Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, USA; Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, USA.
Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, USA.
Neurobiol Dis. 2019 Apr;124:544-554. doi: 10.1016/j.nbd.2018.12.018. Epub 2018 Dec 25.
Previous work has shown that non-invasive optical measurement of low cerebral blood flow (CBF) is an acute biomarker of poor long-term cognitive outcome after repetitive mild traumatic brain injury (rmTBI). Herein, we explore the relationship between acute cerebral blood flow and underlying neuroinflammation. Specifically, because neuroinflammation is a driver of secondary injury after TBI, we hypothesized that both glial activation and inflammatory signaling are associated with acute CBF and, by extension, with long-term cognitive outcome after rmTBI. To test this hypothesis, cortical CBF was non-invasively measured in anesthetized mice 4 h after 3 repetitive closed head injuries spaced once-daily, at which time brains were collected. Right hemispheres were fixed for immunohistochemical staining for glial activation markers Iba1 and GFAP while left hemispheres were used to quantify Iba1 and GFAP expression via Western blot as well as 32 cytokines and 21 phospho-proteins in the MAPK, PI3K/Akt, and NF-κB pathways using a Luminex multiplexed immunoassay. N = 8/7 injured/sham C57/black-6 adult male mice were studied. Within the injured group, CBF inversely correlated with Iba1 expression (R = -0.86, p < .01). Further, partial least squares regression analysis revealed significant correlations between CBF and expression of multiple pro-inflammatory cytokines, including RANTES and IL-17. Finally, within the injured group, phosphorylation of specific signals in the MAPK and NF-κB intracellular signaling pathways (e.g., p38 MAPK and NF-κB) were significantly positively correlated with Iba1. In total, our data indicate that acute cerebral blood flow after rmTBI is a biomarker of underlying neuroinflammatory pathology.
先前的工作表明，对低脑血流（CBF）的非侵入性光学测量是重复轻度创伤性脑损伤（rmTBI）后长期认知预后不良的急性生物标志物。在此，我们探讨了急性脑血流与潜在神经炎症之间的关系。具体来说，由于神经炎症是 TBI 后继发性损伤的驱动因素，我们假设神经胶质细胞激活和炎症信号都与急性 CBF 相关，并且可以扩展到 rmTBI 后的长期认知结果。为了验证这一假设，在重复 3 次闭合性颅脑损伤后 4 小时，对麻醉小鼠进行了皮质 CBF 的非侵入性测量，此时收集了大脑。对右半脑进行了小胶质细胞激活标志物 Iba1 和 GFAP 的免疫组织化学染色固定，而对左半脑则通过 Western blot 来量化 Iba1 和 GFAP 的表达，同时使用 Luminex 多重免疫分析测定 MAPK、PI3K/Akt 和 NF-κB 通路中的 32 种细胞因子和 21 种磷酸化蛋白。研究了 8/7 只受伤/假手术 C57/黑 6 成年雄性小鼠。在受伤组中，CBF 与 Iba1 表达呈负相关（R = -0.86，p <.01）。此外，偏最小二乘回归分析显示，CBF 与多种促炎细胞因子的表达之间存在显著相关性，包括 RANTES 和 IL-17。最后，在受伤组中，MAPK 和 NF-κB 细胞内信号转导通路中的特定信号（例如 p38 MAPK 和 NF-κB）的磷酸化与 Iba1 显著正相关。总之，我们的数据表明，rmTBI 后的急性脑血流是潜在神经炎症病理的生物标志物。
