Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Thyroid. 2021 Apr;31(4):638-648. doi: 10.1089/thy.2020.0088. Epub 2021 Jan 5.
Graves' orbitopathy (GO) is the most common and serious manifestation of Graves' disease (GD). It is characterized by orbital inflammation and tissue remodeling. Although several GO models have been reported, most lack a full assessment or mechanistic evaluation. Here, we established a promising mouse model mimicking many aspects of human GO with a frequency of 70% and characterized the key role of T cells in the progression of GO. An adenovirus expressing the human thyrotropin (TSH) receptor A subunit (Ad-TSHRA) was injected in the muscles of female BALB/C mice nine times to induce GO. At predetermined time points, histological examinations of retrobulbar tissues and thyroid glands were performed to dynamically monitor changes; serum autoantibodies and total thyroxine levels were examined to evaluate thyroid function. Flow cytometry of CD4+ T cell subgroups and RNA sequencing (RNA-Seq) of splenocytes were also performed to explore the underlying mechanism. After nine injections, 7 of 10 mice challenged with Ad-TSHRA developed the orbital changes associated with GO. Seven mice manifested retrobulbar fibrosis, and four mice showed adipogenesis. Exophthalmia, conjunctival redness, and orbital lymphocyte infiltration were also observed in a subset of mice. The orbitopathy was first detected after seven injections and followed the hyperplastic change observed in thyroids after four injections. Flow cytometry revealed increased proportions of Th1 cells and decreased proportions of Th2 cells and regulatory T (Treg) cells in the splenocytes of GO mice. This change in CD4+ T cell subgroups was confirmed by orbital immunohistochemical staining. Genes involved in T cell receptor signaling, proliferation, adhesion, inflammation, and cytotoxicity were upregulated in GO mice according to the RNA-Seq; a trend of upregulation of these GO-specific genes was observed in mice with hyperthyroidism without orbitopathy after four injections. A GO mouse model was successfully established by administering nine injections of Ad-TSHRA. The model was achieved with a frequency of 70% and revealed the importance of T cell immunity. A potential time window from Graves' hyperthyroidism to GO was presented for the first time. Therefore, this model could be used to study the pathogenesis and novel treatments for GO.
格雷夫斯眼病（GO）是格雷夫斯病（GD）最常见和最严重的表现。它的特征是眼眶炎症和组织重塑。尽管已经报道了几种 GO 模型，但大多数模型缺乏全面评估或机制评估。在这里，我们建立了一种有前途的小鼠模型，该模型在 70%的频率下模拟了许多人类 GO 的特征，并证实了 T 细胞在 GO 进展中的关键作用。 我们将表达人促甲状腺激素（TSH）受体 A 亚单位的腺病毒（Ad-TSHRA）注射到雌性 BALB/C 小鼠的肌肉中九次，以诱导 GO。在预定的时间点，对眼眶组织和甲状腺进行组织学检查，以动态监测变化；检查血清自身抗体和总甲状腺素水平，以评估甲状腺功能。还进行了 CD4+T 细胞亚群的流式细胞术和脾细胞的 RNA 测序（RNA-Seq），以探索潜在的机制。 在九次注射后，接受 Ad-TSHRA 挑战的 10 只小鼠中有 7 只出现了与 GO 相关的眼眶变化。7 只小鼠表现出眼眶纤维化，4 只小鼠表现出脂肪生成。在一部分小鼠中还观察到眼球突出、结膜发红和眼眶淋巴细胞浸润。眼眶病最早在七次注射后检测到，随后在四次注射后观察到甲状腺的增生性变化。流式细胞术显示 GO 小鼠脾细胞中 Th1 细胞比例增加，Th2 细胞和调节性 T（Treg）细胞比例减少。眼眶免疫组织化学染色证实了 CD4+T 细胞亚群的这种变化。根据 RNA-Seq，GO 小鼠中涉及 T 细胞受体信号、增殖、黏附、炎症和细胞毒性的基因上调；在四次注射后没有眼眶病的甲状腺功能亢进小鼠中，观察到这些 GO 特异性基因的上调趋势。 通过给予九次 Ad-TSHRA 注射，成功建立了 GO 小鼠模型。该模型的建立频率为 70%，揭示了 T 细胞免疫的重要性。首次提出了从格雷夫斯甲状腺功能亢进到 GO 的潜在时间窗口。因此，该模型可用于研究 GO 的发病机制和新的治疗方法。
