The Intervention Mechanism Of Remote Ischemic Postconditioning On The Inflammatory Markers Of Neutrophils After Acute Cerebral Infarction

Objective:The study was aimed at exploring the role of neutrophil in peripheral blood of acute ischemic stroke patients by evaluating temporal alterations of cell counts,NLR,the proportion of N2 phenotype and the expression of neutrophil surface markers including CD11b,CD 16 and CD66.The above indexes were also measured in patients under remote ischemic postconditioning to figure out whether the neuroprotective effect of remote ischemic postconditioning can be achieved by changing these neutrophil related indicators.Method:According to the inclusion criteria,fifty-four patients with acute ischemic stroke who were hospitalized in the Department of Neurology,The First Hospital of Jilin University and within 72 hours of onset were enrolled in our study from August to December 2019,and twelve adults who matched the age,gender and other risk factors of stroke were included in during the same period.They were divided into the conventional treatment group and the remote ischemic postconditioning(intermittent arm ischaemia through five cycles of 5-min inflation and 5-min deflation of a blood-pressure cuff)-RIPostC group based on their own will.Finally,there were 40 patients in the conventional treatment group and 14 in the RIPostC group.Baseline NIHSS scores were evaluated,neutrophil count(NE#),lymphocyte count(LY#)and neutrophil to lymphocyte ratio(NLR)were recorded on the first day and the seventh day of enrollment.Fasting peripheral blood samples of patients in RIPostC group were collected before treatment,1 day after treatment and 7 days after treatment.Blood samples of routine treatment group were collected at the same time point Blood samples of control group were only collected on the day of treatment.Neutrophils were isolated within 2 hours,stained with fluorescence coupled antibodies and assessed by flow cytometry measuring surface expression of CD11b,CD 16 and CD66,and mean fluorescence intensity(MFI)of each fluorescent dye was recorded.CD206 positive cells as N2 phenotype were gated and the proportion was caculated.Flowjo V10 was used for data analysis Flowjo V10 software is used for Flow Cytometry analysis,SPSS 25 and Prism 8 are used for data analysis and chart makingResult:(1)NE#and NLR of patients in conventional treatment group increased significantly on the first day(P<0.05)and decreased to normal on the seventh day compared with the control group(P>0.05).CD 16 MFI increased significantly on the first three days {P<0.05),and decreased to normal on the seventh day(P>0.05).CD66 MFI was normal 1-3 days after enrolled and decreased significantly 7 days later(P<0.005),while the proportion of N2 phenotype was opposite,normal 1-3 days after admission and increased significantly 7 days later(P<0.005).There was no significant change in LY#and CDllb MFI between this two groups neither did their trend(P>0.05).Multivariate regression analysis showed that NIHSS score had a positive correlation with NLR and CD16 MFI(R2=0.424,P=0.016),with standardized coefficients of 0.421 and 0.671,P values of 0.048 and 0.006,respectively.CD16 MFI had a greater impact on NIHSS score.(2)Compared with the routine treatment group,there was no significant difference in NE#,LY#,NLR,CD11b MFI,CD 16 MFI and N2 phenotype in RIPostC group(P>0.05).CD66 MFI of 7 days after RIPostC was significantly higher than that of the conventional treatment group at the same time point(P<0.005)Conclusion:(1)The count of neutrophil and the expression of inflammatory markers can be used to evaluate the degree and intensity of peripheral nonspecific inflammatory response in patients with acute ischemic stroke.(2)The early increase of NLR and CD 16 expression indicates that the peripheral immune response of patients is strong and the neurological deficit is serious,CD 16 expression is of a better index than NLR(3)The significant down-regulation of CD66 in the late stage wheras the increase of the proportion of N2 phenotype indicates that the peripheral non-specific inflammatory response is decreased and the inflammatory dissipation is active(4)The patients treated with RIPostC for one week within three days after onset failed to show a significant change in NE#,LY#,NLR,CD11b,CD16 and the proportion of N2 phenotype which indicates that RIPostC couldn’t exert its neuroprotective effect by affecting these indexes(5)CD66 as an indicator of neutrophil activation and phagocytosis whose upregulation may be related to the priming of neutrophil.