River Hill High School, Columbia, MD 21029, USA; Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
J Control Release. 2017 Oct 10;263:192-199. doi: 10.1016/j.jconrel.2017.03.032. Epub 2017 Mar 21.
Traumatic brain injury (TBI) is a serious public health problem, often with devastating consequences for patients and their families. Affordable and timely therapies can have a substantial impact on outcomes in severe TBI. Despite the common use of sedatives and anesthetics in the acute phase of TBI management, their effect on glial cells is not well understood. We investigated the effect of a commonly used sedative, pentobarbital, on glial cells and their uptake of nanoparticles. First, we studied how pentobarbital affects BV2 mouse microglial cells in culture. The cell morphology was imaged by confocal microscopy and analyzed. Our results suggest that microglia change to a more swollen, 'activated' shape with pentobarbital (cell area increased by approximately 20%, p<0.001). Such glial activation may have negative implications for the ability of the injured brain to clear edema. Second, we investigated how pentobarbital treatment affected nanoparticle uptake. BV-2 mouse microglial cells in the presence and absence of pentobarbital were treated with fluorescently-labeled, hydroxyl-functionalized poly(amidoamine) dendrimer nanoparticles (Dendrimer-Cy5). We demonstrated that the presence of pentobarbital increased the dendrimer nanoparticle uptake significantly (~2-fold both 2 and 6h following treatment). This semi-quantitative fluorescence assessment was broadly consistent among confocal image analysis, flow cytometry, and fluorescence quantification of cell-extracted dendrimer-Cy5. Although anesthetics appear to activate microglia, the increased uptake of dendrimer nanoparticles in their presence can be exploited to deliver drug-loaded nanoparticles directly to microglia after TBI. These drugs could restore glial and glymphatic function, enabling efficient drainage of waste and fluid from the brain and effectively improving recovery after TBI. A key future direction is to validate these findings in TBI models.
创伤性脑损伤 (TBI) 是一个严重的公共卫生问题，常常给患者及其家庭带来毁灭性的后果。负担得起且及时的治疗方法可以对严重 TBI 的结果产生重大影响。尽管在 TBI 管理的急性期经常使用镇静剂和麻醉剂，但它们对神经胶质细胞的影响尚不清楚。我们研究了一种常用镇静剂戊巴比妥对神经胶质细胞及其对纳米颗粒摄取的影响。首先，我们研究了戊巴比妥如何影响培养的 BV2 小鼠小胶质细胞。通过共聚焦显微镜对细胞形态进行成像和分析。我们的结果表明，戊巴比妥使小胶质细胞转变为更肿胀的“激活”形态（细胞面积增加约 20%，p<0.001）。这种神经胶质细胞激活可能对受伤大脑清除水肿的能力产生负面影响。其次，我们研究了戊巴比妥处理如何影响纳米颗粒摄取。在存在和不存在戊巴比妥的情况下，用荧光标记的、羟基功能化的聚（酰胺-胺）树枝状大分子纳米颗粒（Dendrimer-Cy5）处理 BV-2 小鼠小胶质细胞。我们证明，戊巴比妥的存在显著增加了树枝状大分子纳米颗粒的摄取（处理后 2 和 6 小时均增加约 2 倍）。这种半定量荧光评估与共聚焦图像分析、流式细胞术以及从细胞中提取的 Dendrimer-Cy5 的荧光定量在很大程度上是一致的。尽管麻醉剂似乎激活了小胶质细胞，但在它们存在的情况下增加了树枝状大分子纳米颗粒的摄取，可以在 TBI 后将载药纳米颗粒直接递送至小胶质细胞。这些药物可以恢复神经胶质和糖液功能，有效地从大脑中排出废物和液体，从而有效地改善 TBI 后的恢复。一个关键的未来方向是在 TBI 模型中验证这些发现。
