCs). These cells can be induced to differentiate into endometrial cells and obtained noninvasively. MenSCs may play a functional role in the regeneration of endometrium.; Ferumoxytol is FDA-approved agent used for treatment of iron deficiency in patients with anemia. It provides a strong signal on MR images. The authous hypothesize that this clinically applicable iron oxide nanopartical compound can be used as a stem cell marker. It is possible to develop an immediately clinically applicable MRI test for in vivo tracking of Ferumoxytol-labeled MenSCs engraftment outcomes noninvasively on endometrial repair. Peristaltic endometrium may be associated with pregnancy and it can be monitored with MR dynamic movie sequences. The changes of endometrial peristalsis may be associated with endometrial damage and repair. Here the authous intend to use Ferumoxytol as molecular probe for MR tracking. We plan to explore the feasibility and potential mechanism of endometrial repair with MenSCs, and use MR imaging to follow-up endometrial peristalsis at different time points before and after transfusion of MenSCs. This study is to investigate the stem cells based theatment of IUA using MR cellular imaging in vivo noninvasively and dynamically. This novel molecular imaging method is possible to provide theory basis and experimental data for the prevention and repairment of IUA, which may provide new ideas and new ways to the cell therapy of IUA.

宫腔粘连（IUA）是引起女性继发不孕的第二大病因，发病与子宫内膜损伤相关，目前国内外均无理想的预防及治疗方法；经血中含有干细胞（MenSCs），该干细胞可诱导分化为内膜细胞，且无创获得，有可能成为修复IUA损伤内膜的种子细胞；Ferumoxytol是FDA认证的临床用药，有良好的超顺磁性，若将MenSCs与Ferumoxytol复合物结合就有可能在活体状态下用磁共振（MR）对IUA内膜修复进行特异性的细胞成像；子宫内膜的蠕动可能与受孕相关，MR动态电影序列可监测，内膜蠕动的变化可能与IUA损伤、修复相关。本项目拟用Ferumoxytol为MR示踪剂，对以上假设进行实验，在细胞和分子水平观察IUA的发生、修复与转归，探讨MenSCs修复IUA损伤内膜的可行性及其作用机制；应用MR监测IUA治疗前后子宫内膜蠕动的变化并阐明其可能机制，为IUA的预防、细胞治疗及分子影像学示踪与评估提供实验基础。

本研究分离、培养、纯化经血源性间充质样干细胞，进行干细胞特性的多方面鉴定，结果表明，研究中分离纯化的细胞，在形态特征、表面标记物、超微结构、细胞周期及增殖分化能力等方面符合间充质干细胞的生物学特性，具有干细胞的特性，能够在体外增殖、分化为成骨、成脂细胞，为下一步的实验研究打下了基础；瑞存与PLL的结合物NP-PLL在低标记浓度（200μg/ml）下，孵育18~24小时即可简便、有效的标记经血源性间充质样干细胞，并可在体外进行细胞群的MR成像，为进一步的活体示踪实验奠定了重要的基础；使用纳米磁粒子复合物NP-PLL标记细胞，在低浓度（200μg/ml）时对细胞毒性小，不改变经血源性间充质样干细胞的功能、增殖、分化等生物学特性，不影响细胞表面标记物的表达，可用于移植细胞的活体示踪研究；内膜机械损伤加感染可以成功的建立新西兰兔子宫内膜损伤的宫腔粘连模型，该模型符合以创伤和感染为高危致病因素的宫腔粘连的发病机制研究要求，重复性好。MR成像可间接评价标记的移植干细胞在损伤局部的分布情况。由于新西兰兔子宫体积较小，腹腔肠气影响大，正常子宫难以在临床用MR仪上清晰显示。