Changed Serum Bdnf,Inflammatory Factor Levels And Their Correlations With Sleep And Cognitive Function In Patients With Chronic Insomnia

【Objective】To investigate whether serum BDNF,TNF-α,IL-1β and IL-6 levels change in patients with chronic insomnia,and their correlation with sleep structure and cognitive function.【Methods】Forty-one patients with chronic insomnia disorder(CID)attending the outpatient and inpatient departments of the Department of Neurology at the First Affiliated Hospital of South China University from August 2019 to February 2021 were collected,and 22 normal sleepers matched for gender,age,and educational level at the same time period were collected as controls.General information was collected on all subjects,including:gender,age,education level,and occupation.The Pittsburgh Sleep Quality Index(PSQI)was used to assess the subjective insomnia and sleep quality of the subjects.Polysomnography(PSG)was used to assess the objective sleep status of the subjects,and the main monitoring parameters included:total sleep time(TST),sleep onset latency(SOL),wake after sleep onset(WASO),arousal(Arl),sleep efficiency(SE),percentage of total sleep time accounted for by none rapid eye movement(N1,N2,N3)and rapid eye movement(REM)sleep periods(N1%,N2%,N3%,REM%).Montreal Cognitive Assessment(Mo CA)scale was used to assess the subjects’ s cognitive function.Self-rating Anxiety Scale(SAS)was used to assess the anxiety level of the subjects.Self-rating Depressive Scale(SDS)was used to assess the depression level of the subjects.Fasting venous blood was drawn from 8:00-9:00 a.m.and serum levels of BDNF,TNF-α,IL-6 and IL-1β were tested by enzyme-linked immunosorbent assay(ELISA).Finally,the study data were analyzed and processed using statistical methods.【Results】1.General information: there were no significant differences in gender,age and education between the CID group and the control group(P > 0.05).2.Sleep quality: Compared with the control group,the PSQI score of the CID group was higher,and the difference was significant(P < 0.01);changes in the main PSG parameters: TST decreased,SOL prolonged,SE decreased,WASO increased,N1% increased and N3% decreased in patients with chronic insomnia,and the difference was statistically significant(P < 0.05).3.Cognitive function: the total Mo CA score and the scores of visuospatial and executive function,language and delayed recall factor in the CID group were lower than those in controls,and the differences were statistically significant(P < 0.05).4.Serum BDNF,TNF-α,IL-1β and IL-6 levels: serum BDNF levels were significantly lower in the CID group(t=-6.350,P<0.01),while inflammatory factors TNF-α,IL-6 and IL-1β were significantly higher(Z=-2.228,P<0.05;Z=-2.984,P<0.05;Z=-2.465,P < 0.05),and the differences were statistically significant.5.Correlation of serum marker levels with sleep structure and cognitive function.(1)sleep quality: serum TNF-α was negatively correlated with PSQI score in the CID group(r=-0.340,P=0.034).Serum BDNF,IL-6,and IL-1β did not correlate with PSQI scores and major PSG parameters.(2)cognitive function: BDNF was positively correlated with total Mo CA score,visuospatial/executive function and attention score in the CID group(r=0.431,P=0.006;r=-0.430,P=0.006;r=0.353,P=0.028).TNF-α was negatively correlated with delayed recall score(r=-0.347,P=0.030);IL-6 was negatively correlated with the total Mo CA score(r=-0.371,P=0.020);IL-1β was negatively correlated with the total Mo CA score and delayed recall(r=-0.496,P=0.001;r=-0.475,P=0.002).【Conclusion】Serum BDNF levels were significantly lower in patients with CID,while the levels of inflammatory factors TNF-α,IL-6,and IL-1β were increased,changes in serum BDNF and inflammatory factors in CID patients correlated with the severity of insomnia and cognitive impairment.