Levels Of Serum Thioredoxin System In Patients With Insomnia Disorder And Healthy Control: A Case-control Study

Objectives:To assess the level of serum cytosolic thioredoxin(Trx1) and thioredoxin reductase(TrxR2) along with mitochondrial Trx2 and TrxR2 in patients with insomnia disorder and to explore the relationship between insomnia disorder and oxidative stress.Methods:27 patients with insomnia disorder(ID) and 20 healthy controls(HC) were recruited in the study through the structured Diagnostic Interview for Sleep Patterns and Disorders, and DSM-5 diagnostic criteria about insomnia disorder. All subjects were non-smokers. Then investigated by questionaires including the General Situation Questionnaire, Flinders Fatigue Scale(FFS), Epworth Sleepiness Scale(ESS), State-Trait Anxiety Inventory(STAI), Beck Depression Inventory Revised(BDI-R), Glasgow Sleep Effort Scale(GSES), Ford Insomnia Response to Stress Test(FIRST), Pittsburgh Sleep Quality Index(PSQI), Insomnia Severity Index(ISI), as well assessed by overnight Polysomnography(PSG). At 7:30am to 8:30am the next morning,3ml blood of all the subjects were collected from vein of the left arm when limosis, then the serums were collected by centrifugal separation(4℃ 3000r/m). The serum Trx1, TrxR1, Trx2, TrxR2 were assayed by enzyme-linked immunesorbent assay(ELISA). Data were recorded and analyzed by SPSS 17.0 statistical software.Results:1. Compared with healthy controls, the degrees of fatigue, anxiety, depression, stress-induced insomnia in patients with ID were significantly different(P<0.05); ID patients showed more effort to control sleep and reported worsen sleep quality.(P<0.05).2. Serum TrxRl levels of patients with ID were significantly higher than the HC(P<0.000), while there was no significant difference in serum Trxl between ID patients and HC.3. Serum Trx2, TrxR2 levels of patients with ID were significantly higher than the HC(Z=4.260, P=0.000;t=3.332, P=0.002).4. Serum Trx1, TrxR1, Trx2, TrxR2 levels of patients with ID had no correlation with sex, age, the scores of FFS, ISI, GSES, FIRST, STAI, BDI-R and PSQI(P>0.05).5. Serum Trx2 levels of patients with ID were positively related to the percent of N1 sleep and REM sleep on PSG(r=0.399, P=0.039; r=0.433,P=0.024).6. There was no correlation between serum TrxR1, TrxR2 levels and PSG indices in patients with ID(P>0.05).Conclusions:1. Serum TrxR1, Trx2, TrxR2 levels of patients with ID were overexpression, indicating there is imbalance between oxidants and antioxidants, as well increased systemic oxidative stress, which activating cytoplasm TrxR1 increased and elevating the ability of mitochondria Trx system’s antioxidation as a compensatory effect. Oxidative stress appears to be associated with insomnia disorder.2. Serum Trx2 levels of patients with ID were positively related to the percent of N1 sleep and REM sleep on PSG, the mitochondrial Trx may take part in the pathophysiological process of insomnia disorder.