The Study On The Correlation Between Postoperative Cognitive Dysfunction And Plasma CircRNA-089763 Expression In Elderly Patients Undergoing Non-cardiac Surgery

Objective:Postoperative cognitive dysfunction is a complication of neurological diseases in elderly patients.It has been found that circRNA is associated with the development of neurological diseases,but whether there is a relationship between POCD and circRNA is still unclear.Our research team has previously shown that the level of circRNA-089763 was significantly increased in plasma exosomes of patients with cognitive dysfunction after coronary artery bypass grafting.However,due to the limited source of patients undergoing coronary artery bypass grafting in previous experiments,and it was not verified in non-cardiac surgery either.Therefore,this study aims to expand the sample size to observe whether the level of circRNA-089763 in the plasma of elderly patients undergoing non-cardiac surgery has the same change,and to provide novel biomarkers of POCD and new clues to elucidate the underlying mechanisms.Methods:A prospective cohort study was conducted to random select elderly patients undergoing elective non-cardiac surgery from January2018 to October 2018 in our hospital,maintaining effective blood circulation and appropriate anesthesia depth during the operation.Cognitive function scales included Mini-mental State Examination(MMSE),Color Trail Test(CTT),Digital Span Test(DST),Clock Drawing Test(CDT)and Verbal Fluency Test(VFT)were completed on the day before operation and third day after operation,respectively.At the same time,20 healthy volunteers were screened as the control group for twice assessments of the above three-day interval.Then patients were divided into POCD group and non-PCOD group accroding to Z-score method.The basic information,surgical-related situation,VAS scores after operation and cognitive function scale scores of two groups were recorded and compared.Meanwhile,peripheral venous blood was collected on the day before surgery and third day after surgery,respectively.Then total RNA was extracted from plasma,and subsequently was reverse transcribed into cDNA using random primer.The circRNA was amplified by quantitative real-time polymerase chain reaction(qRT-PCR).Finally,the expression level of target genes were calculated by delta-delta Ct method using?-actin as internal reference,and differences in the expression level of circRNA-089763 between POCD group and NPOCD group were analyzed.And the correlation between the occurrence of POCD and the relative expression level of plasma circRNA-089763 was analyzed.Results:1.This study eventually included 72elderly surgical patients,including 26 orthopaedic patients,23 thoracic patients and 23 gastrointestinal patients.22 patients was diagnosed with postoperative cognitive dysfunction,and the overall incidence was 30.56%.The age of patients in the POCD group was older than that in the NPOCD group(t=5.971,P<0.05),and the incidence increased with age(?~2=23.137,P<0.05).The number of education years in the POCD group was shorter than that in the NPOCD group(t=2.449,P<0.05).The ASA grade in the POCD group was higher than that in the NPOCD group(?~2=14.726,P<0.05).There was no significant difference in gender,weight,height and BMI between the two groups(P>0.05).2.Intraoperative blood loss in POCD group was higher than that in NPOCD group,and the difference was statistically significant(t=3.196,P<0.05).There was no significant difference in anesthesia time,operation time and intraoperative fluid volume between the two groups(P>0.05).3.VAS scores of patients in POCD group were higher at third day after surgery than those in NPOCD group(t=10.45,P<0.05).There was no significant difference in the utilization rate of PCIA between the two groups(?~2=0.037,P>0.05).4.Compared with the day before surgery,in POCD group,MMSE,DST,CDT and VFT scores were decreased and CTT scores were increased on third day after surgery(P<0.05);in the NPOCD group,MMSE,DST and CDT scores decreased and CTT scores increased on three days after surgery(P<0.05),while the difference in VFT scale scores was not statistically significant(P>0.05).Compared with the NPOCD group on third day after surgery,MMSE,DST,CDT and VFT scores in the POCD group were significantly decreased,while CTT scores were significantly increased(P<0.05).There was no significant difference in preoperative scores of cognitive function scales between two groups(P>0.05).5.In each groups,65 patients with plasma samples met the requirements(260/280 optical density value>1.80,total RNA content?1000ng).There was no significant difference in OD and RNA concentrations between the two groups(P>0.05).6.The relative expression level of circRNA-089763 in POCD group was 2.41 times higher than that in NPOCD group on three days after surgery,and the difference was statistically significant(t=4.711,P<0.05).There was no statistical difference in the relative content of circRNA-089763 between two groups on the day before surgery(P>0.05).7.The relative expression level of circRNA-089763 at postoperative 3d was positively correlated with the occurrence of POCD(r=0.662,P<0.05),but not correlation at preoperative 1d(r=0.195,P>0.05).The relative expression level of circRNA-089763 on the third day after surgery was positively correlated with the sum of the Z scores of the nerve scales in the POCD group(r=0.752,P<0.05).Conclusion:1.The occurrence of POCD in elderly non-cardiac surgery patients is related to age,years of education,ASA classification,intraoperative blood loss and postoperative pain.2.The relative expression level of circRNA-089763 in plasma at third day after surgery was positively correlated with the occurrence of POCD in elderly patients undergoing non-cardiac surgery.