The Analysis Of The Brain Protection Of Methylation Of Lipoxin A₄ To The Aged Cognitive Impairment Rats

Objective:Cognitive impairment model was established in aged SD rats,to observe the effect of LXA₄ ME on learning and memory ability in rats,to explore the mechanism of cognitive impairment in aged rats leaded by anesthesia of LXA₄ ME and identify Whether the improvement of cognitive impairment induced by LXA4 ME is related to the relief of oxidative stress and autophagy.Methods:Forty-four healthy male SD rats were randomly divided into four groups:control group;LXA₄ ME 100ng group?simple administration group?;3%SEV+splenectomy group?model group?;3%SEV+splenectomy+LXA₄ ME100ng group?treatment group?.Two weeks before surgery,stereotaxic lateral ventricle catheterwere given to the rats.5 days before surgery,behavioral test?Place navigation test?was given to the rats to evaluate the ability of learning of the rats.The day of surgery,control group and model group were given saline 5?l/d by a micro syringe?up to 3 days?;Simple administration group and treatment group were given LXA₄ ME 100ng/d by a micro syringe?up to 3 days?.Evaluate the cognitive of each group by water maze test.Then killed the rats.Subsequently,HE and Nissl staining were performed to observe the morphological changes of neurons in the hippocampal CA1 region.Flow cytometry was used to analyze the changes of ROS levels.The expression of DJ-1 protein was evaluated by immunohistochemistry.The expressions of DJ-1,JNK,P-JNK and Beclin1were detected by Western blot.Result:1 Determination of behavioral cognitive function:1.1 Preoperative five days,the escape latency results:The escape latency of rats of each group was no significant difference?P>0.05?.After 5 days of repeated training,the platform could be quickly and accurately located of the rats.1.2 Percentage of time spent in target quadrant and the number of crossing platforms after 3 days postoperative results:There was no significant difference in target quadrant and times of crossing platforms between the control group and the simple administration group?P>0.05?.Compared with the control group,the target quadrant residence time was shortened of the model group and the treatment group,and the number of crossing platforms was reduced?P<0.05?.Compared with the model group,the target quadrant residence time of the treatment group was prolonged?P<0.05?,and the number of crossing platforms was increased?P<0.05?.2 Morphological observation:The HE and Nissl staining results of paraffin sections showed that the neurons in the hippocampal CA1 area of the control group and the simple administration group were intact and closely arranged.The neurons in the model group were irregular in shape and the neurons were severely damaged.The treatment group was less damaged than the model group.3 Immunohistochemistry results:3 days after operation,there was no significant difference between the simple administration group and the control group?P>0.05?.Compared with the control group,the expression of DJ-1 protein was increased in the model group and the treatment group?P<0.05?.Compared with the model group,treatment The expression of DJ-1 protein was significantly increased?P<0.01?.4 Detection of intracellular ROS levels results show:3 days after operation,there was no significant difference in the intracellular ROS level between the control group and the single administration group?P>0.05?.Compared with the control group,the level of ROS was increased in the hippocampus of the model group and the treatment group?P<0.01?,the ROS level was lower in the treatment group than in the model group?P<0.05?.5 Western blot results:There was no significant difference in JNK between the groups?P>0.05?.There were no significant differences in DJ-1,P-JNK and Beclin1 between the control group and the simple administration group?P>0.05?.Compared with the control group,the expression of DJ-1,P-JNK and Beclin1 in the model group and the treatment group increased?P<0.05?.Compared with the model group,the expression of DJ-1 increased in the treatment group?P<0.05?,P-JNK,Beclin1 expression decreased?P<0.05?.Conclusion:LXA₄ ME can improve the symptoms of cognitive impairment of rats and alleviate the oxidative stress level and excessive autophagy in hippocampal CA1 neurons.The effect may be through activation of DJ-1/JNK/Beclin1 signal pathway.