基于人小唾液腺干细胞的类器官修复小鼠放射性唾液腺损伤

Radioactive salivary gland injury is a common complication of radiotherapy for head and neck cancer. Currently there is no effective method for treatment. Bioengineered salivary gland organoids should be required for patients with massive salivary tissue atrophy. however, the capability of these methods to generate salivary gland tissue of sufficient size, and resembling that induced by natural gland organogenesis has not been achieved. In addition, shortage of such cell source is one of the major concerns, Consequently, attempts to regenerate functional salivary glands have to face a challenge to find a cell source for replacing the damaged tissues and cells. Previously We discovered and reported human minor salivary gland epithelial stem/progenitor cells and mesenchymal stem cells. Therefore, we hypothesized that minor salivary gland derived mesenchymal stem cells (MSCs) could be used as feeder cells to induce minor salivary gland epithelial stem/progenitor cells self-assembly and branching and forming salivary gland organoids for Radioactive salivary gland injury treatment. In this study, human minor salivary gland epithelial stem/progenitor cells combined mesenchymal stem cells were cultured with three-dimensional culture in vitro, and transplanted into mouse salivary gland damaged by radiation. Then the examinations were made by histological and molecular biological techniques, to explore the feasibility and mechanism of salivary gland organoids and repair for radiation induced xerostomia.

放射性唾液腺损伤是头颈肿瘤放疗常见并发症，目前无有效治疗方法。对严重的唾液腺损伤，需用再生的唾液腺来替代损害的腺体。唾液腺是通过上皮—间充质相互作用形成。再生充分大小、类似于天然腺器官形成的唾液腺的方法尚未建立。种子细胞来源短缺是主要挑战。过去，我们在国际上首次报道了人小唾液腺上皮干/祖细胞和多能间充质干细胞。因此，我们提出假说：基于人小唾液腺上皮干/祖细胞及其间充质干细胞联合3D培养构建唾液腺类器官并用于修复鼠唾液腺放射性损伤的研究。目前尚无有关报道。我们的前期研究表明：与单用上皮干/祖细胞比较，这两种小唾液腺干细胞联合三维培养形成的类器官体积较大、形态结构良好、表达相应免疫表型。本研究拟采用人小唾液腺上皮干/祖细胞和间充质干细胞联合三维培养构建唾液腺类器官、体内移植于小鼠放射性损伤的唾液腺，通过组织细胞学和分子生物学方法等检测分析，探索唾液腺类器官形成机制及其治疗放疗性口干症的作用。

为了修复临床放射治疗头颈部肿瘤导致的严重唾液腺损伤，我们计划利用人小唾液腺组织构建唾液腺类器官来替代受损伤的腺体。前期研究主要基于人小唾液腺上皮干/祖细胞及其间充质干细胞联合三维培养构建唾液腺类器官，但是上皮干/祖细胞来源短缺和体外上皮干性维持困难仍然限制着课题进展。为此，我们利用唇部手术废弃的人小唾液腺组织直接消化处理三维培养并不断优化培养条件，成功地在体外构建了结构和功能完善并能稳定传代的唾液腺类器官。我们的研究结果表明：与前期小唾液腺上皮干/祖细胞及其间充质干细胞联合三维培养相比，直接消化并三维培养的唾液腺类器官具有明显优势。首先，改善后的类器官具备稳定传代其很好地解决了干细胞来源短缺和干性维持问题。其次，相比之下，改善后的类器官结构分化更接近正常组织并且功能反应更完备。最后，体内移植改善后的类器官于小鼠放射性损伤的唾液腺更具前景和治疗效果。