Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.
Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany,
J Innate Immun. 2021;13(1):49-59. doi: 10.1159/000509716. Epub 2020 Sep 9.
To investigate immunological differences and the role of CD38+/F4/80 + M1 macrophages in C57BL/6J- and BALB/c-recipient mouse corneal transplantation models.
Allogeneic transplantation was performed crosswise in BALB/c mice and C57BL/6J mice; syngeneic transplantation was performed in both strains. Anterior chamber depth (ACD) was measured before and central corneal thickness (CCT) was measured both before and after transplantation. In vivo graft rejection was monitored using anterior eye segment optical coherence tomography (ASOCT) evaluating the CCT and grading of corneal oedema using a well-established clinical score (CS). Histology of corneal grafts was performed 18 or 21 days after surgery. Immunohistochemistry with anti-F4/80 antibody and anti-CD38 antibody was used for detecting M1 macrophages within the grafts.
High CS and CCT values after allogeneic transplantation persisted in both BALB/c (n = 18) and C57BL/6J recipients (n = 20). After syngeneic transplantation, CS and CCT values increased in both models in the early phase after surgery due to the surgical trauma. Surprisingly, in the syngeneic C57BL/6J model, high CCT values persisted. Furthermore, anterior synechiae developed in C57BL/6 recipients after both syngeneic and allogeneic transplantation, whereas BALB/c recipients showed almost no synechiae - even though C57/BL6J animals tended to have a deeper anterior chamber (281 ± 11 pixels [mean ± SD]) compared with BALB/c animals of the same age (270 ± 9 pixels [mean ± SD]). Immunohistochemistry revealed numerous CD38+/F4/80 + M1 macrophages in grafts of C57BL/6J recipients following both syngeneic and allogeneic transplantation. However, in BALB/c-recipient mice only sparse M1 macrophages were detectable (CD38 + M1 macrophages relative to all F4/80 + cells: 75 vs. 17% [after allogeneic transplantation] and 66 vs. 17% [after syngeneic transplantation]; p < 0.05).
Allogeneic corneal transplants are rejected in BALB/c as well as C57BL/6J mice, but tissue alterations with anterior synechiae are more pronounced in C57BL/6J recipients. Following syngeneic transplantation, C57BL/6J-recipient animals show a persistent graft swelling with increased numbers of CD38+/F4/80 + M1 macrophages in grafted tissue, in contrast to the common model using BALB/c-recipient mice. Our data strongly suggest that strain-dependent differences convey different innate immune responses in BALB/c and C57BL/6J strains. Accordingly, in murine keratoplasty experiments, the mouse line of both donor and recipient animals must be carefully considered. C57BL/6J-recipient mice might be particularly suited to study corneal graft rejection in a clinical setting considered "high risk."
研究 CD38+/F4/80+M1 巨噬细胞在 C57BL/6J 和 BALB/c 受体小鼠角膜移植模型中的免疫差异和作用。
在 BALB/c 小鼠和 C57BL/6J 小鼠之间进行同种异体移植；在两种品系中进行同基因移植。在移植前测量前房深度（ACD），在移植前后测量中央角膜厚度（CCT）。使用前节光学相干断层扫描（ASOCT）监测活体移植物排斥，评估 CCT，并使用成熟的临床评分（CS）评估角膜水肿的分级。术后 18 或 21 天进行角膜移植物的组织学检查。使用抗 F4/80 抗体和抗 CD38 抗体进行免疫组织化学染色，以检测移植物内的 M1 巨噬细胞。
在 BALB/c（n=18）和 C57BL/6J 受体（n=20）中，同种异体移植后 CS 和 CCT 值高的情况持续存在。在同基因移植后，由于手术创伤，两种模型在术后早期 CS 和 CCT 值均升高。令人惊讶的是，在同基因 C57BL/6J 模型中，高 CCT 值持续存在。此外，C57BL/6 受体在同种异体和同基因移植后均发生前粘连，而 BALB/c 受体几乎没有粘连 - 尽管 C57/BL6J 动物的前房深度（281±11 像素[均值±标准差]）比同年龄的 BALB/c 动物（270±9 像素[均值±标准差]）深。免疫组织化学显示，在 C57BL/6J 受体的同种异体和同基因移植后，均可见大量 CD38+/F4/80+M1 巨噬细胞。然而，在 BALB/c 受体小鼠中，仅可检测到稀疏的 M1 巨噬细胞（CD38+M1 巨噬细胞相对于所有 F4/80+细胞：同种异体移植后为 75%比 17%；同基因移植后为 66%比 17%；p<0.05）。
同种异体角膜移植在 BALB/c 和 C57BL/6J 小鼠中均被排斥，但 C57BL/6J 受体的组织改变更明显，前粘连更多。在同基因移植后，C57BL/6J 受体动物的移植物肿胀持续存在，移植物组织中 CD38+/F4/80+M1 巨噬细胞数量增加，与使用 BALB/c 受体小鼠的常见模型形成对比。我们的数据强烈表明，品系依赖性差异在 BALB/c 和 C57BL/6J 品系中引起不同的固有免疫反应。因此，在进行小鼠角膜移植实验时，必须仔细考虑供体和受体动物的鼠种。C57BL/6J 受体小鼠可能特别适合研究临床认为“高风险”的角膜移植物排斥反应。
