中性粒细胞在老年小鼠术后认知功能障碍中的作用研究

Effect of neutrophils on postoperative cognitive dysfunction in aged mice

目的检测中性粒细胞是否参与老年小鼠术后认知功能障碍的发生、发展过程,并探讨消除中性粒细胞改善认知功能的可能性。方法将C57BL/6J老年小鼠随机分为对照组(6只)和手术组(5只),手术组在异氟烷麻醉下制备胫骨骨折复位内固定术模型。使用流式细胞术检测术后第2天的外周血中性粒细胞百分比。采用相同方法另制备对照和手术模型小鼠,分为4组:对照组、粒细胞分化抗原1抗体(抗Gr1)组、手术组和抗Gr1+手术组,每组8只。从造模前1天开始,两组抗Gr1组使用Gr1抗体进行腹腔内注射(6 mg/kg,1次/d)治疗,连续给药4 d。通过进行新物体识别实验观察小鼠的识别记忆能力。结果术后第2天,与对照组相比,手术组外周循环中的中性粒细胞百分比显著升高(P<0.01)。抗Gr1抗体可以消除老年小鼠外周血中的中性粒细胞。对照组、抗Gr1+手术组小鼠探索新物体时间均显著长于旧物体(P<0.01,0.05),而手术组小鼠探索新旧物体时间的差异无统计学意义(P>0.05),同时,手术组对新旧物体的识别系数显著低于对照组(P<0.05)。结论中性粒细胞参与了老年小鼠术后认知功能障碍,抗中性粒细胞治疗可明显改善老年小鼠术后的认知功能。

Objective To determine whether neutrophils are involved in the occurrence and development of postoperative cognitive dysfunction in aged mice,and to explore the possibility of improving cognitive function by eliminating neutrophils.Methods C57BL/6J aged mice were randomly divided into 4 groups(n=8):control group,anti-granulocyte-differentiation antigen 1(anti-Gr1)group,operation group and anti-Gr1+operation group.The model of tibial fracture reduction and internal fixation was prepared under isoflurane anesthesia.Anti-Gr1 antibody was intraperitoneally injected(6 mg/kg,once a day)as a neutrophil eliminator for 4 d(starting from the day before modeling).The recognition and memory ability of mice was observed by conducting new object recognition experiments.Results Compared with the control group,neutrophils in the peripheral blood of aged mice in the operation group significantly increased on day 2 after surgery.The neutrophils in the anti-Gr1 group and anti-Gr1+operation group significantly decreased.The time of new object recognition was significantly longer than that of old objects in the control group and anti-Gr1+operation group(P<0.01,0.05).There was no significant difference in the time of new and old object recognition in the operation group(P>0.05).The coefficient of new and old object recognition in the operation group was significantly lower than that in the control group(P<0.05).Conclusion Anti-Gr1 antibody can reduce postoperative cognitive dysfunction in elderly mice by clearing neutrophils.Antineutrophil therapy significantly improved the cognitive function of aged mice after surgery.