| Background and 0bjective: Increasing studies have suggested that serum micro RNAs play important roles in diseases diagnosis and therapy.Our previous study showed that the level of mi R-221-3p in CSF and serum of patients with major depressive disorder was significantly higher than that in normal subjects,indicating the value of mi R-221-3p in the diagnosis of major depressive disease.However,whether the serum level of mi R-221-3p is helpful to the diagnosis of depressive mood is still unknown.Therefore,in this study,we firstly examined the relative expression of serum mi R-221-3p in periopetative patients with different degrees of depressive mood.Secondly,we tested the absolute level of serum mi R-221-3p in normal individuals and the patients with depressive mood through preparing the standards of mi R-221-3p.Finally,we analyzed the correlation between the serum level of mi R-221-3p and the scores of PHQ-9.We hope to further clarify the value and significance of serum mi R-221-3p in the diagnosis of depressive mood.Methods: 1.Serum samples were collected from enrolled perioperative patients,subsequently they were divided into normal group,mild depressive mood group and moderate to severe depressive mood group according to their PHQ-9 scores. 2.The relative level of serum mi R-221-3p was measured by real-time fluorescent quantitative polymerase chain reaction.3.Serum total RNA was extracted and then transcribed into c DNA with mi R-221-3p specific primers.PCR was performed to obtain DNA fragment with mi R-221-3p included,which was inserted into pc DNA3.1 plasmid.The recombinant plasmid(pc DNA3.1-mi R-221-3p)was proved to be correctly constructed through bing sequenced.Gene fragment containing T7 promoter and mi R-221-3p was obtained by PCR from pc DNA3.1-mi R-221-3p,and RNA standard materials were harvested by in vitro RNA transcription and purification,the concentration(copies/?g RNA)of standard materials of mi R-221-3p was finally calculated.4.The standard materials of mi R-221-3p were gradually diluted,and the threshold cycle(Ct)of these diluted standard materials were measured by real-time fluorescent quantitative polymerase chain reaction.Standard curve was plotted according to the Ct and concentration of each standard material.5.The absolute content of serum mi R-221-3p was calculated according to the standard curve,and then the correlation between the level of serum mi R-221-3p and the scores of PHQ-9 was analyzed.Results: 1.There were no significant difference in age,sex,operation time,anesthesia time,blood loss and the pain scores among the three groups(P>0.05).2.The relative level of serum mi R-221-3p in the patients with mild and more severe depression was significantly higher than that in normal group(P<0.05).The relative content of serum mi R-221-3p in patients with mild depression was 2.21 times higher than that in the normal group,and the relative content of serum mi R-221-3p in the patients with the moderate to severe depression was 3.66 times higher than that in the normal group.3.Recombinant plasmid of mi R-221-3p was constructed successfully,and the standard materials of mi R-221-3p were obtained by transcription in vitro and purification;the copies of the standard materials were 1.27*1012,the concentration was 8.39*1012 copies/?g RNA.4.The standard curve formula is as follows: Y = 3.49214E+12e-0.5871 X,R2=0.9999,the X stands for the threshold cycle,the Y stands for the absolute content(copies).5.The result of correlation between the absolute content of serum mi R-221-3p and PHQ-9 scores of patients with depressive mood showed that the depressive scores of patiens were greater than or equal to 6 points when the level of serum mi R-221-3p was higher than 1.7*107(copies/?g RNA).Conclusion: 1.The relative level of serum mi R-221-3p in perioperative patients with depressive mood is significantly higher than that in normal individuals. 2.When the concentration of serum mi R-221-3p is higher than 1.7*107 copies/?g RNA,it may be used as a biological marker of evaluating perioperative depressive mood. |
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