ABSTRACT
Objective To investigate the adjustment effect of microRNA-155 on CD4+CD25+ regulative T cell (Treg) in peripheral blood of sepsis patients,and to elucidate the role of miR-155 in the pathogenesis of sepsis.Methods A retrospective study was corducted.60 sepsis patients (mild n =20,moderate n=20,and severe n =20)from emergency room or intensive care unit (ICU) of the Fourth Hospital of Jiangsu University were enrolled.20 healthy volunteers were enrolled as controls.Real-time fluorescent quantitation polymerase chain reaction (qRT-PCR) was used to detect the levels of miR-155 and Foxp3 mRNA expressions in peripheral blood.CD4+CD25+ Treg cells in peripheral blood were identified by flow cytometry.Peripheral interleukin-10 (IL-10) was measured by enzyme-linked immunosorbent assay (ELISA).Results The expressions of miR-155,Treg,Foxp3 mRNA and the level of IL-10were higher in the patients with sepsis than those in healthy control group [Treg:(2.89 ± 1.13)％ vs.(2.32 ± 0.91)％,t=10.540,P=0.002; miR-155:1.19 ±0.48 vs.0.80 ±0.33,t=8.605,P=0.006; Foxp3 mRNA:0.18 ±0.08 vs.0.13 ±0.03,t=6.862,P=0.008; IL-10 (ng/L):56.89 ± 17.28 vs.33.24 ± 11.93,t=12.742,P=0.001].These variables were elevated gradually with the elevation of acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ)score.The expressions of Treg,miR-155,Foxp3 mRNA and the level of IL-10 were (3.05 ± 1.21)％,1.36 ± 0.79,0.21 ±0.10,(62.82 ±21.38) ng/L in severe sepsis group; they were (2.86 ±0.88)％,1.25 ±0.56,0.17 ±0.08,(56.38 ± 19.65) ng/L in moderate group; they were (2.61 ± 0.87)％,0.94 ± 0.52,0.15 ± 0.05,(45.43 ± 14.40) ng/L in mild group.The values showed significant statistical difference among the mild,moderate and severe sepsis groups (all P＜0.01).Above values were significandy higher in non-survival group than those in survival group [Treg:(3.46 ±1.53)％ vs.(2.85 ± 1.03)％,t=14.250,P=0.005; miR-155:1.41 ±0.85 vs.1.16 ±0.76,t=11.875,P=0.006;Foxp3 mRNA:0.24 ± 0.11 vs.0.17 ± 0.09,t=8.795,P=0.001 ; IL-10 (ng/L):65.47 ± 23.58 vs.51.70 ± 16.86,t=16.313,P=0.001].The expression of miR-155 was positively correlated with the expression of CD4+CD25+ Treg and Foxp3 mRNA (r1=0.635,P1=0.007; r2=0.671,P2=0.005).Conclusion The result of this study suggest that miR-155 is involved in the cell proliferation regulation of CD4 +CD25 + Treg cells,and play some role in the immunological dissonance in sepsis.