Department of Ophthalmology, University of Düsseldorf, Düsseldorf, Germany.
Invest Ophthalmol Vis Sci. 2010 Sep;51(9):4831-9. doi: 10.1167/iovs.09-4923. Epub 2010 Apr 30.
Microglia cells have been associated with immunologic defense and repair. The course of retinal disease after lethal irradiation for bone marrow depletion and substitution was evaluated with respect to macrophage and microglial involvement.
Lethal irradiation in C57BL/6 mice was conducted with a low-voltage radiation unit. The animals were randomized to shielded or unshielded radiation and subsequently received transplants of GFP+ bone marrow cells (beta-actin promoter). The GFP transformation rate was analyzed by flow cytometry. GFP+ cells in the retina were examined for co-localization with macrophage and dendritic cell markers at various time points between 1 and 7 months after irradiation. Clodronate liposomes were used to investigate the fate of migrated and residential microglia cells. Pathologic angiogenesis was investigated in laser-induced choroidal neovascularization (CNV) after unshielded and shielded irradiation.
Flow cytometry revealed average transformation rates of 78.2% in unshielded and 64.1% in shielded group. Four weeks after transplantation, perfused flat mounts were virtually free of extravasal GFP+ cells in both groups, whereas 4 months after irradiation, cluster cell infiltrations, preferentially in the peripheral retina, became apparent exclusively in the unshielded group. Cell morphology ranged from oval, to a few extensions, to dendritiform with long-branched extensions. Clodronate treatment resulted in a reduction of GFP+ cells in the retinal tissue when applied 3 months after unshielded irradiation. Although GFP+ cells accumulated in the choroidal scar after laser treatment, in both the shielded and unshielded groups, GFP+ cells in the overlying retina were restricted to the unshielded group.
Approximately 3 months after lethal full-body irradiation including the eye, bone marrow-derived leukocytes exhibit a wound-healing reaction, and unlike physiological turnover, infiltrate the retina and form microglial cells.
小胶质细胞与免疫防御和修复有关。本研究评估了致死性骨髓耗竭和替代照射后视网膜疾病的进程，以及巨噬细胞和小胶质细胞的参与情况。
采用低电压放射单元对 C57BL/6 小鼠进行致死性照射。动物随机分为屏蔽组和非屏蔽组，随后接受 GFP+骨髓细胞（β-肌动蛋白启动子）移植。通过流式细胞术分析 GFP 转化率。在照射后 1 至 7 个月的各个时间点，用 GFP+细胞与巨噬细胞和树突状细胞标记物的共定位来检测视网膜中的 GFP+细胞。氯膦酸脂质体用于研究迁移和定居小胶质细胞的命运。在未屏蔽和屏蔽照射后的激光诱导脉络膜新生血管（CNV）中研究病理性血管生成。
流式细胞术显示未屏蔽组的平均转化率为 78.2%，屏蔽组为 64.1%。移植后 4 周，两组的灌注平面均无血管外 GFP+细胞，但照射后 4 个月，簇状细胞浸润，主要在周边视网膜，仅在未屏蔽组中明显。细胞形态从椭圆形、少数突起到具有长分支突起的树突状。氯膦酸盐处理在未屏蔽照射后 3 个月时可减少视网膜组织中的 GFP+细胞。尽管 GFP+细胞在激光处理后在脉络膜瘢痕中积聚，但在屏蔽和未屏蔽组中，覆盖视网膜上的 GFP+细胞仅限于未屏蔽组。
在包括眼睛在内的全身致死性照射后约 3 个月，骨髓来源的白细胞会发生伤口愈合反应，与生理更替不同，它们会浸润视网膜并形成小胶质细胞。
