人脑挫裂伤后早期小胶质细胞PD-L1的表达

PD-L1 expression in microglial cells early after contusion and laceration of human brain

目的探讨人脑挫裂伤后早期小胶质细胞程序性细胞死亡因子1配体（PD-L1）的表达变化。方法收集2013～2015年手术治疗的脑挫裂伤组织标本15例,其中伤后6h 5例,伤后12h 4例,伤后1 d 3例,伤后4 d 3例;另选择3例肿瘤全切术中切除颞极组织作为对照组。采用HE染色及免疫荧光染色分析炎症细胞浸润情况,以及小胶质细胞PD-L1的表达情况。结果 HE染色结果显示,与对照组脑组织相比,脑挫裂伤后6、12h未见到明显的炎症细胞浸润;随着损伤时间的延长,浸润的来自血液中的炎症细胞明显增加（P〈0.05）。免疫荧光染色结果显示,与对照组脑组织相比,脑挫裂伤后6h表达PD-L1的小胶质细胞阳性细胞数明显升高（P〈0.01）;随着损伤时间的延长,表达PD-L1的小胶质细胞阳性细胞数进一步升高（P〈0.05）。结论 PD-L1可能参与了人脑挫裂伤后的炎症反应。

Objective To explore the changes in programmed death-1 ligand（PD-L1） expression in microglia cells early after contusion and laceration of human brain.Methods Eighteen cerebral tissues specimens, of which 3 were normal cerebral tissues, 5, 4, 3 and 3 were contused and lacerated cerebral tissues 6 hours, 12 hours, 1 day and 4 days after the brain injury respectively, were fixed by perfusion of 4% paraformaldehyde. Frozen sections were made for H-E and immunofluoresent staining and then the number of infiltrating inflammatory cells and the expression of PD-L1 in the microglial cells were determined.Results The results of H-E staining showed that the number of infiltrating inflammatory cells in the contused and lacerated cerebral tissues 1 day after injury was significantly more than those in the normal cerebral tissues（P〈0.05）, and the number of infiltrating inflammatory cells significantly increased as the time increased after injury（P〈0.05）. The results of immunofluoresent staining that the number of PD-L1 positive microglial cells in the contused and lacerated cerebral tissues 6 hours after injury was significantly more than those in the normal cerebral tissues（P〈0.05）, and the number of PD-L1 positive microglial cells significantly increased as the time increased after injury（P〈0.05）.Conclusions It is suggested that PD-L1 may be involved in the inflammation after human cerebral contusion and laceration and the intervention of the PD-1/PD-L1 signaling pathway may be a new method to treat the human cerebral contusion and laceration.