Macrophages and granulocytes play an important role in various injuries and post-traumatic repair. Due to the limited number of neutrophils in the brain, their role in traumatic brain injury has rarely been mentioned. Here, neutrophils were found to take over the role of macrophages after brain injury in the absence of macrophages. Neutrophils have the characteristics of long residence time and number advantage to actively remove the apoptotic debris. The number of neutrophils recruited was effectively reduced by inhibiting IL-1β. Interestingly, neutrophils migrated regularly and rapidly to the wound during the early stages of brain injury through three paths. They first infiltrated the wound mainly through blood circulation around the eyes, then became unscrupulous and began to move directly across the brain. In addition, MMP9 and MMP13 were found to be related to the migration of neutrophils, and inhibition of MMP could significantly inhibit the number and speed of neutrophils’ migration. Our study showed that neutrophils rely on MMP9 and MMP13 for a rapid and orderly response to brain injury to maintain central nervous system stability in the absence or decrease of macrophages.

巨噬细胞和粒细胞在各种损伤和创伤后修复中发挥重要作用。由于大脑中的中性粒细胞数量有限，它们在创伤性脑损伤中的作用很少被提及。在这里，发现中性粒细胞在没有巨噬细胞的情况下在脑损伤后接管巨噬细胞的作用。中性粒细胞具有停留时间长、数量优势等特点，能主动清除凋亡碎片。通过抑制 IL-1β，可以有效减少募集的中性粒细胞数量。有趣的是，在脑损伤的早期阶段，中性粒细胞通过三种途径有规律地快速迁移到伤口。他们首先主要通过眼睛周围的血液循环渗入伤口，然后变得肆无忌惮，开始直接穿过大脑。此外，发现MMP9和MMP13与中性粒细胞的迁移有关，抑制MMP可显着抑制中性粒细胞迁移的数量和速度。我们的研究表明，中性粒细胞依赖 MMP9 和 MMP13 对脑损伤做出快速有序的反应，以在巨噬细胞缺失或减少的情况下维持中枢神经系统的稳定性。