Department of Anesthesiology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1 (Bld. 505), 55131, Mainz, Germany.
Institute for Immunology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany.
J Neuroinflammation. 2019 Aug 5;16(1):163. doi: 10.1186/s12974-019-1550-0.
Traumatic brain injury (TBI) is a major cause of death and disability. T cells were shown to infiltrate the brain during the first days after injury and to exacerbate tissue damage. The objective of this study was to investigate the hitherto unresolved role of immunosuppressive, regulatory T cells (Tregs) in experimental TBI.
"Depletion of regulatory T cell" (DEREG) and wild type (WT) C57Bl/6 mice, treated with diphtheria toxin (DTx) to deplete Tregs or to serve as control, were subjected to the controlled cortical impact (CCI) model of TBI. Neurological and motor deficits were examined until 5 days post-injury (dpi). At the 5 dpi endpoint, (immuno-) histological, protein, and gene expression analyses were carried out to evaluate the consequences of Tregs depletion. Comparison of parametric or non-parametric data between two groups was done using Student's t test or the Mann-Whitney U test. For multiple comparisons, p values were calculated by one-way or two-way ANOVA followed by specific post hoc tests.
The overall neurological outcome at 5 dpi was not different between DEREG and WT mice but more severe motor deficits occurred transiently at 1 dpi in DEREG mice. DEREG and WT mice did not differ in the extent of brain damage, blood-brain barrier (BBB) disruption, or neuronal excitotoxicity, as examined by lesion volumetry, immunoglobulin G (IgG) extravasation, or calpain-generated αII-spectrin breakdown products (SBDPs), respectively. In contrast, increased protein levels of glial fibrillary acidic protein (GFAP) and GFAP+ astrocytes in the ipsilesional brain tissue indicated exaggerated reactive astrogliosis in DEREG mice. T cell counts following anti-CD3 immunohistochemistry and gene expression analyses of Cd247 (CD3 subunit zeta) and Cd8a (CD8a) further indicated an increased number of T cells infiltrating the brain injury sites of DEREG mice compared to WT. These changes coincided with increased gene expression of pro-inflammatory interferon-γ (Ifng) in DEREG mice compared to WT in the injured brain.
The results show that the depletion of Tregs attenuates T cell brain infiltration, reactive astrogliosis, interferon-γ gene expression, and transiently motor deficits in murine acute traumatic brain injury.
创伤性脑损伤（TBI）是死亡和残疾的主要原因。研究表明，T 细胞在损伤后最初几天内浸润大脑，并加重组织损伤。本研究的目的是探讨调节性 T 细胞（Tregs）在实验性 TBI 中的作用。
用白喉毒素（DTx）处理“调节性 T 细胞耗竭”（DEREG）和野生型（WT）C57Bl/6 小鼠以耗竭 Tregs 或作为对照，然后进行皮质撞击（CCI）模型的 TBI。神经学和运动缺陷检查持续到损伤后 5 天（dpi）。在 5 dpi 终点，进行（免疫）组织学、蛋白质和基因表达分析，以评估 Tregs 耗竭的后果。两组间参数或非参数数据的比较采用 Student's t 检验或 Mann-Whitney U 检验。对于多重比较，通过单向或双向 ANOVA 计算 p 值，然后进行特定的事后检验。
5 dpi 时，DEREG 和 WT 小鼠的总体神经预后无差异，但 DEREG 小鼠在 1 dpi 时出现更严重的运动缺陷。用损伤体积、免疫球蛋白 G（IgG）外渗或钙蛋白酶生成的 αII- spectrin 断裂产物（SBDPs）分别检测脑损伤程度、血脑屏障（BBB）破坏或神经元兴奋性毒性时，DEREG 和 WT 小鼠之间无差异。相反，同侧脑组织中胶质纤维酸性蛋白（GFAP）和 GFAP+星形胶质细胞的蛋白水平升高表明 DEREG 小鼠的反应性星形胶质细胞增生过度。抗 CD3 免疫组化和 Cd247（CD3 亚基 ζ）和 Cd8a（CD8a）的基因表达分析后的 T 细胞计数进一步表明，与 WT 相比，DEREG 小鼠的 T 细胞浸润脑损伤部位的数量增加。这些变化与 DEREG 小鼠损伤脑内促炎干扰素-γ（Ifng）的基因表达增加相一致。
结果表明，Tregs 的耗竭可减轻小鼠急性创伤性脑损伤中的 T 细胞脑浸润、反应性星形胶质细胞增生、干扰素-γ基因表达和短暂的运动缺陷。
