静脉注射的荧光钠（SF）在脑胶质瘤和脑转移手术中的应用日益增多，以提高肿瘤切除率。目前认为，SF渗透到破坏血脑屏障（BBB）的脑区域，并在细胞外间隙积累，而不积累于肿瘤或健康细胞，从而能够标定肿瘤边缘以指导切除。通过评估一些进行SF引导手术的患者新鲜切除的脑胶质瘤和脑转移瘤的免疫环境，作者经常观察到荧光阳性细胞。因此，本研究的目的是确定SF是否在肿瘤微环境（TME）的细胞内积累，如果积累，积累在哪种类型的细胞内，并且外周血的白细胞是否也会观察到积累。将新鲜切除的肿瘤标本离散成单个细胞，并通过多参数流式细胞术进行分析。在体外处理SF后，通过多参数和成像流式细胞术以及共聚焦显微镜检测细胞摄取SF。体外和体内分析表明，SF在白细胞和肿瘤细胞内积累，但在不同的细胞子集中积累的程度变化较大。粒细胞系细胞表现出最高的荧光水平。体外摄取实验证实，SF的积累随时间增加。成像分析证实了该化合物在细胞内的内化。SF不仅仅是BBB损伤的标志物，其细胞内检测表明它是有选择地在细胞内积累。未来的努力应该深入研究其在不同TME细胞类型中的吸收机制。

Intravenous sodium fluorescein (SF) is increasingly used during surgery of gliomas and brain metastases to improve tumor resection. Currently, SF is believed to permeate the brain regions where the blood-brain barrier (BBB) is damaged and to accumulate in the extracellular space but not in tumor or healthy cells, making it possible to demarcate tumor margins to guide resection. By evaluating the immune contexture of a number of freshly resected gliomas and brain metastases from patients undergoing SF-guided surgery, the authors recurrently observed fluorescence-positive cells. Therefore, the aim of this study was to determine if SF accumulates inside the cells of the tumor microenvironment (TME), and if so, in which type of cells, and whether incorporation can also be observed in the leukocytes of peripheral blood.Freshly resected tumor specimens were dissociated to single cells and analyzed by multiparametric flow cytometry. Peripheral blood leukocytes, macrophages, and a glioma cell line were treated with SF in vitro, and their cell uptake was assessed by multiparametric and imaging flow cytometry and by confocal microscopy.The ex vivo and in vitro analyses revealed that SF accumulates intracellularly in leukocytes as well as in tumor cells, but with a high variability of incorporation in the different cell subsets analyzed. Myeloid cells showed the highest level of fluorescence. In vitro uptake experiments showed that SF accumulation increases over time. The imaging analyses confirmed the internalization of the compound inside the cells.SF is not just a marker of BBB damage, but its intracellular detection suggests that it selectively accumulates intracellularly. Future efforts should target the mechanisms of its differential uptake by the different TME cell types in depth.