Effect of microglia inhibitor Pexidartinib on reconsolidation of remote contextual fear memory in mice
10.7683/xxyxyxb.2023.12.002
- VernacularTitle:小胶质细胞抑制剂Pexidartinib对小鼠遥远场景性恐惧记忆再巩固的影响
- Author:
Laifa WANG
1
;
Xueqin WANG
;
Ling DENG
;
Hui ZHANG
;
Yanhui CUI
Author Information
1. 长沙医学院神经科学与行为学研究中心,湖南 长沙 410219
- Keywords:
microglia;
Pexidartinib;
remote contextual fear;
memory reconsolidation;
phosphorylated bromodomain-con-taining protein 4;
gasdermin D;
mixed lineage kinase domain-like protein
- From:
Journal of Xinxiang Medical College
2023;40(12):1107-1113
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effect of microglia inhibitor Pexidartinib on reconsolidation of remote contextual fear memory in mice.Methods Twelve healthy C57BL/6 male mice were randomly divided into experimental group and control group,with 6 mice in each group.The mice in the two groups underwent contextual fear conditioning training in the contextual fear response box to establish the contextual fear models,and the freezing time of mice after each footshock was recorded.After 7 days,the mice in the experimental group were fed with food containing Pexidartinib formulation PLX3397,while the mice in the control group were fed with regular food until the end of behavioral experiment.On the 16th day after contextual fear conditioning training,the mice were put back into the contextual fear box for recalling the fear memory without any stimulation.The mice were taken out after 5 minutes of free exploration,and the freezing time of mice during this period was recorded.At 24 h after the fear memory was recalled,the mice were again placed in the contextual fear box,allowing them to explore freely for 3 minutes,and the freezing time of mice during this period was recorded;the fear response of mice was indicated by the percentage of freezing time.After the behavioral experiment,the mice were anesthetized by intraperitoneal injection of pentobarbital sodium,and three mice from the two groups were taken and rapidly opened the chest to expose their hearts,the perfusion needle was inserted into the left ventricle from the tip of heart and then was perfuse with 40 g·L-1 paraformaldehyde(pH=7.4)which precooled at 4 ℃ until the involuntary convulsion disappeared and the body limbs of mice were stiff.The brain tissue of mice was taken and fixed with paraformaldehyde solution,and then placed in sucrose solution for dehydration.The brain tissue of mice was coated with tissue embedding agent.The number of microglial cells in the hippocampus of mice in the two groups was detected by immunohistochemistry.The remaining mice in the two groups were taken and quickly decapitated to obtain brain tissues,and the hippocampus tissues of two sides were separated on ice.The expressions of phosphorylated bromodomain-containing protein 4(pBRD4),gasdermin D(GSDMD)and mixed lineage kinase domain-like protein(MLKL)in the hippocampus of mice were detected by Western blot.Results In the stage of contextual fear conditioning training,the percentage of freezing time of mice in two groups increased with the increase of the number of footshock(P＜0.05),but there was no significant difference in the percentage of freezing time of mice after the first,second,third,fourth and fifth footshock between the two groups(P＞0.05).There was no significant difference in the percentage of freezing time of mice between the two groups during recall period(P＞0.05).The percentage of freezing time of mice in the experimental group was significantly lower than that in the control group at the phase of memory test(P＜0.05).The number of microglia in CA1,CA3 and DG regions of hippocampus of mice in the experimental group was significantly lower than that in the control group(P＜0.05).The relative expressions of pBRD4,GSDMD and MLKL in hippocampus of mice in the experimental group were significantly lower than those in the control group(P＜0.05).Conclusion Microglia inhibitor Pexidartinib can injury the reconsolidation of remote contextual fear memory,which may be related to its inhibition of microglial cell activation and the down-regulation of the expressions of pBRD4,GSDMD and MLKL.
